package org.jgroups.util;

import org.jgroups.*;
import org.jgroups.TimeoutException;
import org.jgroups.auth.AuthToken;
import org.jgroups.blocks.Connection;
import org.jgroups.conf.ClassConfigurator;
import org.jgroups.jmx.JmxConfigurator;
import org.jgroups.logging.Log;
import org.jgroups.protocols.*;
import org.jgroups.protocols.pbcast.FLUSH;
import org.jgroups.protocols.pbcast.GMS;
import org.jgroups.protocols.pbcast.NAKACK2;
import org.jgroups.protocols.pbcast.STABLE;
import org.jgroups.protocols.relay.SiteMaster;
import org.jgroups.protocols.relay.SiteUUID;
import org.jgroups.stack.IpAddress;
import org.jgroups.stack.Protocol;
import org.jgroups.stack.ProtocolStack;

import javax.management.MBeanServer;
import javax.management.MBeanServerFactory;

import java.io.*;
import java.lang.annotation.Annotation;
import java.lang.management.ManagementFactory;
import java.lang.management.ThreadInfo;
import java.lang.management.ThreadMXBean;
import java.lang.reflect.Field;
import java.lang.reflect.Method;
import java.lang.reflect.Modifier;
import java.net.*;
import java.nio.ByteBuffer;
import java.nio.channels.WritableByteChannel;
import java.security.MessageDigest;
import java.security.NoSuchAlgorithmException;
import java.text.NumberFormat;
import java.util.*;
import java.util.concurrent.*;
import java.util.regex.Matcher;
import java.util.regex.Pattern;


/**
 * Collection of various utility routines that can not be assigned to other classes.
 * @author Bela Ban
 */
public class Util {

    private static  NumberFormat f;

    private static Map<Class<? extends Object>,Byte> PRIMITIVE_TYPES=new HashMap<Class<? extends Object>,Byte>(15);
    private static final byte TYPE_NULL         =  0;
    private static final byte TYPE_STREAMABLE   =  1;
    private static final byte TYPE_SERIALIZABLE =  2;

    private static final byte TYPE_BOOLEAN      = 10;
    private static final byte TYPE_BYTE         = 11;
    private static final byte TYPE_CHAR         = 12;
    private static final byte TYPE_DOUBLE       = 13;
    private static final byte TYPE_FLOAT        = 14;
    private static final byte TYPE_INT          = 15;
    private static final byte TYPE_LONG         = 16;
    private static final byte TYPE_SHORT        = 17;
    private static final byte TYPE_STRING       = 18;
    private static final byte TYPE_BYTEARRAY    = 19;

    // constants
    public static final int MAX_PORT=65535; // highest port allocatable
    static boolean resolve_dns=false;

    private static short COUNTER=1;

    private static Pattern METHOD_NAME_TO_ATTR_NAME_PATTERN=Pattern.compile("[A-Z]+");
    private static Pattern ATTR_NAME_TO_METHOD_NAME_PATTERN=Pattern.compile("_.");


    protected static int   CCHM_INITIAL_CAPACITY=16;
    protected static float CCHM_LOAD_FACTOR=0.75f;
    protected static int   CCHM_CONCURRENCY_LEVEL=16;

    /** The max size of an address list, e.g. used in View or Digest when toString() is called. Limiting this
     * reduces the amount of log data */
    public static int MAX_LIST_PRINT_SIZE=20;

    public static final Class<?>[] getUnicastProtocols() {
        return new Class<?>[]{UNICAST.class, UNICAST2.class, UNICAST3.class};
    }

    public static enum AddressScope {GLOBAL, SITE_LOCAL, LINK_LOCAL, LOOPBACK, NON_LOOPBACK};

    private static StackType ip_stack_type=_getIpStackType();


    protected static ResourceBundle resource_bundle;


    static {
        resource_bundle=ResourceBundle.getBundle("jg-messages",Locale.getDefault(),Util.class.getClassLoader());

        /* Trying to get value of resolve_dns. PropertyPermission not granted if
        * running in an untrusted environment with JNLP */
        try {
            resolve_dns=Boolean.valueOf(System.getProperty("resolve.dns","false"));
        }
        catch (SecurityException ex){
            resolve_dns=false;
        }
        f=NumberFormat.getNumberInstance();
        f.setGroupingUsed(false);
        // f.setMinimumFractionDigits(2);
        f.setMaximumFractionDigits(2);

        PRIMITIVE_TYPES.put(Boolean.class, TYPE_BOOLEAN);
        PRIMITIVE_TYPES.put(Byte.class, TYPE_BYTE);
        PRIMITIVE_TYPES.put(Character.class, TYPE_CHAR);
        PRIMITIVE_TYPES.put(Double.class, TYPE_DOUBLE);
        PRIMITIVE_TYPES.put(Float.class, TYPE_FLOAT);
        PRIMITIVE_TYPES.put(Integer.class, TYPE_INT);
        PRIMITIVE_TYPES.put(Long.class, TYPE_LONG);
        PRIMITIVE_TYPES.put(Short.class, TYPE_SHORT);
        PRIMITIVE_TYPES.put(String.class, TYPE_STRING);
        PRIMITIVE_TYPES.put(byte[].class, TYPE_BYTEARRAY);

        if(ip_stack_type == StackType.Unknown)
            ip_stack_type=StackType.IPv6;

        try {
            String cchm_initial_capacity=System.getProperty(Global.CCHM_INITIAL_CAPACITY);
            if(cchm_initial_capacity != null)
                CCHM_INITIAL_CAPACITY=Integer.valueOf(cchm_initial_capacity);
        } catch(SecurityException ex) {}

        try {
            String cchm_load_factor=System.getProperty(Global.CCHM_LOAD_FACTOR);
            if(cchm_load_factor != null)
                CCHM_LOAD_FACTOR=Float.valueOf(cchm_load_factor);
        } catch(SecurityException ex) {}

        try {
            String cchm_concurrency_level=System.getProperty(Global.CCHM_CONCURRENCY_LEVEL);
            if(cchm_concurrency_level != null)
                CCHM_CONCURRENCY_LEVEL=Integer.valueOf(cchm_concurrency_level);
        } catch(SecurityException ex) {}

        try {
            String tmp=System.getProperty(Global.MAX_LIST_PRINT_SIZE);
            if(tmp != null)
                MAX_LIST_PRINT_SIZE=Integer.valueOf(tmp);
        } catch(SecurityException ex) {
        }
    }


    public static void assertTrue(boolean condition) {
        assert condition;
    }

    public static void assertTrue(String message, boolean condition) {
        if(message != null)
            assert condition : message;
        else
            assert condition;
    }

    public static void assertFalse(boolean condition) {
        assertFalse(null, condition);
    }

    public static void assertFalse(String message, boolean condition) {
        if(message != null)
            assert !condition : message;
        else
            assert !condition;
    }


    public static void assertEquals(String message, Object val1, Object val2) {
        if(message != null) {
            assert val1.equals(val2) : message;
        }
        else {
            assert val1.equals(val2);
        }
    }

    public static void assertEquals(Object val1, Object val2) {
        assertEquals(null, val1, val2);
    }

    public static void assertNotNull(String message, Object val) {
        if(message != null)
            assert val != null : message;
        else
            assert val != null;
    }


    public static void assertNotNull(Object val) {
        assertNotNull(null, val);
    }


    public static void assertNull(String message, Object val) {
        if(message != null)
            assert val == null : message;
        else
            assert val == null;
    }


    public static int getNextHigherPowerOfTwo(int num) {
       if (num <= 0) return 1;
       int highestBit = Integer.highestOneBit(num);
       return num <= highestBit ? highestBit : highestBit << 1;
    }


    public static String bold(String msg) {
        StringBuilder sb=new StringBuilder("\033[1m");
        sb.append(msg).append("\033[0m");
        return sb.toString();
    }

    public static String getMessage(String key) {
        return key != null? resource_bundle.getString(key) : null;
    }


    /**
     * Returns a default stack for testing with transport = SHARED_LOOPBACK
     * @param additional_protocols Any number of protocols to add to the top of the returned protocol list
     * @return
     */
    public static Protocol[] getTestStack(Protocol ... additional_protocols) {
        Protocol[] protocols={
          new SHARED_LOOPBACK(),
          new PING().timeout(1000),
          new NAKACK2(),
          new UNICAST3(),
          new STABLE(),
          new GMS(),
          new FRAG2().fragSize(8000),
        };

        if(additional_protocols == null)
            return protocols;
        Protocol[] tmp=Arrays.copyOf(protocols, protocols.length + additional_protocols.length);
        System.arraycopy(additional_protocols, 0, tmp, protocols.length, additional_protocols.length);
        return tmp;
    }


    /**
     * Blocks until all channels have the same view
     * @param timeout How long to wait (max in ms)
     * @param interval Check every interval ms
     * @param channels The channels which should form the view. The expected view size is channels.length.
     * Must be non-null
     */
    public static void waitUntilAllChannelsHaveSameSize(long timeout, long interval, Channel... channels) throws TimeoutException {
        int size=channels.length;

        if(interval >= timeout || timeout <= 0)
            throw new IllegalArgumentException("interval needs to be smaller than timeout or timeout needs to be > 0");
        long target_time=System.currentTimeMillis() + timeout;
        while(System.currentTimeMillis() <= target_time) {
            boolean all_channels_have_correct_size=true;
            for(Channel ch: channels) {
                View view=ch.getView();
                if(view == null || view.size() != size) {
                    all_channels_have_correct_size=false;
                    break;
                }
            }
            if(all_channels_have_correct_size)
                return;
            Util.sleep(interval);
        }
        View[] views=new View[channels.length];
        StringBuilder sb=new StringBuilder();
        for(int i=0; i < channels.length; i++) {
            views[i]=channels[i].getView();
            sb.append(channels[i].getName()).append(": ").append(views[i]).append("\n");
        }
        for(View view: views)
            if(view == null || view.size() != size)
                throw new TimeoutException("Timeout " + timeout + " kicked in, views are:\n" + sb);
    }


    /**
     * Waits until a list has the expected number of elements. Throws an exception if not met
     * @param list The list
     * @param expected_size The expected size
     * @param timeout The time to wait (in ms)
     * @param interval The interval at which to get the size of the list (in ms)
     * @param <T> The type of the list
     */
    public static <T> void waitUntilListHasSize(List<T> list, int expected_size, long timeout, long interval) {
        if(list == null)
            throw new IllegalStateException("list is null");
        long target_time=System.currentTimeMillis() + timeout;
        while(System.currentTimeMillis() < target_time) {
            if(list.size() == expected_size)
                break;
            Util.sleep(interval);
        }
        assert list.size() == expected_size : "list doesn't have the expected (" + expected_size + ") elements: " + list;
    }


    public static void addFlush(Channel ch, FLUSH flush) {
        if(ch == null || flush == null)
            throw new IllegalArgumentException("ch and flush have to be non-null");
        ProtocolStack stack=ch.getProtocolStack();
        stack.insertProtocolAtTop(flush);
    }


    public static void setScope(Message msg, short scope) {
        SCOPE.ScopeHeader hdr=SCOPE.ScopeHeader.createMessageHeader(scope);
        msg.putHeader(Global.SCOPE_ID, hdr);
        msg.setFlag(Message.Flag.SCOPED);
    }

    public static short getScope(Message msg) {
        SCOPE.ScopeHeader hdr=(SCOPE.ScopeHeader)msg.getHeader(Global.SCOPE_ID);
        return hdr != null? hdr.getScope() : 0;
    }

   public static byte[] createAuthenticationDigest(String passcode, long t1, double q1) throws IOException,
            NoSuchAlgorithmException {
      ByteArrayOutputStream baos = new ByteArrayOutputStream(128);
      DataOutputStream out = new DataOutputStream(baos);
      byte[] digest = createDigest(passcode, t1, q1);
      out.writeLong(t1);
      out.writeDouble(q1);
      out.writeInt(digest.length);
      out.write(digest);
      out.flush();
      return baos.toByteArray();
   }

    public static byte[] createDigest(String passcode, long t1, double q1)
      throws IOException, NoSuchAlgorithmException {
        MessageDigest md = MessageDigest.getInstance("SHA");
        md.update(passcode.getBytes());
        ByteBuffer bb = ByteBuffer.allocate(16); //8 bytes for long and double each
        bb.putLong(t1);
        bb.putDouble(q1);
        md.update(bb);
        return md.digest();
    }

    /**
     * Utility method. If the dest address is IPv6, convert scoped link-local addrs into unscoped ones
     * @param sock
     * @param dest
     * @param sock_conn_timeout
     * @throws IOException
     */
    public static void connect(Socket sock, SocketAddress dest, int sock_conn_timeout) throws IOException {
        if(dest instanceof InetSocketAddress) {
            InetAddress addr=((InetSocketAddress)dest).getAddress();
            if(addr instanceof Inet6Address) {
                Inet6Address tmp=(Inet6Address)addr;
                if(tmp.getScopeId() != 0) {
                    dest=new InetSocketAddress(InetAddress.getByAddress(tmp.getAddress()), ((InetSocketAddress)dest).getPort());
                }
            }
        }
        sock.connect(dest, sock_conn_timeout);
    }

    public static void close(InputStream inp) {
        if(inp != null)
            try {inp.close();} catch(IOException e) {}
    }

    public static void close(OutputStream out) {
        if(out != null) {
            try {out.close();} catch(IOException e) {}
        }
    }

    public static void close(Socket s) {
        if(s != null) {
            try {s.close();} catch(Exception ex) {}
        }
    }

    public static void close(ServerSocket s) {
        if(s != null) {
            try {s.close();} catch(Exception ex) {}
        }
    }

    public static void close(DatagramSocket my_sock) {
        if(my_sock != null) {
            try {my_sock.close();} catch(Throwable t) {}
        }
    }

    public static void close(Channel ch) {
        if(ch != null) {
            try {ch.close();} catch(Throwable t) {}
        }
    }

    public static void close(Channel ... channels) {
        if(channels != null) {
            for(Channel ch: channels)
                Util.close(ch);
        }
    }

    public static void close(Connection conn) {
        if(conn != null) {
            try {conn.close();} catch(Throwable t) {}
        }
    }

    public static void close(Connection ... conns) {
        for(Connection conn: conns)
            close(conn);
    }

    /** Drops messages to/from other members and then closes the channel. Note that this member won't get excluded from
     * the view until failure detection has kicked in and the new coord installed the new view */
    public static void shutdown(Channel ch) throws Exception {
        DISCARD discard=new DISCARD();
        discard.setLocalAddress(ch.getAddress());
        discard.setDiscardAll(true);
        ProtocolStack stack=ch.getProtocolStack();
        TP transport=stack.getTransport();
        stack.insertProtocol(discard,  ProtocolStack.ABOVE, transport.getClass());

        //abruptly shutdown FD_SOCK just as in real life when member gets killed non gracefully
        FD_SOCK fd = (FD_SOCK) ch.getProtocolStack().findProtocol(FD_SOCK.class);
        if(fd != null)
            fd.stopServerSocket(false);

        View view=ch.getView();
        if (view != null) {
            ViewId vid = view.getViewId();
            List<Address> members = Arrays.asList(ch.getAddress());

            ViewId new_vid = new ViewId(ch.getAddress(), vid.getId() + 1);
            View new_view = new View(new_vid, members);

            // inject view in which the shut down member is the only element
            GMS gms = (GMS) stack.findProtocol(GMS.class);
            gms.installView(new_view);
        }
        Util.close(ch);
    }


    public static byte setFlag(byte bits, byte flag) {
        return bits |= flag;
    }


    public static boolean isFlagSet(byte bits, byte flag) {
        return (bits & flag) == flag;
    }


    public static byte clearFlags(byte bits, byte flag) {
        return bits &= ~flag;
    }



    /**
     * Creates an object from a byte buffer
     */
    public static Object objectFromByteBuffer(byte[] buffer) throws Exception {
        if(buffer == null) return null;
        return objectFromByteBuffer(buffer, 0, buffer.length);
    }

    public static Object objectFromByteBuffer(byte[] buffer,int offset,int length) throws Exception {
        return objectFromByteBuffer(buffer, offset, length, null);
    }


    public static Object objectFromByteBuffer(byte[] buffer,int offset,int length, ClassLoader loader) throws Exception {
        if(buffer == null) return null;
        Object retval=null;
        byte type=buffer[offset];


        switch(type) {
            case TYPE_NULL:
                return null;
            case TYPE_STREAMABLE:
                ByteArrayInputStream in_stream=new ExposedByteArrayInputStream(buffer, offset+1, length-1);
                InputStream in=new DataInputStream(in_stream);
                retval=readGenericStreamable((DataInputStream)in, loader);
                break;
            case TYPE_SERIALIZABLE: // the object is Externalizable or Serializable
                in_stream=new ExposedByteArrayInputStream(buffer, offset+1, length-1);
                in=new ObjectInputStreamWithClassloader(in_stream, loader); // changed Nov 29 2004 (bela)
                try {
                    retval=((ObjectInputStream)in).readObject();
                }
                finally {
                    Util.close(in);
                }
                break;
            case TYPE_BOOLEAN:
                return ByteBuffer.wrap(buffer, offset + 1, length - 1).get() == 1;
            case TYPE_BYTE:
                return ByteBuffer.wrap(buffer, offset + 1, length - 1).get();
            case TYPE_CHAR:
                return ByteBuffer.wrap(buffer, offset + 1, length - 1).getChar();
            case TYPE_DOUBLE:
                return ByteBuffer.wrap(buffer, offset + 1, length - 1).getDouble();
            case TYPE_FLOAT:
                return ByteBuffer.wrap(buffer, offset + 1, length - 1).getFloat();
            case TYPE_INT:
                return ByteBuffer.wrap(buffer, offset + 1, length - 1).getInt();
            case TYPE_LONG:
                return ByteBuffer.wrap(buffer, offset + 1, length - 1).getLong();
            case TYPE_SHORT:
                return ByteBuffer.wrap(buffer, offset + 1, length - 1).getShort();
            case TYPE_STRING:
                byte[] tmp=new byte[length -1];
                System.arraycopy(buffer, offset +1, tmp, 0, length -1);
                return new String(tmp);
            case TYPE_BYTEARRAY:
                tmp=new byte[length -1];
                System.arraycopy(buffer, offset +1, tmp, 0, length -1);
                return tmp;
            default:
                throw new IllegalArgumentException("type " + type + " is invalid");
        }
        return retval;
    }




    /**
     * Serializes/Streams an object into a byte buffer.
     * The object has to implement interface Serializable or Externalizable or Streamable.
     */
    public static byte[] objectToByteBuffer(Object obj) throws Exception {
        if(obj == null)
            return ByteBuffer.allocate(Global.BYTE_SIZE).put(TYPE_NULL).array();

        if(obj instanceof Streamable) {
            final ExposedByteArrayOutputStream out_stream=new ExposedByteArrayOutputStream(128);
            final ExposedDataOutputStream out=new ExposedDataOutputStream(out_stream);
            out_stream.write(TYPE_STREAMABLE);
            writeGenericStreamable((Streamable)obj, out);
            return out_stream.toByteArray();
        }

        Byte type=PRIMITIVE_TYPES.get(obj.getClass());
        if(type == null) { // will throw an exception if object is not serializable
            final ExposedByteArrayOutputStream out_stream=new ExposedByteArrayOutputStream(128);
            out_stream.write(TYPE_SERIALIZABLE);
            ObjectOutputStream out=new ObjectOutputStream(out_stream);
            out.writeObject(obj);
            out.close();
            return out_stream.toByteArray();
        }

        switch(type) {
            case TYPE_BOOLEAN:
                return ByteBuffer.allocate(Global.BYTE_SIZE * 2).put(TYPE_BOOLEAN)
                  .put((Boolean)obj? (byte)1 : (byte)0).array();
            case TYPE_BYTE:
                return ByteBuffer.allocate(Global.BYTE_SIZE *2).put(TYPE_BYTE).put((Byte)obj).array();
            case TYPE_CHAR:
                return ByteBuffer.allocate(Global.BYTE_SIZE *3).put(TYPE_CHAR).putChar((Character)obj).array();
            case TYPE_DOUBLE:
                return ByteBuffer.allocate(Global.BYTE_SIZE + Global.DOUBLE_SIZE).put(TYPE_DOUBLE)
                        .putDouble((Double)obj).array();
            case TYPE_FLOAT:
                return ByteBuffer.allocate(Global.BYTE_SIZE + Global.FLOAT_SIZE).put(TYPE_FLOAT)
                        .putFloat((Float)obj).array();
            case TYPE_INT:
                return ByteBuffer.allocate(Global.BYTE_SIZE + Global.INT_SIZE).put(TYPE_INT)
                        .putInt((Integer)obj).array();
            case TYPE_LONG:
                return ByteBuffer.allocate(Global.BYTE_SIZE + Global.LONG_SIZE).put(TYPE_LONG)
                        .putLong((Long)obj).array();
            case TYPE_SHORT:
                return ByteBuffer.allocate(Global.BYTE_SIZE + Global.SHORT_SIZE).put(TYPE_SHORT)
                        .putShort((Short)obj).array();
            case TYPE_STRING:
                String str=(String)obj;
                byte[] buf=new byte[str.length()];
                for(int i=0; i < buf.length; i++)
                    buf[i]=(byte)str.charAt(i);
                return ByteBuffer.allocate(Global.BYTE_SIZE + buf.length).put(TYPE_STRING).put(buf, 0, buf.length).array();
            case TYPE_BYTEARRAY:
                buf=(byte[])obj;
                return ByteBuffer.allocate(Global.BYTE_SIZE + buf.length).put(TYPE_BYTEARRAY)
                        .put(buf, 0, buf.length).array();
            default:
                throw new IllegalArgumentException("type " + type + " is invalid");
        }

    }



    public static void objectToStream(Object obj, DataOutput out) throws Exception {
        if(obj == null) {
            out.write(TYPE_NULL);
            return;
        }

        Byte type;
        if(obj instanceof Streamable) {  // use Streamable if we can
            out.write(TYPE_STREAMABLE);
            writeGenericStreamable((Streamable)obj, out);
        }
        else if((type=PRIMITIVE_TYPES.get(obj.getClass())) != null) {
            out.write(type.byteValue());
            switch(type.byteValue()) {
                case TYPE_BOOLEAN:
                    out.writeBoolean(((Boolean)obj).booleanValue());
                    break;
                case TYPE_BYTE:
                    out.writeByte(((Byte)obj).byteValue());
                    break;
                case TYPE_CHAR:
                    out.writeChar(((Character)obj).charValue());
                    break;
                case TYPE_DOUBLE:
                    out.writeDouble(((Double)obj).doubleValue());
                    break;
                case TYPE_FLOAT:
                    out.writeFloat(((Float)obj).floatValue());
                    break;
                case TYPE_INT:
                    out.writeInt(((Integer)obj).intValue());
                    break;
                case TYPE_LONG:
                    out.writeLong(((Long)obj).longValue());
                    break;
                case TYPE_SHORT:
                    out.writeShort(((Short)obj).shortValue());
                    break;
                case TYPE_STRING:
                    String str=(String)obj;
                    if(str.length() > Short.MAX_VALUE) {
                        out.writeBoolean(true);
                        ObjectOutputStream oos=new ObjectOutputStream((OutputStream)out);
                        try {
                            oos.writeObject(str);
                        }
                        finally {
                            oos.close();
                        }
                    }
                    else {
                        out.writeBoolean(false);
                        out.writeUTF(str);
                    }
                    break;
                case TYPE_BYTEARRAY:
                    byte[] buf=(byte[])obj;
                    out.writeInt(buf.length);
                    out.write(buf, 0, buf.length);
                    break;
                default:
                    throw new IllegalArgumentException("type " + type + " is invalid");
            }
        }
        else { // will throw an exception if object is not serializable
            out.write(TYPE_SERIALIZABLE);
            ObjectOutputStream tmp=new ObjectOutputStream((OutputStream)out);
            tmp.writeObject(obj);
        }
    }

    public static Object objectFromStream(DataInput in) throws Exception {
        return objectFromStream(in, null);
    }

    public static Object objectFromStream(DataInput in, ClassLoader loader) throws Exception {
        if(in == null) return null;
        Object retval=null;
        byte b=in.readByte();

        switch(b) {
            case TYPE_NULL:
                return null;
            case TYPE_STREAMABLE:
                retval=readGenericStreamable(in, loader);
                break;
            case TYPE_SERIALIZABLE: // the object is Externalizable or Serializable
                ObjectInputStream tmp=new ObjectInputStreamWithClassloader((InputStream)in, loader);
                retval=tmp.readObject();
                break;
            case TYPE_BOOLEAN:
                retval=Boolean.valueOf(in.readBoolean());
                break;
            case TYPE_BYTE:
                retval=Byte.valueOf(in.readByte());
                break;
            case TYPE_CHAR:
                retval=Character.valueOf(in.readChar());
                break;
            case TYPE_DOUBLE:
                retval=Double.valueOf(in.readDouble());
                break;
            case TYPE_FLOAT:
                retval=Float.valueOf(in.readFloat());
                break;
            case TYPE_INT:
                retval=Integer.valueOf(in.readInt());
                break;
            case TYPE_LONG:
                retval=Long.valueOf(in.readLong());
                break;
            case TYPE_SHORT:
                retval=Short.valueOf(in.readShort());
                break;
            case TYPE_STRING:
                if(in.readBoolean()) { // large string
                    ObjectInputStream ois=new ObjectInputStream((InputStream)in);
                    try {
                        retval=ois.readObject();
                    }
                    finally {
                        ois.close();
                    }
                }
                else {
                    retval=in.readUTF();
                }
                break;
            case TYPE_BYTEARRAY:
                int len=in.readInt();
                byte[] tmpbuf=new byte[len];
                in.readFully(tmpbuf, 0, tmpbuf.length);
                retval=tmpbuf;
                break;
            default:
                throw new IllegalArgumentException("type " + b + " is invalid");
        }
        return retval;
    }


    public static Streamable streamableFromByteBuffer(Class<? extends Streamable> cl, byte[] buffer) throws Exception {
        if(buffer == null) return null;
        Streamable retval=null;
        ByteArrayInputStream in_stream=new ExposedByteArrayInputStream(buffer);
        DataInputStream in=new DataInputStream(in_stream); // changed Nov 29 2004 (bela)
        retval=cl.newInstance();
        retval.readFrom(in);
        in.close();
        return retval;
    }


    public static <T extends Streamable> Streamable streamableFromByteBuffer(Class<T> cl, byte[] buffer, int offset, int length) throws Exception {
        if(buffer == null) return null;
        ByteArrayInputStream in_stream=new ExposedByteArrayInputStream(buffer, offset, length);
        DataInputStream in=new DataInputStream(in_stream); // changed Nov 29 2004 (bela)
        T retval=cl.newInstance();
        retval.readFrom(in);
        in.close();
        return retval;
    }


    public static <T extends Streamable> T streamableFromBuffer(Class<T> clazz, byte[] buffer, int offset, int length) throws Exception {
        ByteArrayInputStream in_stream=new ExposedByteArrayInputStream(buffer, offset, length);
        DataInputStream in=new DataInputStream(in_stream); // changed Nov 29 2004 (bela)
        return (T)Util.readStreamable(clazz,in);
    }

    public static <T extends Streamable> T streamableFromBuffer(Class<T> clazz, byte[] buffer) throws Exception {
        return streamableFromBuffer(clazz,buffer,0,buffer.length);
    }


    public static byte[] streamableToByteBuffer(Streamable obj) throws Exception {
        byte[] result=null;
        final ByteArrayOutputStream out_stream=new ExposedByteArrayOutputStream(512);
        DataOutputStream out=new ExposedDataOutputStream(out_stream);
        obj.writeTo(out);
        result=out_stream.toByteArray();
        out.close();
        return result;
    }

    public static Buffer streamableToBuffer(Streamable obj) {
        final ExposedByteArrayOutputStream out_stream=new ExposedByteArrayOutputStream(512);
        DataOutputStream out=new ExposedDataOutputStream(out_stream);
        try {
            Util.writeStreamable(obj,out);
            return out_stream.getBuffer();
        }
        catch(Exception ex) {
            return null;
        }
    }


    public static byte[] collectionToByteBuffer(Collection<Address> c) throws Exception {
        byte[] result=null;
        final ByteArrayOutputStream out_stream=new ExposedByteArrayOutputStream(512);
        DataOutputStream out=new ExposedDataOutputStream(out_stream);
        Util.writeAddresses(c, out);
        result=out_stream.toByteArray();
        out.close();
        return result;
    }



    public static void writeAuthToken(AuthToken token, DataOutput out) throws Exception{
        Util.writeString(token.getName(), out);
        token.writeTo(out);
    }

    public static AuthToken readAuthToken(DataInput in) throws Exception {
        try{
            String type = Util.readString(in);
            Object obj = Class.forName(type).newInstance();
            AuthToken token = (AuthToken) obj;
            token.readFrom(in);
            return token;
        }
        catch(ClassNotFoundException cnfe) {
            return null;
        }
    }


    public static void writeView(View view, DataOutput out) throws Exception {
        if(view == null) {
            out.writeBoolean(false);
            return;
        }
        out.writeBoolean(true);
        out.writeBoolean(view instanceof MergeView);
        view.writeTo(out);
    }


    public static View readView(DataInput in) throws Exception {
        if(in.readBoolean() == false)
            return null;
        boolean isMergeView=in.readBoolean();
        View view;
        if(isMergeView)
            view=new MergeView();
        else
            view=new View();
        view.readFrom(in);
        return view;
    }

    public static void writeViewId(ViewId vid, DataOutput out) throws Exception {
        if(vid == null) {
            out.writeBoolean(false);
            return;
        }
        out.writeBoolean(true);
        vid.writeTo(out);
    }

    public static ViewId readViewId(DataInput in) throws Exception {
        if(in.readBoolean() == false)
            return null;
        ViewId retval=new ViewId();
        retval.readFrom(in);
        return retval;
    }


    public static void writeAddress(Address addr, DataOutput out) throws Exception {
        byte flags=0;
        boolean streamable_addr=true;

        if(addr == null) {
            flags=Util.setFlag(flags, Address.NULL);
            out.writeByte(flags);
            return;
        }

        if(addr instanceof UUID) {
            Class<? extends Address> clazz=addr.getClass();
            if(clazz.equals(UUID.class))
                flags=Util.setFlag(flags, Address.UUID_ADDR);
            else if(clazz.equals(SiteUUID.class))
                flags=Util.setFlag(flags, Address.SITE_UUID);
            else if(clazz.equals(SiteMaster.class))
                flags=Util.setFlag(flags,Address.SITE_MASTER);
            else
                streamable_addr=false;
        }
        else if(addr instanceof IpAddress)
            flags=Util.setFlag(flags, Address.IP_ADDR);
        else
            streamable_addr=false;
        out.writeByte(flags);
        if(streamable_addr)
            addr.writeTo(out);
        else
            writeOtherAddress(addr, out);
    }

    public static Address readAddress(DataInput in) throws Exception {
        byte flags=in.readByte();
        if(Util.isFlagSet(flags, Address.NULL))
            return null;

        Address addr;
        if(Util.isFlagSet(flags, Address.UUID_ADDR)) {
            addr=new UUID();
            addr.readFrom(in);
        }
        else if(Util.isFlagSet(flags, Address.SITE_UUID)) {
            addr=new SiteUUID();
            addr.readFrom(in);
        }
        else if(Util.isFlagSet(flags, Address.SITE_MASTER)) {
            addr=new SiteMaster();
            addr.readFrom(in);
        }
        else if(Util.isFlagSet(flags, Address.IP_ADDR)) {
            addr=new IpAddress();
            addr.readFrom(in);
        }
        else {
            addr=readOtherAddress(in);
        }
        return addr;
    }

    public static int size(Address addr) {
        int retval=Global.BYTE_SIZE; // flags
        if(addr == null)
            return retval;

        if(addr instanceof UUID) {
            Class<? extends Address> clazz=addr.getClass();
            if(clazz.equals(UUID.class) || clazz.equals(SiteUUID.class) || clazz.equals(SiteMaster.class))
                return retval+addr.size();
        }
        if(addr instanceof IpAddress)
            return retval+addr.size();

        retval+=Global.SHORT_SIZE; // magic number
        retval+=addr.size();
        return retval;
    }


    public static int size(View view) {
        int retval=Global.BYTE_SIZE; // presence
        if(view != null)
            retval+=view.serializedSize() + Global.BYTE_SIZE; // merge view or regular view
        return retval;
    }

    public static int size(ViewId vid) {
        int retval=Global.BYTE_SIZE; // presence
        if(vid != null)
            retval+=vid.serializedSize();
        return retval;
    }

    public static int size(String s) {
        int retval=Global.BYTE_SIZE;
        if(s != null)
            retval+=s.length() +2;
        return retval;
    }

    public static int size(byte[] buf) {
        int retval=Global.BYTE_SIZE + Global.INT_SIZE;
        if(buf != null)
            retval+=buf.length;
        return retval;
    }

    private static Address readOtherAddress(DataInput in) throws Exception {
        short magic_number=in.readShort();
        Class<?> cl=ClassConfigurator.get(magic_number);
        if(cl == null)
            throw new RuntimeException("class for magic number " + magic_number + " not found");
        Address addr=(Address)cl.newInstance();
        addr.readFrom(in);
        return addr;
    }

    private static void writeOtherAddress(Address addr, DataOutput out) throws Exception {
        short magic_number=ClassConfigurator.getMagicNumber(addr.getClass());

        // write the class info
        if(magic_number == -1)
            throw new RuntimeException("magic number " + magic_number + " not found");

        out.writeShort(magic_number);
        addr.writeTo(out);
    }

    /**
     * Writes a list of Addresses. Can contain 65K addresses at most
     *
     * @param v A Collection<Address>
     * @param out
     * @throws Exception
     */
    public static void writeAddresses(Collection<? extends Address> v, DataOutput out) throws Exception {
        if(v == null) {
            out.writeShort(-1);
            return;
        }
        out.writeShort(v.size());
        for(Address addr: v) {
            Util.writeAddress(addr, out);
        }
    }

    public static void writeAddresses(final Address[] addrs, DataOutput out) throws Exception {
        if(addrs == null) {
            out.writeShort(-1);
            return;
        }
        out.writeShort(addrs.length);
        for(Address addr: addrs)
            Util.writeAddress(addr, out);
    }

    /**
     *
     *
     * @param in
     * @param cl The type of Collection, e.g. ArrayList.class
     * @return Collection of Address objects
     * @throws Exception
     */
    public static Collection<? extends Address> readAddresses(DataInput in, Class cl) throws Exception {
        short length=in.readShort();
        if(length < 0) return null;
        Collection<Address> retval=(Collection<Address>)cl.newInstance();
        Address addr;
        for(int i=0; i < length; i++) {
            addr=Util.readAddress(in);
            retval.add(addr);
        }
        return retval;
    }


    public static Address[] readAddresses(DataInput in) throws Exception {
        short length=in.readShort();
        if(length < 0) return null;
        Address[] retval=new Address[length];
        for(int i=0; i < length; i++) {
            Address addr=Util.readAddress(in);
            retval[i]=addr;
        }
        return retval;
    }


    /**
     * Returns the marshalled size of a Collection of Addresses.
     * <em>Assumes elements are of the same type !</em>
     * @param addrs Collection<Address>
     * @return long size
     */
    public static long size(Collection<? extends Address> addrs) {
        int retval=Global.SHORT_SIZE; // number of elements
        if(addrs != null && !addrs.isEmpty()) {
            Address addr=addrs.iterator().next();
            retval+=size(addr) * addrs.size();
        }
        return retval;
    }

    public static long size(Address[] addrs) {
        int retval=Global.SHORT_SIZE; // number of elements
        if(addrs != null)
            for(Address addr: addrs)
                retval+=Util.size(addr);
        return retval;
    }


    public static void writeStreamable(Streamable obj, DataOutput out) throws Exception {
        if(obj == null) {
            out.writeBoolean(false);
            return;
        }
        out.writeBoolean(true);
        obj.writeTo(out);
    }


    public static Streamable readStreamable(Class clazz, DataInput in) throws Exception {
        Streamable retval=null;
        if(in.readBoolean() == false)
            return null;
        retval=(Streamable)clazz.newInstance();
        retval.readFrom(in);
        return retval;
    }


    public static void writeGenericStreamable(Streamable obj, DataOutput out) throws Exception {
        short magic_number;
        String classname;

        if(obj == null) {
            out.write(0);
            return;
        }

        out.write(1);
        magic_number=ClassConfigurator.getMagicNumber(obj.getClass());
        // write the magic number or the class name
        if(magic_number == -1) {
            out.writeBoolean(false);
            classname=obj.getClass().getName();
            out.writeUTF(classname);
        }
        else {
            out.writeBoolean(true);
            out.writeShort(magic_number);
        }

        // write the contents
        obj.writeTo(out);
    }

    public static Streamable readGenericStreamable(DataInput in) throws Exception {
        return readGenericStreamable(in, null);
    }

    public static Streamable readGenericStreamable(DataInput in, ClassLoader loader) throws Exception {
        Streamable retval=null;
        int b=in.readByte();
        if(b == 0)
            return null;

        boolean use_magic_number=in.readBoolean();
        String classname;
        Class clazz;

        if(use_magic_number) {
            short magic_number=in.readShort();
            clazz=ClassConfigurator.get(magic_number);
            if (clazz==null)
                throw new ClassNotFoundException("Class for magic number "+magic_number+" cannot be found.");
        }
        else {
            classname=in.readUTF();
            clazz=ClassConfigurator.get(classname, loader);
        }

        retval=(Streamable)clazz.newInstance();
        retval.readFrom(in);
        return retval;
    }

    public static void writeClass(Class<?> classObject, DataOutput out) throws Exception {
        short magic_number=ClassConfigurator.getMagicNumber(classObject);
        // write the magic number or the class name
        if(magic_number == -1) {
            out.writeBoolean(false);
            out.writeUTF(classObject.getName());
        }
        else {
            out.writeBoolean(true);
            out.writeShort(magic_number);
        }
    }

    public static Class<?> readClass(DataInput in) throws Exception {
        Class<?> clazz;
        boolean use_magic_number = in.readBoolean();
        if(use_magic_number) {
            short magic_number=in.readShort();
            clazz=ClassConfigurator.get(magic_number);
            if(clazz == null)
                throw new ClassNotFoundException("Class for magic number "+magic_number+" cannot be found.");
        }
        else {
            String classname=in.readUTF();
            clazz=ClassConfigurator.get(classname);
        }

        return clazz;
    }

    public static void writeObject(Object obj, DataOutput out) throws Exception {
        if(obj instanceof Streamable) {
            out.writeInt(-1);
            writeGenericStreamable((Streamable)obj, out);
        }
        else {
            byte[] buf=objectToByteBuffer(obj);
            out.writeInt(buf.length);
            out.write(buf, 0, buf.length);
        }
    }

    public static Object readObject(DataInput in) throws Exception {
        int len=in.readInt();
        if(len == -1)
            return readGenericStreamable(in);

        byte[] buf=new byte[len];
        in.readFully(buf, 0, len);
        return objectFromByteBuffer(buf);
    }



    public static void writeString(String s, DataOutput out) throws Exception {
        if(s != null) {
            out.write(1);
            out.writeUTF(s);
        }
        else {
            out.write(0);
        }
    }


    public static String readString(DataInput in) throws Exception {
        int b=in.readByte();
        if(b == 1)
            return in.readUTF();
        return null;
    }


    public static String readFile(String filename) throws FileNotFoundException {
        FileInputStream in=new FileInputStream(filename);
        return readContents(in);
    }


    public static String readContents(InputStream input) {
        StringBuilder sb=new StringBuilder();
        int ch;
        while(true) {
            try {
                ch=input.read();
                if(ch != -1)
                    sb.append((char)ch);
                else
                    break;
            }
            catch(IOException e) {
                break;
            }
        }
        return sb.toString();
    }

    public static byte[] readFileContents(String filename) throws IOException {
        File file=new File(filename);
        if(!file.exists())
            throw new FileNotFoundException(filename);
        long length=file.length();
        byte contents[]=new byte[(int)length];
        InputStream in=new BufferedInputStream(new FileInputStream(filename));
        int bytes_read=0;

        for(;;) {
            int tmp=in.read(contents, bytes_read, (int)(length - bytes_read));
            if(tmp == -1)
                break;
            bytes_read+=tmp;
            if(bytes_read == length)
                break;
        }
        return contents;
    }

    public static byte[] readFileContents(InputStream input) throws IOException {
        byte contents[]=new byte[10000], buf[]=new byte[1024];
        InputStream in=new BufferedInputStream(input);
        int bytes_read=0;

        for(;;) {
            int tmp=in.read(buf, 0, buf.length);
            if(tmp == -1)
                break;
            System.arraycopy(buf, 0, contents, bytes_read, tmp);
            bytes_read+=tmp;
        }

        byte[] retval=new byte[bytes_read];
        System.arraycopy(contents, 0, retval, 0, bytes_read);
        return retval;
    }


    public static String parseString(DataInput in) {
        StringBuilder sb=new StringBuilder();
        int ch;

        // read white space
        while(true) {
            try {
                ch=in.readByte();
                if(ch == -1) {
                    return null; // eof
                }
                if(Character.isWhitespace(ch)) {
                    if(ch == '\n')
                        return null;
                }
                else {
                    sb.append((char)ch);
                    break;
                }
            }
            catch(EOFException eof) {
                return null;
            }
            catch(IOException e) {
                break;
            }
        }

        while(true) {
            try {
                ch=in.readByte();
                if(ch == -1)
                    break;
                if(Character.isWhitespace(ch))
                    break;
                else {
                    sb.append((char)ch);
                }
            }
            catch(IOException e) {
                break;
            }
        }

        return sb.toString();
    }

    public static String readStringFromStdin(String message) throws Exception {
        System.out.print(message);
        System.out.flush();
        System.in.skip(System.in.available());
        BufferedReader reader=new BufferedReader(new InputStreamReader(System.in));
        return reader.readLine().trim();
    }

    public static long readLongFromStdin(String message) throws Exception {
        String tmp=readStringFromStdin(message);
        return Long.parseLong(tmp);
    }

    public static double readDoubleFromStdin(String message) throws Exception {
        String tmp=readStringFromStdin(message);
        return Double.parseDouble(tmp);
    }

    public static int readIntFromStdin(String message) throws Exception {
        String tmp=readStringFromStdin(message);
        return Integer.parseInt(tmp);
    }


    public static void writeByteBuffer(byte[] buf, DataOutput out) throws Exception {
        writeByteBuffer(buf, 0, buf.length, out);
    }

     public static void writeByteBuffer(byte[] buf, int offset, int length, DataOutput out) throws Exception {
        if(buf != null) {
            out.write(1);
            out.writeInt(length);
            out.write(buf, offset, length);
        }
        else {
            out.write(0);
        }
    }

    public static byte[] readByteBuffer(DataInput in) throws Exception {
        int b=in.readByte();
        if(b == 1) {
            b=in.readInt();
            byte[] buf=new byte[b];
            in.readFully(buf, 0, buf.length);
            return buf;
        }
        return null;
    }


    public static Buffer messageToByteBuffer(Message msg) throws Exception {
        ExposedByteArrayOutputStream output=new ExposedByteArrayOutputStream(512);
        DataOutputStream out=new ExposedDataOutputStream(output);

        out.writeBoolean(msg != null);
        if(msg != null)
            msg.writeTo(out);
        out.flush();
        Buffer retval=new Buffer(output.getRawBuffer(), 0, output.size());
        out.close();
        output.close();
        return retval;
    }

    public static Message byteBufferToMessage(byte[] buffer, int offset, int length) throws Exception {
        ByteArrayInputStream input=new ExposedByteArrayInputStream(buffer, offset, length);
        DataInputStream in=new DataInputStream(input);

        if(!in.readBoolean())
            return null;

        Message msg=new Message(false); // don't create headers, readFrom() will do this
        msg.readFrom(in);
        return msg;
    }



    /**
       * Marshalls a list of messages.
       * @param xmit_list LinkedList<Message>
       * @return Buffer
       * @throws Exception
       */
    public static Buffer msgListToByteBuffer(List<Message> xmit_list) throws Exception {
        ExposedByteArrayOutputStream output=new ExposedByteArrayOutputStream(512);
        DataOutputStream out=new ExposedDataOutputStream(output);
        Buffer retval=null;

        out.writeInt(xmit_list.size());
        for(Message msg: xmit_list) {
            msg.writeTo(out);
        }
        out.flush();
        retval=new Buffer(output.getRawBuffer(), 0, output.size());
        out.close();
        output.close();
        return retval;
    }




    public static <T> boolean match(T obj1, T obj2) {
        if(obj1 == null && obj2 == null)
            return true;
        if(obj1 != null)
            return obj1.equals(obj2);
        else
            return obj2.equals(obj1);
    }



    public static boolean match(long[] a1, long[] a2) {
        if(a1 == null && a2 == null)
            return true;
        if(a1 == null || a2 == null)
            return false;

        if(a1.hashCode() == a2.hashCode()) // identity
            return true;

        // at this point, a1 != null and a2 != null
        if(a1.length != a2.length)
            return false;

        for(int i=0; i < a1.length; i++) {
            if(a1[i] != a2[i])
                return false;
        }
        return true;
    }


    public static boolean patternMatch(String pattern, String str) {
        Pattern pat=Pattern.compile(pattern);
        Matcher matcher=pat.matcher(str);
        return matcher.matches();
    }

    public static void main(String[] args) {
        boolean result=patternMatch(args[0],args[1]);
        System.out.println(args[1] + " matches " + args[0] + ": " + result);
    }


    public static <T> boolean different(T one, T two) {
        return !match(one, two);
    }


    /** Sleep for timeout msecs. Returns when timeout has elapsed or thread was interrupted */
    public static void sleep(long timeout) {
        try {
            Thread.sleep(timeout);
        }
        catch(InterruptedException e) {
            Thread.currentThread().interrupt();
        }
    }


    public static void sleep(long timeout, int nanos) {
        try {
            Thread.sleep(timeout,nanos);
        }
        catch(InterruptedException e) {
            Thread.currentThread().interrupt();
        }
    }


    /**
     * On most UNIX systems, the minimum sleep time is 10-20ms. Even if we specify sleep(1), the thread will
     * sleep for at least 10-20ms. On Windows, sleep() seems to be implemented as a busy sleep, that is the
     * thread never relinquishes control and therefore the sleep(x) is exactly x ms long.
     */
    public static void sleep(long msecs, boolean busy_sleep) {
        if(!busy_sleep) {
            sleep(msecs);
            return;
        }

        long start=System.currentTimeMillis();
        long stop=start + msecs;

        while(stop > start) {
            start=System.currentTimeMillis();
        }
    }


    public static int keyPress(String msg) {
        System.out.println(msg);

        try {
            int ret=System.in.read();
            System.in.skip(System.in.available());
            return ret;
        }
        catch(IOException e) {
            return 0;
        }
    }






    /** Returns a random value in the range [1 - range] */
    public static long random(long range) {
        return (long)((Math.random() * range) % range) + 1;
    }



    /** Sleeps between floor and ceiling milliseconds, chosen randomly */
    public static void sleepRandom(long floor, long ceiling) {
        if(ceiling - floor<= 0) {
            return;
        }
        long diff = ceiling - floor;
        long r=(int)((Math.random() * 100000) % diff) + floor;
        sleep(r);
    }


    /**
     Tosses a coin weighted with probability and returns true or false. Example: if probability=0.8,
     chances are that in 80% of all cases, true will be returned and false in 20%.
     */
    public static boolean tossWeightedCoin(double probability) {
        long r=random(100);
        long cutoff=(long)(probability * 100);
        return r < cutoff;
    }



    public static String dumpThreads() {
        StringBuilder sb=new StringBuilder();
        ThreadMXBean bean=ManagementFactory.getThreadMXBean();
        long[] ids=bean.getAllThreadIds();
        _printThreads(bean, ids, sb);
        long[] deadlocks=bean.findDeadlockedThreads();
        if(deadlocks != null && deadlocks.length > 0) {
            sb.append("deadlocked threads:\n");
            _printThreads(bean, deadlocks, sb);
        }

        deadlocks=bean.findMonitorDeadlockedThreads();
        if(deadlocks != null && deadlocks.length > 0) {
            sb.append("monitor deadlocked threads:\n");
            _printThreads(bean, deadlocks, sb);
        }
        return sb.toString();
    }


    protected static void _printThreads(ThreadMXBean bean, long[] ids, StringBuilder sb) {
        ThreadInfo[] threads=bean.getThreadInfo(ids, 20);
        for(int i=0; i < threads.length; i++) {
            ThreadInfo info=threads[i];
            if(info == null)
                continue;
            sb.append(info.getThreadName()).append(":\n");
            StackTraceElement[] stack_trace=info.getStackTrace();
            for(int j=0; j < stack_trace.length; j++) {
                StackTraceElement el=stack_trace[j];
                sb.append("    at ").append(el.getClassName()).append(".").append(el.getMethodName());
                sb.append("(").append(el.getFileName()).append(":").append(el.getLineNumber()).append(")");
                sb.append("\n");
            }
            sb.append("\n\n");
        }
    }


    public static boolean interruptAndWaitToDie(Thread t) {
        return interruptAndWaitToDie(t, Global.THREAD_SHUTDOWN_WAIT_TIME);
	}

    public static boolean interruptAndWaitToDie(Thread t, long timeout) {
        if(t == null)
            throw new IllegalArgumentException("Thread can not be null");
        t.interrupt(); // interrupts the sleep()
        try {
            t.join(timeout);
        }
        catch(InterruptedException e){
            Thread.currentThread().interrupt(); // set interrupt flag again
        }
        return t.isAlive();
	}


    /**
	 * Debugging method used to dump the content of a protocol queue in a
	 * condensed form. Useful to follow the evolution of the queue's content in
	 * time.
	 */
    public static String dumpQueue(Queue q) {
        StringBuilder sb=new StringBuilder();
        LinkedList values=q.values();
        if(values.isEmpty()) {
            sb.append("empty");
        }
        else {
            for(Object o: values) {
                String s=null;
                if(o instanceof Event) {
                    Event event=(Event)o;
                    int type=event.getType();
                    s=Event.type2String(type);
                    if(type == Event.VIEW_CHANGE)
                        s+=" " + event.getArg();
                    if(type == Event.MSG)
                        s+=" " + event.getArg();

                    if(type == Event.MSG) {
                        s+="[";
                        Message m=(Message)event.getArg();
                        Map<Short,Header> headers=new HashMap<Short,Header>(m.getHeaders());
                        for(Map.Entry<Short,Header> entry: headers.entrySet()) {
                            short id=entry.getKey();
                            Header value=entry.getValue();
                            String headerToString=null;
                            if(value instanceof FD.FdHeader) {
                                headerToString=value.toString();
                            }
                            else
                                if(value instanceof PingHeader) {
                                    headerToString=ClassConfigurator.getProtocol(id) + "-";
                                    if(((PingHeader)value).type == PingHeader.GET_MBRS_REQ) {
                                        headerToString+="GMREQ";
                                    }
                                    else
                                        if(((PingHeader)value).type == PingHeader.GET_MBRS_RSP) {
                                            headerToString+="GMRSP";
                                        }
                                        else {
                                            headerToString+="UNKNOWN";
                                        }
                                }
                                else {
                                    headerToString=ClassConfigurator.getProtocol(id) + "-" + (value == null ? "null" : value.toString());
                                }
                            s+=headerToString;
                            s+=" ";
                        }
                        s+="]";
                    }
                }
                else {
                    s=o.toString();
                }
                sb.append(s).append("\n");
            }
        }
        return sb.toString();
    }


    /**
     * Use with caution: lots of overhead
     */
    public static String printStackTrace(Throwable t) {
        StringWriter s=new StringWriter();
        PrintWriter p=new PrintWriter(s);
        t.printStackTrace(p);
        return s.toString();
    }

    public static String getStackTrace(Throwable t) {
        return printStackTrace(t);
    }



    public static String print(Throwable t) {
        return printStackTrace(t);
    }


    public static void crash() {
        System.exit(-1);
    }


    public static String printEvent(Event evt) {
        Message msg;

        if(evt.getType() == Event.MSG) {
            msg=(Message)evt.getArg();
            if(msg != null) {
                if(msg.getLength() > 0)
                    return printMessage(msg);
                else
                    return msg.printObjectHeaders();
            }
        }
        return evt.toString();
    }


    /** Tries to read an object from the message's buffer and prints it */
    public static String printMessage(Message msg) {
        if(msg == null)
            return "";
        if(msg.getLength() == 0)
            return null;

        try {
            return msg.getObject().toString();
        }
        catch(Exception e) {  // it is not an object
            return "";
        }
    }

    public static String mapToString(Map<? extends Object,? extends Object> map) {
        if(map == null)
            return "null";
        StringBuilder sb=new StringBuilder();
        for(Map.Entry<? extends Object,? extends Object> entry: map.entrySet()) {
            Object key=entry.getKey();
            Object val=entry.getValue();
            sb.append(key).append("=");
            if(val == null)
                sb.append("null");
            else
                sb.append(val);
            sb.append("\n");
        }
        return sb.toString();
    }




    public static void printThreads() {
        Thread threads[]=new Thread[Thread.activeCount()];
        Thread.enumerate(threads);
        System.out.println("------- Threads -------");
        for(int i=0; i < threads.length; i++) {
            System.out.println("#" + i + ": " + threads[i]);
        }
        System.out.println("------- Threads -------\n");
    }


    public static String activeThreads() {
        StringBuilder sb=new StringBuilder();
        Thread threads[]=new Thread[Thread.activeCount()];
        Thread.enumerate(threads);
        sb.append("------- Threads -------\n");
        for(int i=0; i < threads.length; i++) {
            sb.append("#").append(i).append(": ").append(threads[i]).append('\n');
        }
        sb.append("------- Threads -------\n");
        return sb.toString();
    }


    /**
     * MByte nowadays doesn't mean 1024 * 1024 bytes, but 1 million bytes, see http://en.wikipedia.org/wiki/Megabyte
     * @param bytes
     * @return
     */
    public static String printBytes(long bytes) {
        double tmp;

        if(bytes < 1000)
            return bytes + "b";
        if(bytes < 1000000) {
            tmp=bytes / 1000.0;
            return f.format(tmp) + "KB";
        }
        if(bytes < 1000000000) {
            tmp=bytes / 1000000.0;
            return f.format(tmp) + "MB";
        }
        else {
            tmp=bytes / 1000000000.0;
            return f.format(tmp) + "GB";
        }
    }


    public static String printTime(long time, TimeUnit unit) {
        long ns=TimeUnit.NANOSECONDS.convert(time, unit);
        long us=TimeUnit.MICROSECONDS.convert(time, unit);
        long ms=TimeUnit.MILLISECONDS.convert(time, unit);
        long secs=TimeUnit.SECONDS.convert(time, unit);

        if(secs > 0) return secs + "s";
        if(ms > 0) return ms + "ms";
        if(us > 0) return us + " us";
        return ns + "ns";
    }


    public static String format(double value) {
        return f.format(value);
    }


    public static long readBytesLong(String input) {
        Tuple<String,Long> tuple=readBytes(input);
        double num=Double.parseDouble(tuple.getVal1());
        return (long)(num * tuple.getVal2());
    }

    public static int readBytesInteger(String input) {
        Tuple<String,Long> tuple=readBytes(input);
        double num=Double.parseDouble(tuple.getVal1());
        return (int)(num * tuple.getVal2());
    }

    public static double readBytesDouble(String input) {
        Tuple<String,Long> tuple=readBytes(input);
        double num=Double.parseDouble(tuple.getVal1());
        return num * tuple.getVal2();
    }

    private static Tuple<String,Long> readBytes(String input) {
        input=input.trim().toLowerCase();

        int  index=-1;
        long factor=1;

        if((index=input.indexOf("k")) != -1)
            factor=1000;
        else if((index=input.indexOf("kb")) != -1)
            factor=1000;
        else if((index=input.indexOf("m")) != -1)
            factor=1000000;
        else if((index=input.indexOf("mb")) != -1)
            factor=1000000;
        else if((index=input.indexOf("g")) != -1)
            factor=1000000000;
        else if((index=input.indexOf("gb")) != -1)
            factor=1000000000;

        String str=index != -1? input.substring(0, index) : input;
        return new Tuple<String,Long>(str, factor);
    }

    public static String printBytes(double bytes) {
        double tmp;

        if(bytes < 1000)
            return bytes + "b";
        if(bytes < 1000000) {
            tmp=bytes / 1000.0;
            return f.format(tmp) + "KB";
        }
        if(bytes < 1000000000) {
            tmp=bytes / 1000000.0;
            return f.format(tmp) + "MB";
        }
        else {
            tmp=bytes / 1000000000.0;
            return f.format(tmp) + "GB";
        }
    }


    public static List<String> split(String input, int separator) {
        List<String> retval=new ArrayList<String>();
        if(input == null)
            return retval;
        int index=0, end;
        while(true) {
            index=input.indexOf(separator, index);
            if(index == -1)
                break;
            index++;
            end=input.indexOf(separator, index);
            if(end == -1)
                retval.add(input.substring(index));
            else
                retval.add(input.substring(index, end));
        }
        return retval;
    }


   /* public static String[] commands(String path, String separator) {
        if(path == null || path.length() == 0)
            return null;
        String[] tmp=path.split(separator + "+"); // multiple separators could be present
        if(tmp == null)
            return null;
        if(tmp.length == 0)
            return null;

        if(tmp[0].length() == 0) {
            tmp[0]=separator;
            if(tmp.length > 1) {
                String[] retval=new String[tmp.length -1];
                retval[0]=tmp[0] + tmp[1];
                System.arraycopy(tmp, 2, retval, 1, tmp.length-2);
                return retval;
            }
            return tmp;
        }
        return tmp;
    }*/


     public static String[] components(String path, String separator) {
        if(path == null || path.length() == 0)
            return null;
        String[] tmp=path.split(separator + "+"); // multiple separators could be present
        if(tmp == null)
            return null;
        if(tmp.length == 0)
            return null;

        if(tmp[0].length() == 0)
            tmp[0]=separator;
        return tmp;
    }

    /**
     Fragments a byte buffer into smaller fragments of (max.) frag_size.
     Example: a byte buffer of 1024 bytes and a frag_size of 248 gives 4 fragments
     of 248 bytes each and 1 fragment of 32 bytes.
     @return An array of byte buffers (<code>byte[]</code>).
     */
    public static byte[][] fragmentBuffer(byte[] buf, int frag_size, final int length) {
        byte[] retval[];
        int accumulated_size=0;
        byte[] fragment;
        int tmp_size=0;
        int num_frags;
        int index=0;

        num_frags=length % frag_size == 0 ? length / frag_size : length / frag_size + 1;
        retval=new byte[num_frags][];

        while(accumulated_size < length) {
            if(accumulated_size + frag_size <= length)
                tmp_size=frag_size;
            else
                tmp_size=length - accumulated_size;
            fragment=new byte[tmp_size];
            System.arraycopy(buf, accumulated_size, fragment, 0, tmp_size);
            retval[index++]=fragment;
            accumulated_size+=tmp_size;
        }
        return retval;
    }

    public static byte[][] fragmentBuffer(byte[] buf, int frag_size) {
        return fragmentBuffer(buf, frag_size, buf.length);
    }



    /**
     * Given a buffer and a fragmentation size, compute a list of fragmentation offset/length pairs, and
     * return them in a list. Example:<br/>
     * Buffer is 10 bytes, frag_size is 4 bytes. Return value will be ({0,4}, {4,4}, {8,2}).
     * This is a total of 3 fragments: the first fragment starts at 0, and has a length of 4 bytes, the second fragment
     * starts at offset 4 and has a length of 4 bytes, and the last fragment starts at offset 8 and has a length
     * of 2 bytes.
     * @param frag_size
     * @return List. A List<Range> of offset/length pairs
     */
    public static List<Range> computeFragOffsets(int offset, int length, int frag_size) {
        List<Range>   retval=new ArrayList<Range>();
        long   total_size=length + offset;
        int    index=offset;
        int    tmp_size=0;
        Range  r;

        while(index < total_size) {
            if(index + frag_size <= total_size)
                tmp_size=frag_size;
            else
                tmp_size=(int)(total_size - index);
            r=new Range(index, tmp_size);
            retval.add(r);
            index+=tmp_size;
        }
        return retval;
    }

    public static List<Range> computeFragOffsets(byte[] buf, int frag_size) {
        return computeFragOffsets(0, buf.length, frag_size);
    }

    /**
     Concatenates smaller fragments into entire buffers.
     @param fragments An array of byte buffers (<code>byte[]</code>)
     @return A byte buffer
     */
    public static byte[] defragmentBuffer(byte[] fragments[]) {
        int total_length=0;
        byte[] ret;
        int index=0;

        if(fragments == null) return null;
        for(int i=0; i < fragments.length; i++) {
            if(fragments[i] == null) continue;
            total_length+=fragments[i].length;
        }
        ret=new byte[total_length];
        for(int i=0; i < fragments.length; i++) {
            if(fragments[i] == null) continue;
            System.arraycopy(fragments[i], 0, ret, index, fragments[i].length);
            index+=fragments[i].length;
        }
        return ret;
    }


    public static void printFragments(byte[] frags[]) {
        for(int i=0; i < frags.length; i++)
            System.out.println('\'' + new String(frags[i]) + '\'');
    }


    public static byte[] encode(long num) {
        if(num == 0)
            return new byte[]{0};

        byte bytes_needed=numberOfBytesRequiredForLong(num);
        byte[] buf=new byte[bytes_needed + 1];
        buf[0]=bytes_needed;

        int index=1;
        for(int i=0; i < bytes_needed; i++)
            buf[index++]=getByteAt(num, i);
        return buf;
    }

    static protected byte getByteAt(long num, int index) {
        return (byte)((num >> (index * 8)));
    }

    public static long decode(byte[] buf) {
        if(buf[0] == 0)
            return 0;

        byte length=buf[0];
        return makeLong(buf, 1, length);
    }


    public static void writeLong(long num, DataOutput out) throws Exception {
        byte[] buf=encode(num);
        out.write(buf, 0, buf.length);
    }

    public static long readLong(DataInput in) throws Exception {
        byte len=in.readByte();
        if(len == 0)
            return 0;
        byte[] buf=new byte[len];
        in.readFully(buf, 0, len);
        return makeLong(buf, 0, len);
    }


    public static short makeShort(byte[] buf, int offset) {
        byte c1=buf[offset], c2=buf[offset+1];
        return  (short)((c1 << 8) + (c2 << 0));
    }

    static long makeLong(byte[] buf, int offset, int len) {
        long retval=0;
        for(int i=0; i < len; i++) {
            byte b=buf[offset + i];
            retval |= ((long)b & 0xff) << (i * 8);
        }
        return retval;
    }


    /**
     * Encode the highest delivered and received seqnos. The assumption is that the latter is always >= the former, and
     * highest received is not much higher than highest delivered.
     * @param highest_delivered
     * @param highest_received
     * @return
     */
    public static byte[] encodeLongSequence(long highest_delivered, long highest_received) {
        if(highest_received < highest_delivered)
            throw new IllegalArgumentException("highest_received (" + highest_received +
                                                 ") has to be >= highest_delivered (" + highest_delivered + ")");

        if(highest_delivered == 0 &&highest_received == 0)
            return new byte[]{0};

        long delta=highest_received - highest_delivered;

        // encode highest_delivered followed by delta
        byte num_bytes_for_hd=numberOfBytesRequiredForLong(highest_delivered),
          num_bytes_for_delta=numberOfBytesRequiredForLong(delta);

        byte[] buf=new byte[num_bytes_for_hd + num_bytes_for_delta + 1];

        buf[0]=encodeLength(num_bytes_for_hd, num_bytes_for_delta);

        int index=1;
        for(int i=0; i < num_bytes_for_hd; i++)
            buf[index++]=getByteAt(highest_delivered, i);

        for(int i=0; i < num_bytes_for_delta; i++)
            buf[index++]=getByteAt(delta, i);

        return buf;
    }

    private static byte numberOfBytesRequiredForLong(long number) {
        if(number >> 56 != 0) return 8;
        if(number >> 48 != 0) return 7;
        if(number >> 40 != 0) return 6;
        if(number >> 32 != 0) return 5;
        if(number >> 24 != 0) return 4;
        if(number >> 16 != 0) return 3;
        if(number >>  8 != 0) return 2;
        if(number != 0) return 1;
        return 1;
    }

    /** Returns true if all elements in the collection are the same */
    public static <T> boolean allEqual(Collection<T> elements) {
        if(elements.isEmpty())
            return false;
        Iterator<T> it=elements.iterator();
        T first=it.next();
        while(it.hasNext()) {
            T el=it.next();
            if(!el.equals(first))
                return false;
        }
        return true;
    }

    public static byte size(long number) {
        return (byte)(number == 0? 1 : numberOfBytesRequiredForLong(number) +1);
    }

    /**
     * Writes 2 longs, where the second long needs to be >= the first (we only write the delta !)
     * @param hd
     * @param hr
     * @return
     */
    public static byte size(long hd, long hr) {
        if(hd == 0 && hr == 0)
            return 1;

        byte num_bytes_for_hd=numberOfBytesRequiredForLong(hd),
          num_bytes_for_delta=numberOfBytesRequiredForLong(hr - hd);

        return (byte)(num_bytes_for_hd + num_bytes_for_delta + 1);
    }

    public static long[] decodeLongSequence(byte[] buf) {
        if(buf[0] == 0)
            return new long[]{0,0};

        byte[] lengths=decodeLength(buf[0]);
        long[] seqnos=new long[2];
        seqnos[0]=makeLong(buf, 1, lengths[0]);
        seqnos[1]=makeLong(buf, 1 + lengths[0], lengths[1]) + seqnos[0];

        return seqnos;
    }


    public static void writeLongSequence(long highest_delivered, long highest_received, DataOutput out) throws Exception {
        byte[] buf=encodeLongSequence(highest_delivered, highest_received);
        out.write(buf, 0, buf.length);
    }


    public static long[] readLongSequence(DataInput in) throws Exception {
        byte len=in.readByte();
        if(len == 0)
            return new long[]{0,0};

        byte[] lengths=decodeLength(len);
        long[] seqnos=new long[2];
        byte[] buf=new byte[lengths[0] + lengths[1]];
        in.readFully(buf, 0, buf.length);
        seqnos[0]=makeLong(buf, 0, lengths[0]);
        seqnos[1]=makeLong(buf, lengths[0], lengths[1]) + seqnos[0];
        return seqnos;
    }


    /**
     * Encodes the number of bytes needed into a single byte. The first number is encoded in the first nibble (the
     * first 4 bits), the second number in the second nibble
     * @param len1 The number of bytes needed to store a long. Must be between 0 and 8
     * @param len2 The number of bytes needed to store a long. Must be between 0 and 8
     * @return The byte storing the 2 numbers len1 and len2
     */
    public static byte encodeLength(byte len1, byte len2) {
        byte retval=len2;
        retval |= (len1 << 4);
        return retval;
    }

    public static byte[] decodeLength(byte len) {
        byte[] retval={(byte)0,(byte)0};
        retval[0]=(byte)((len & 0xff) >> 4);
        retval[1]=(byte)(len & ~0xf0); // 0xff is the first nibble set (11110000)
        // retval[1]=(byte)(len << 4);
        // retval[1]=(byte)((retval[1] & 0xff) >> 4);
        return retval;
    }


    public static <T> String printListWithDelimiter(Collection<T> list, String delimiter) {
        return printListWithDelimiter(list, delimiter, MAX_LIST_PRINT_SIZE);
    }


    public static <T> String printListWithDelimiter(Collection<T> list, String delimiter, int limit) {
        boolean first=true;
        StringBuilder sb=new StringBuilder();
        int count=0, size=list.size();
        for(T el: list) {
            if(first)
                first=false;
            else
                sb.append(delimiter);
            sb.append(el);
            if(limit > 0 && ++count >= limit) {
                if(size > count)
                    sb.append(" ..."); // .append(list.size()).append("...");
                break;
            }
        }
        return sb.toString();
    }

    public static <T> String printListWithDelimiter(T[] list, String delimiter, int limit) {
        boolean first=true;
        StringBuilder sb=new StringBuilder();
        int count=0, size=list.length;
        for(T el: list) {
            if(first)
                first=false;
            else
                sb.append(delimiter);
            sb.append(el);
            if(limit > 0 && ++count >= limit) {
                if(size > count)
                    sb.append(" ..."); // .append(list.length).append("...");
                break;
            }
        }
        return sb.toString();
    }


    public static <T> String printMapWithDelimiter(Map<T,T> map, String delimiter) {
        boolean first=true;
        StringBuilder sb=new StringBuilder();
        for(Map.Entry<T,T> entry: map.entrySet()) {
            if(first)
                first=false;
            else
                sb.append(delimiter);
            sb.append(entry.getKey()).append("=").append(entry.getValue());
        }
        return sb.toString();
    }




    public static String array2String(long[] array) {
        StringBuilder ret=new StringBuilder("[");

        if(array != null) {
            for(int i=0; i < array.length; i++)
                ret.append(array[i]).append(" ");
        }

        ret.append(']');
        return ret.toString();
    }

    public static String array2String(short[] array) {
        StringBuilder ret=new StringBuilder("[");

        if(array != null) {
            for(int i=0; i < array.length; i++)
                ret.append(array[i]).append(" ");
        }

        ret.append(']');
        return ret.toString();
    }

    public static String array2String(int[] array) {
        StringBuilder ret=new StringBuilder("[");

        if(array != null) {
            for(int i=0; i < array.length; i++)
                ret.append(array[i]).append(" ");
        }

        ret.append(']');
        return ret.toString();
    }

    public static String array2String(boolean[] array) {
        StringBuilder ret=new StringBuilder("[");

        if(array != null) {
            for(int i=0; i < array.length; i++)
                ret.append(array[i]).append(" ");
        }
        ret.append(']');
        return ret.toString();
    }

    public static String array2String(Object[] array) {
        return Arrays.toString(array);
    }

    /** Returns true if all elements of c match obj */
    public static boolean all(Collection c, Object obj) {
        for(Iterator iterator=c.iterator(); iterator.hasNext();) {
            Object o=iterator.next();
            if(!o.equals(obj))
                return false;
        }
        return true;
    }


    public static List<Address> leftMembers(Collection<Address> old_list, Collection<Address> new_list) {
        if(old_list == null || new_list == null)
            return null;
        List<Address> retval=new ArrayList<Address>(old_list);
        retval.removeAll(new_list);
        return retval;
    }

    public static List<Address> newMembers(List<Address> old_list, List<Address> new_list) {
        if(old_list == null || new_list == null)
            return null;
        List<Address> retval=new ArrayList<Address>(new_list);
        retval.removeAll(old_list);
        return retval;
    }

    public static <T> List<T> newElements(List<T> old_list, List<T> new_list) {
        if(new_list == null)
            return new ArrayList<T>();
        List<T> retval=new ArrayList<T>(new_list);
        if(old_list != null)
            retval.removeAll(old_list);
        return retval;
    }


    /**
     * Selects a random subset of members according to subset_percentage and returns them.
     * Picks no member twice from the same membership. If the percentage is smaller than 1 -> picks 1 member.
     */
    public static List<Address> pickSubset(List<Address> members, double subset_percentage) {
        List<Address> ret=new ArrayList<Address>(), tmp_mbrs;
        int num_mbrs=members.size(), subset_size, index;

        if(num_mbrs == 0) return ret;
        subset_size=(int)Math.ceil(num_mbrs * subset_percentage);

        tmp_mbrs=new ArrayList<Address>(members);

        for(int i=subset_size; i > 0 && !tmp_mbrs.isEmpty(); i--) {
            index=(int)((Math.random() * num_mbrs) % tmp_mbrs.size());
            ret.add(tmp_mbrs.get(index));
            tmp_mbrs.remove(index);
        }

        return ret;
    }


    public static <T> boolean contains(T key, T[] list) {
        if(list == null) return false;
        for(T tmp: list)
            if(tmp == key || tmp.equals(key))
                return true;
        return false;
    }


    public static boolean containsViewId(Collection<View> views, ViewId vid) {
        for(View view: views) {
            ViewId tmp=view.getViewId();
            if(tmp.equals(vid))
                return true;
        }
        return false;
    }

    public static boolean containsId(short id, short[] ids) {
        if(ids == null)
            return false;
        for(short tmp: ids)
            if(tmp == id)
                return true;
        return false;
    }


    public static List<View> detectDifferentViews(Map<Address,View> map) {
        final List<View> ret=new ArrayList<View>();
        for(View view: map.values()) {
            if(view == null)
                continue;
            ViewId vid=view.getViewId();
            if(!Util.containsViewId(ret, vid))
                ret.add(view);
        }
        return ret;
    }


    /**
     * Determines the members which take part in a merge. The resulting list consists of all merge coordinators
     * plus members outside a merge partition, e.g. for views A={B,A,C}, B={B,C} and C={B,C}, the merge coordinator
     * is B, but the merge participants are B and A.
     * @param map
     * @return
     */
    public static Collection<Address> determineMergeParticipants(Map<Address,View> map) {
        Set<Address> coords=new HashSet<Address>();
        Set<Address> all_addrs=new HashSet<Address>();

        if(map == null)
            return Collections.emptyList();

        for(View view: map.values())
            all_addrs.addAll(view.getMembers());

        for(View view: map.values()) {
            Address coord=view.getCreator();
            if(coord != null)
                coords.add(coord);
        }

        for(Address coord: coords) {
            View view=map.get(coord);
            Collection<Address> mbrs=view != null? view.getMembers() : null;
            if(mbrs != null)
                all_addrs.removeAll(mbrs);
        }
        coords.addAll(all_addrs);
        return coords;
    }


    /**
     * This is the same or a subset of {@link #determineMergeParticipants(java.util.Map)} and contains only members
     * which are currently sub-partition coordinators.
     * @param map
     * @return
     */
    public static Collection<Address> determineMergeCoords(Map<Address,View> map) {
        Set<Address> retval=new HashSet<Address>();
        if(map != null) {
            for(View view: map.values()) {
                Address coord=view.getCreator();
                if(coord != null)
                    retval.add(coord);
            }
        }
        return retval;
    }

    /**
     * Similar to {@link #determineMergeCoords(java.util.Map)} but only actual coordinators are counted: an actual
     * coord is when the sender of a view is the first member of that view
     * @param map
     * @return
     */
    public static Collection<Address> determineActualMergeCoords(Map<Address,View> map) {
        Set<Address> retval=new HashSet<Address>();
        if(map != null) {
            for(Map.Entry<Address,View> entry: map.entrySet()) {
                Address sender=entry.getKey();
                List<Address> members=entry.getValue().getMembers();
                Address actual_coord=members.isEmpty() ? null : members.get(0);
                if(sender.equals(actual_coord))
                    retval.add(sender);
            }
        }
        return retval;
    }


    /**
     * Returns the rank of a member in a given view
     * @param view The view
     * @param addr The address of a member
     * @return A value between 1 and view.size(). The first member has rank 1, the second 2 and so on. If the
     * member is not found, 0 is returned
     */
    public static int getRank(View view, Address addr) {
        if(view == null || addr == null)
            return 0;
        List<Address> members=view.getMembers();
        for(int i=0; i < members.size(); i++) {
            Address mbr=members.get(i);
            if(mbr.equals(addr))
                return i+1;
        }
        return 0;
    }

    public static int getRank(Collection<Address> members, Address addr) {
        if(members == null || addr == null)
            return -1;
        int index=0;
        for(Iterator<Address> it=members.iterator(); it.hasNext();) {
            Address mbr=it.next();
            if(mbr.equals(addr))
                return index+1;
            index++;
        }
        return -1;
    }


    public static <T> T pickRandomElement(List<T> list) {
            if(list == null) return null;
            int size=list.size();
            int index=(int)((Math.random() * size * 10) % size);
            return list.get(index);
        }

    public static Object pickRandomElement(Object[] array) {
        if(array == null) return null;
        int size=array.length;
        int index=(int)((Math.random() * size * 10) % size);
        return array[index];
    }

    /**
     * Returns the object next to element in list
     * @param list
     * @param obj
     * @param <T>
     * @return
     */
    public static <T> T pickNext(List<T> list, T obj) {
        if(list == null || obj == null)
            return null;
        Object[] array=list.toArray();
        for(int i=0; i < array.length; i++) {
            T tmp=(T)array[i];
            if(tmp != null && tmp.equals(obj))
                return (T)array[(i+1) % array.length];
        }
        return null;
    }

    /** Returns the next min(N,list.size()) elements after obj */
    public static <T> List<T> pickNext(List<T> list, T obj, int num) {
        List<T> retval=new ArrayList<T>();
        if(list == null || list.size() < 2)
            return retval;
        int index=list.indexOf(obj);
        if(index != -1) {
            for(int i=1; i <= num && i < list.size(); i++) {
                T tmp=list.get((index +i) % list.size());
                if(!retval.contains(tmp))
                    retval.add(tmp);
            }
        }
        return retval;
    }



    public static JChannel createChannel(Protocol... prots) throws Exception {
        JChannel ch=new JChannel(false);
        ProtocolStack stack=new ProtocolStack();
        ch.setProtocolStack(stack);
        for(Protocol prot: prots) {
            stack.addProtocol(prot);
            prot.setProtocolStack(stack);
        }
        stack.init();
        return ch;
    }


    public static Address createRandomAddress() {
        return createRandomAddress(generateLocalName());
    }

    /** Returns an array of num random addresses, named A, B, C etc */
    public static Address[] createRandomAddresses(int num) {
       return createRandomAddresses(num, false);
    }

    public static Address[] createRandomAddresses(int num, boolean use_numbers) {
        Address[] addresses=new Address[num];
        int number=1;
        char c='A';
        for(int i=0; i < addresses.length; i++)
            addresses[i]=Util.createRandomAddress(use_numbers? String.valueOf(number++) : String.valueOf(c++));
        return addresses;
    }

    public static Address createRandomAddress(String name) {
        UUID retval=UUID.randomUUID();
        UUID.add(retval, name);
        return retval;
    }

    public static Object[][] createTimer() {
        return new Object[][] {
          {new DefaultTimeScheduler(5)},
          {new TimeScheduler2()},
          {new TimeScheduler3()},
          {new HashedTimingWheel(5)}
        };
    }

    /**
     * Returns all members that left between 2 views. All members that are element of old_mbrs but not element of
     * new_mbrs are returned.
     */
    public static List<Address> determineLeftMembers(List<Address> old_mbrs, List<Address> new_mbrs) {
        List<Address> retval=new ArrayList<Address>();
        if(old_mbrs == null || new_mbrs == null)
            return retval;

        for(int i=0; i < old_mbrs.size(); i++) {
            Address mbr=old_mbrs.get(i);
            if(!new_mbrs.contains(mbr))
                retval.add(mbr);
        }
        return retval;
    }



    public static String printViews(Collection<View> views) {
        StringBuilder sb=new StringBuilder();
        boolean first=true;
        for(View view: views) {
            if(first)
                first=false;
            else
                sb.append(", ");
            sb.append(view.getViewId());
        }
        return sb.toString();
    }

   public static <T> String print(Collection<T> objs) {
        StringBuilder sb=new StringBuilder();
        boolean first=true;
        for(T obj: objs) {
            if(first)
                first=false;
            else
                sb.append(", ");
            sb.append(obj);
        }
        return sb.toString();
    }


    public static String print(byte[] array, int n) {
        StringBuilder sb=new StringBuilder();
        if(array != null) {
            for(int i=0; i < Math.min(n, array.length); i++)
                sb.append("'").append(array[i]).append("' ");
        }
        return sb.toString();
    }


    public static <T> String print(Map<T,T> map) {
        StringBuilder sb=new StringBuilder();
        boolean first=true;
        for(Map.Entry<T,T> entry: map.entrySet()) {
            if(first)
                first=false;
            else
                sb.append(", ");
            sb.append(entry.getKey()).append("=").append(entry.getValue());
        }
        return sb.toString();
    }



    public static String printPingData(List<PingData> rsps) {
        StringBuilder sb=new StringBuilder();
        if(rsps != null) {
            int total=rsps.size();
            int servers=0, clients=0, coords=0;
            for(PingData rsp: rsps) {
                if(rsp.isCoord())
                    coords++;
                if(rsp.isServer())
                    servers++;
                else
                    clients++;
            }
            sb.append(total + " total (" + servers + " servers (" + coords + " coord), " + clients + " clients)");
        }
        return sb.toString();
    }



    /**
    * if we were to register for OP_WRITE and send the remaining data on
    * readyOps for this channel we have to either block the caller thread or
    * queue the message buffers that may arrive while waiting for OP_WRITE.
    * Instead of the above approach this method will continuously write to the
    * channel until the buffer sent fully.
    */
    public static void writeFully(ByteBuffer buf, WritableByteChannel out) throws Exception {
        int written = 0;
        int toWrite = buf.limit();
        while (written < toWrite) {
            written += out.write(buf);
        }
    }



    /**
     * Tries to load the class from the current thread's context class loader. If
     * not successful, tries to load the class from the current instance.
     * @param classname Desired class.
     * @param clazz     Class object used to obtain a class loader
     *                  if no context class loader is available.
     * @return Class, or null on failure.
     */
    public static Class loadClass(String classname,Class clazz) throws ClassNotFoundException {
        return loadClass(classname, clazz.getClassLoader());
    }

    /**
     * Tries to load the class from the preferred loader.  If not successful, tries to
     * load the class from the current thread's context class loader or system class loader.
     * @param classname Desired class name.
     * @param preferredLoader The preferred class loader
     * @return the loaded class.
     * @throws ClassNotFoundException if the class could not be loaded by any loader
     */
    public static Class<?> loadClass(String classname, ClassLoader preferredLoader) throws ClassNotFoundException {
        ClassNotFoundException exception = null;
        for (ClassLoader loader: Arrays.asList(preferredLoader, Thread.currentThread().getContextClassLoader(), ClassLoader.getSystemClassLoader())) {
            try {
                return loader.loadClass(classname);
            } catch (ClassNotFoundException e) {
                if (exception == null) {
                    exception = e;
                }
            }
        }
        throw exception;
    }


    public static Field[] getAllDeclaredFields(final Class clazz) {
        return getAllDeclaredFieldsWithAnnotations(clazz);
    }

    public static Field[] getAllDeclaredFieldsWithAnnotations(final Class clazz, Class<? extends Annotation> ... annotations) {
        List<Field> list=new ArrayList<Field>(30);
        for(Class curr=clazz; curr != null; curr=curr.getSuperclass()) {
            Field[] fields=curr.getDeclaredFields();
            if(fields != null) {
                for(Field field: fields) {
                    if(annotations != null && annotations.length > 0) {
                        for(Class<? extends Annotation> annotation: annotations) {
                            if(field.isAnnotationPresent(annotation))
                                list.add(field);
                        }
                    }
                    else
                        list.add(field);
                }
            }
        }

        Field[] retval=new Field[list.size()];
        for(int i=0; i < list.size(); i++)
            retval[i]=list.get(i);
        return retval;
    }

    public static Method[] getAllDeclaredMethods(final Class clazz) {
        return getAllDeclaredMethodsWithAnnotations(clazz);
    }

    public static Method[] getAllDeclaredMethodsWithAnnotations(final Class clazz, Class<? extends Annotation> ... annotations) {
        List<Method> list=new ArrayList<Method>(30);
        for(Class curr=clazz; curr != null; curr=curr.getSuperclass()) {
            Method[] methods=curr.getDeclaredMethods();
            if(methods != null) {
                for(Method method: methods) {
                    if(annotations != null && annotations.length > 0) {
                        for(Class<? extends Annotation> annotation: annotations) {
                            if(method.isAnnotationPresent(annotation))
                                list.add(method);
                        }
                    }
                    else
                        list.add(method);
                }
            }
        }

        Method[] retval=new Method[list.size()];
        for(int i=0; i < list.size(); i++)
            retval[i]=list.get(i);
        return retval;
    }

    public static <A extends Annotation> A getAnnotation(Class<?> clazz, Class<A> annotationClass) {
        for(Class<?> curr=clazz; curr != null; curr=curr.getSuperclass()) {
            A ann=curr.getAnnotation(annotationClass);
            if(ann != null)
                return ann;
        }
        return null;
    }

    public static Field getField(final Class clazz, String field_name) {
        if(clazz == null || field_name == null)
            return null;

        Field field=null;
        for(Class curr=clazz; curr != null; curr=curr.getSuperclass()) {
            try {
                return curr.getDeclaredField(field_name);
            }
            catch(NoSuchFieldException e) {
            }
        }
        return field;
    }

    public static void setField(Field field, Object target, Object value) {
        if(!Modifier.isPublic(field.getModifiers())) {
            field.setAccessible(true);
        }
        try {
            field.set(target, value);
        }
        catch(IllegalAccessException iae) {
            throw new IllegalArgumentException("Could not set field " + field, iae);
        }
    }

    public static Object getField(Field field, Object target) {
        if(!Modifier.isPublic(field.getModifiers())) {
            field.setAccessible(true);
        }
        try {
            return field.get(target);
        }
        catch(IllegalAccessException iae) {
            throw new IllegalArgumentException("Could not get field " + field, iae);
        }
    }


    public static Field findField(Object target, List<String> possible_names) {
        if(target == null)
            return null;
        for(Class<?> clazz=target.getClass(); clazz != null; clazz=clazz.getSuperclass()) {
            for(String name: possible_names) {
                try {
                    return clazz.getDeclaredField(name);
                }
                catch(Exception e) {
                }
            }
        }
        return null;
    }


    public static Method findMethod(Object target, List<String> possible_names, Class<?> ... parameter_types) {
        if(target == null)
            return null;
        for(Class<?> clazz=target.getClass(); clazz != null; clazz=clazz.getSuperclass()) {
            for(String name: possible_names) {
                try {
                    return clazz.getDeclaredMethod(name, parameter_types);
                }
                catch(Exception e) {
                }
            }
        }
        return null;
    }



    public static <T> Set<Class<T>> findClassesAssignableFrom(String packageName, Class<T> assignableFrom)
      throws IOException, ClassNotFoundException {
        ClassLoader loader = Thread.currentThread().getContextClassLoader();
        Set<Class<T>> classes = new HashSet<Class<T>>();
        String path = packageName.replace('.', '/');
        URL resource = loader.getResource(path);
        if (resource != null) {
            String filePath = resource.getFile();
            if (filePath != null && new File(filePath).isDirectory()) {
                for (String file : new File(filePath).list()) {
                    if (file.endsWith(".class")) {
                        String name = packageName + '.' + file.substring(0, file.indexOf(".class"));
                        Class<T> clazz =(Class<T>)Class.forName(name);
                        if (assignableFrom.isAssignableFrom(clazz))
                            classes.add(clazz);
                    }
                }
            }
        }
        return classes;
    }

    public static List<Class<?>> findClassesAnnotatedWith(String packageName, Class<? extends Annotation> a) throws IOException, ClassNotFoundException {
        List<Class<?>> classes = new ArrayList<Class<?>>();
        recurse(classes, packageName, a);
        return classes;
    }

    private static void recurse(List<Class<?>> classes, String packageName, Class<? extends Annotation> a) throws ClassNotFoundException {
        ClassLoader loader = Thread.currentThread().getContextClassLoader();
        String path = packageName.replace('.', '/');
        URL resource = loader.getResource(path);
        if (resource != null) {
            String filePath = resource.getFile();
            if (filePath != null && new File(filePath).isDirectory()) {
                for (String file : new File(filePath).list()) {
                    if (file.endsWith(".class")) {
                        String name = packageName + '.' + file.substring(0, file.indexOf(".class"));
                        Class<?> clazz = Class.forName(name);
                        if (clazz.isAnnotationPresent(a))
                            classes.add(clazz);
                    }
                    else if (new File(filePath,file).isDirectory()) {
                        recurse(classes, packageName + "." + file, a);
                    }
                }
            }
        }
    }


    public static InputStream getResourceAsStream(String name, Class clazz) {
        ClassLoader loader;
        InputStream retval=null;

        // https://issues.jboss.org/browse/JGRP-1762: load the classloader from the defining class first
        if(clazz != null) {
            try {
                loader=clazz.getClassLoader();
                if(loader != null) {
                    retval=loader.getResourceAsStream(name);
                    if(retval != null)
                        return retval;
                }
            }
            catch(Throwable t) {
            }
        }

        try {
            loader=Thread.currentThread().getContextClassLoader();
            if(loader != null) {
                retval=loader.getResourceAsStream(name);
                if(retval != null)
                    return retval;
            }
        }
        catch(Throwable t) {
        }

        try {
            loader=ClassLoader.getSystemClassLoader();
            if(loader != null) {
                return loader.getResourceAsStream(name);
            }
        }
        catch(Throwable t) {
        }

        return retval;
    }


    /** Checks whether 2 Addresses are on the same host */
    public static boolean sameHost(Address one, Address two) {
        InetAddress a, b;
        String host_a, host_b;

        if(one == null || two == null) return false;
        if(!(one instanceof IpAddress) || !(two instanceof IpAddress)) {
            return false;
        }

        a=((IpAddress)one).getIpAddress();
        b=((IpAddress)two).getIpAddress();
        if(a == null || b == null) return false;
        host_a=a.getHostAddress();
        host_b=b.getHostAddress();

        // System.out.println("host_a=" + host_a + ", host_b=" + host_b);
        return host_a.equals(host_b);
    }



    public static boolean fileExists(String fname) {
        return (new File(fname)).exists();
    }

    public static void verifyRejectionPolicy(String str) throws Exception{
        if(!(str.equalsIgnoreCase("run") || str.equalsIgnoreCase("abort")|| str.equalsIgnoreCase("discard")|| str.equalsIgnoreCase("discardoldest"))) {
            throw new Exception("Unknown rejection policy " + str);
        }
    }

    public static RejectedExecutionHandler parseRejectionPolicy(String rejection_policy) {
        if(rejection_policy == null)
            throw new IllegalArgumentException("rejection policy is null");
        if(rejection_policy.equalsIgnoreCase("abort"))
            return new ThreadPoolExecutor.AbortPolicy();
        if(rejection_policy.equalsIgnoreCase("discard"))
            return new ThreadPoolExecutor.DiscardPolicy();
        if(rejection_policy.equalsIgnoreCase("discardoldest"))
            return new ThreadPoolExecutor.DiscardOldestPolicy();
        if(rejection_policy.equalsIgnoreCase("run"))
            return new ThreadPoolExecutor.CallerRunsPolicy();
        if(rejection_policy.toLowerCase().startsWith(CustomRejectionPolicy.NAME))
            return new CustomRejectionPolicy(rejection_policy);
        if(rejection_policy.toLowerCase().startsWith(ProgressCheckRejectionPolicy.NAME))
            return new ProgressCheckRejectionPolicy(rejection_policy);
        throw new IllegalArgumentException("rejection policy \"" + rejection_policy + "\" not known");
    }


    /**
     * Parses comma-delimited longs; e.g., 2000,4000,8000.
     * Returns array of long, or null.
     */
    public static int[] parseCommaDelimitedInts(String s) {
        StringTokenizer tok;
        List<Integer> v=new ArrayList<Integer>();
        Integer l;
        int[] retval=null;

        if(s == null) return null;
        tok=new StringTokenizer(s, ",");
        while(tok.hasMoreTokens()) {
            l=new Integer(tok.nextToken());
            v.add(l);
        }
        if(v.isEmpty()) return null;
        retval=new int[v.size()];
        for(int i=0; i < v.size(); i++)
            retval[i]=v.get(i).intValue();
        return retval;
    }

    /**
     * Parses comma-delimited longs; e.g., 2000,4000,8000.
     * Returns array of long, or null.
     */
    public static long[] parseCommaDelimitedLongs(String s) {
        StringTokenizer tok;
        List<Long> v=new ArrayList<Long>();
        Long l;
        long[] retval=null;

        if(s == null) return null;
        tok=new StringTokenizer(s, ",");
        while(tok.hasMoreTokens()) {
            l=new Long(tok.nextToken());
            v.add(l);
        }
        if(v.isEmpty()) return null;
        retval=new long[v.size()];
        for(int i=0; i < v.size(); i++)
            retval[i]=v.get(i).longValue();
        return retval;
    }

    /** e.g. "bela,jeannette,michelle" --> List{"bela", "jeannette", "michelle"} */
    public static List<String> parseCommaDelimitedStrings(String l) {
        return parseStringList(l, ",");
    }

    /**
     * Input is "daddy[8880],sindhu[8880],camille[5555]. Returns a list of IpAddresses
     */
    public static List<IpAddress> parseCommaDelimitedHosts(String hosts, int port_range) throws UnknownHostException {
        StringTokenizer tok=new StringTokenizer(hosts, ",");
        String t;
        IpAddress addr;
        Set<IpAddress> retval=new HashSet<IpAddress>();

        while(tok.hasMoreTokens()) {
            t=tok.nextToken().trim();
            String host=t.substring(0, t.indexOf('['));
            host=host.trim();
            int port=Integer.parseInt(t.substring(t.indexOf('[') + 1, t.indexOf(']')));
            for(int i=port;i <= port + port_range;i++) {
                addr=new IpAddress(host, i);
                retval.add(addr);
            }
        }
        return new LinkedList<IpAddress>(retval);
    }


    /**
     * Input is "daddy[8880],sindhu[8880],camille[5555]. Return List of
     * InetSocketAddress
     */
    public static List<InetSocketAddress> parseCommaDelimitedHosts2(String hosts, int port_range) {

        StringTokenizer tok=new StringTokenizer(hosts, ",");
        String t;
        InetSocketAddress addr;
        Set<InetSocketAddress> retval=new HashSet<InetSocketAddress>();

        while(tok.hasMoreTokens()) {
            t=tok.nextToken().trim();
            String host=t.substring(0, t.indexOf('['));
            host=host.trim();
            int port=Integer.parseInt(t.substring(t.indexOf('[') + 1, t.indexOf(']')));
            for(int i=port;i < port + port_range;i++) {
                addr=new InetSocketAddress(host, i);
                retval.add(addr);
            }
        }
        return new LinkedList<InetSocketAddress>(retval);
   }

    public static List<String> parseStringList(String l, String separator) {
         List<String> tmp=new LinkedList<String>();
         StringTokenizer tok=new StringTokenizer(l, separator);
         String t;

         while(tok.hasMoreTokens()) {
             t=tok.nextToken();
             tmp.add(t.trim());
         }

         return tmp;
     }

    public static Map<String, String> parseCommaDelimitedProps(String s) {
        if (s == null) {
            return null;
        }
        Map<String, String> props = new HashMap<String, String>();
        Pattern p = Pattern.compile("\\s*([^=\\s]+)\\s*=\\s*([^=\\s,]+)\\s*,?"); //Pattern.compile("\\s*([^=\\s]+)\\s*=\\s([^=\\s]+)\\s*,?");
        Matcher matcher = p.matcher(s);
        while(matcher.find()) {
            props.put(matcher.group(1), matcher.group(2));
        }
        return props;
    }


    public static String parseString(ByteBuffer buf) {
        return parseString(buf, true);
    }


    public static String parseString(ByteBuffer buf, boolean discard_whitespace) {
        StringBuilder sb=new StringBuilder();
        char ch;

        // read white space
        while(buf.remaining() > 0) {
            ch=(char)buf.get();
            if(!Character.isWhitespace(ch)) {
                buf.position(buf.position() -1);
                break;
            }
        }

        if(buf.remaining() == 0)
            return null;

        while(buf.remaining() > 0) {
            ch=(char)buf.get();
            if(!Character.isWhitespace(ch)) {
                sb.append(ch);
            }
            else
                break;
        }

        // read white space
        if(discard_whitespace) {
            while(buf.remaining() > 0) {
                ch=(char)buf.get();
                if(!Character.isWhitespace(ch)) {
                    buf.position(buf.position() -1);
                    break;
                }
            }
        }
        return sb.toString();
    }

    public static int readNewLine(ByteBuffer buf) {
        char ch;
        int num=0;

        while(buf.remaining() > 0) {
            ch=(char)buf.get();
            num++;
            if(ch == '\n')
                break;
        }
        return num;
    }


    /**
     * Reads and discards all characters from the input stream until a \r\n or EOF is encountered
     * @param in
     * @return
     */
    public static int discardUntilNewLine(InputStream in) {
        int ch;
        int num=0;

        while(true) {
            try {
                ch=in.read();
                if(ch == -1)
                    break;
                num++;
                if(ch == '\n')
                    break;
            }
            catch(IOException e) {
                break;
            }
        }
        return num;
    }

    /**
     * Reads a line of text.  A line is considered to be terminated by any one
     * of a line feed ('\n'), a carriage return ('\r'), or a carriage return
     * followed immediately by a linefeed.
     *
     *  @return     A String containing the contents of the line, not including
     *             any line-termination characters, or null if the end of the
     *             stream has been reached
     *
     * @exception  IOException  If an I/O error occurs
     */
    public static String readLine(InputStream in) throws IOException {
        StringBuilder sb=new StringBuilder(35);
        int ch;

        while(true) {
            ch=in.read();
            if(ch == -1)
                return null;
            if(ch == '\r') {
                ;
            }
            else {
                if(ch == '\n')
                    break;
                else {
                    sb.append((char)ch);
                }
            }
        }
        return sb.toString();
    }


    public static void writeString(ByteBuffer buf, String s) {
        for(int i=0; i < s.length(); i++)
            buf.put((byte)s.charAt(i));
    }


    /**
     *
     * @param s
     * @return List<NetworkInterface>
     */
    public static List<NetworkInterface> parseInterfaceList(String s) throws Exception {
        List<NetworkInterface> interfaces=new ArrayList<NetworkInterface>(10);
        if(s == null)
            return null;

        StringTokenizer tok=new StringTokenizer(s, ",");
        String interface_name;
        NetworkInterface intf;

        while(tok.hasMoreTokens()) {
            interface_name=tok.nextToken();

            // try by name first (e.g. (eth0")
            intf=NetworkInterface.getByName(interface_name);

            // next try by IP address or symbolic name
            if(intf == null)
                intf=NetworkInterface.getByInetAddress(InetAddress.getByName(interface_name));

            if(intf == null)
                throw new Exception("interface " + interface_name + " not found");
            if(!interfaces.contains(intf)) {
                interfaces.add(intf);
            }
        }
        return interfaces;
    }


    public static String print(List<NetworkInterface> interfaces) {
        StringBuilder sb=new StringBuilder();
        boolean first=true;

        for(NetworkInterface intf: interfaces) {
            if(first) {
                first=false;
            }
            else {
                sb.append(", ");
            }
            sb.append(intf.getName());
        }
        return sb.toString();
    }


    public static String shortName(String hostname) {
        if(hostname == null) return null;

        int index=hostname.indexOf('.');
        if(index > 0 && !Character.isDigit(hostname.charAt(0)))
            return hostname.substring(0, index);
        else
            return hostname;
    }

    public static boolean startFlush(Channel c, List<Address> flushParticipants,
            int numberOfAttempts, long randomSleepTimeoutFloor, long randomSleepTimeoutCeiling) {
      int attemptCount = 0;
      while (attemptCount < numberOfAttempts) {
         try {
            c.startFlush(flushParticipants, false);
            return true;
         } catch (Exception e) {
            Util.sleepRandom(randomSleepTimeoutFloor, randomSleepTimeoutCeiling);
            attemptCount++;
         }
      }
      return false;
    }

    public static boolean startFlush(Channel c, List<Address> flushParticipants) {
    	return startFlush(c,flushParticipants,4,1000,5000);
    }

    public static boolean startFlush(Channel c, int numberOfAttempts, long randomSleepTimeoutFloor,long randomSleepTimeoutCeiling) {
        int attemptCount = 0;
        while(attemptCount < numberOfAttempts){
            try{
               c.startFlush(false);
               return true;
            } catch(Exception e) {
               Util.sleepRandom(randomSleepTimeoutFloor,randomSleepTimeoutCeiling);
               attemptCount++;
            }
        }
        return false;
    }

    public static boolean startFlush(Channel c) {
    	return startFlush(c,4,1000,5000);
    }

    public static String shortName(InetAddress hostname) {
        if(hostname == null) return null;
        StringBuilder sb=new StringBuilder();
        if(resolve_dns)
            sb.append(hostname.getHostName());
        else
            sb.append(hostname.getHostAddress());
        return sb.toString();
    }

    public static String generateLocalName() {
        String retval=null;
        try {
            retval=shortName(InetAddress.getLocalHost().getHostName());
        }
        catch(Throwable e) {
        }
        if(retval == null) {
            try {
                retval=shortName(InetAddress.getByName(null).getHostName());
            }
            catch(Throwable e) {
                retval="localhost";
            }
        }

        long counter=Util.random(Short.MAX_VALUE *2);
        return retval + "-" + counter;
    }




    public synchronized static short incrCounter() {
        short retval=COUNTER++;
        if(COUNTER >= Short.MAX_VALUE)
            COUNTER=1;
        return retval;
    }


    public static <K,V> ConcurrentMap<K,V> createConcurrentMap(int initial_capacity, float load_factor, int concurrency_level) {
        return new ConcurrentHashMap<K,V>(initial_capacity, load_factor, concurrency_level);
    }

    public static <K,V> ConcurrentMap<K,V> createConcurrentMap(int initial_capacity) {
        return new ConcurrentHashMap<K,V>(initial_capacity);
    }

    public static <K,V> ConcurrentMap<K,V> createConcurrentMap() {
        return new ConcurrentHashMap<K,V>(CCHM_INITIAL_CAPACITY, CCHM_LOAD_FACTOR, CCHM_CONCURRENCY_LEVEL);
    }

    public static <K,V> Map<K,V> createHashMap() {
        return new HashMap<K,V>(CCHM_INITIAL_CAPACITY, CCHM_LOAD_FACTOR);
    }




    public static ServerSocket createServerSocket(SocketFactory factory, String service_name, InetAddress bind_addr, int start_port) {
        ServerSocket ret=null;

        while(true) {
            try {
                ret=factory.createServerSocket(service_name, start_port, 50, bind_addr);
            }
            catch(BindException bind_ex) {
                start_port++;
                continue;
            }
            catch(IOException io_ex) {
            }
            break;
        }
        return ret;
    }


    /**
     * Finds first available port starting at start_port and returns server
     * socket. Will not bind to port >end_port. Sets srv_port
     */
    public static ServerSocket createServerSocket(SocketFactory factory, String service_name, InetAddress bind_addr,
                                                  int start_port, int end_port) throws Exception {
        ServerSocket ret=null;
        int original_start_port=start_port;

        while(true) {
            try {
                if(bind_addr == null)
                    ret=factory.createServerSocket(service_name, start_port);
                else {
                    // changed (bela Sept 7 2007): we accept connections on all NICs
                    ret=factory.createServerSocket(service_name, start_port, 50, bind_addr);
                }
            }
            catch(SocketException bind_ex) {
                if(start_port == end_port)
                    throw new BindException("No available port to bind to in range [" + original_start_port + " .. " + end_port + "]");
                if(bind_addr != null && !bind_addr.isLoopbackAddress()) {
                    NetworkInterface nic=NetworkInterface.getByInetAddress(bind_addr);
                    if(nic == null)
                        throw new BindException("bind_addr " + bind_addr + " is not a valid interface: " + bind_ex);
                }
                start_port++;
                continue;
            }
            break;
        }
        return ret;
    }




    /**
     * Creates a DatagramSocket bound to addr. If addr is null, socket won't be bound. If address is already in use,
     * start_port will be incremented until a socket can be created.
     * @param addr The InetAddress to which the socket should be bound. If null, the socket will not be bound.
     * @param port The port which the socket should use. If 0, a random port will be used. If > 0, but port is already
     *             in use, it will be incremented until an unused port is found, or until MAX_PORT is reached.
     */
    public static DatagramSocket createDatagramSocket(SocketFactory factory, String service_name, InetAddress addr, int port) throws Exception {
        DatagramSocket sock=null;

        if(addr == null) {
            if(port == 0) {
                return factory.createDatagramSocket(service_name);
            }
            else {
                while(port < MAX_PORT) {
                    try {
                        return factory.createDatagramSocket(service_name, port);
                    }
                    catch(BindException bind_ex) { // port already used
                        port++;
                    }
                }
            }
        }
        else {
            if(port == 0) port=1024;
            while(port < MAX_PORT) {
                try {
                    return factory.createDatagramSocket(service_name, port, addr);
                }
                catch(BindException bind_ex) { // port already used
                    port++;
                }
            }
        }
        return sock; // will never be reached, but the stupid compiler didn't figure it out...
    }



    public static MulticastSocket createMulticastSocket(SocketFactory factory, String service_name, InetAddress mcast_addr, int port, Log log) throws IOException {
        if(mcast_addr != null && !mcast_addr.isMulticastAddress())
            throw new IllegalArgumentException("mcast_addr (" + mcast_addr + ") is not a valid multicast address");

        SocketAddress saddr=new InetSocketAddress(mcast_addr, port);
        MulticastSocket retval=null;

        try {
            retval=factory.createMulticastSocket(service_name, saddr);
        }
        catch(IOException ex) {
            if(log != null && log.isWarnEnabled()) {
                StringBuilder sb=new StringBuilder();
                String type=mcast_addr != null ? mcast_addr instanceof Inet4Address? "IPv4" : "IPv6" : "n/a";
                sb.append("could not bind to " + mcast_addr + " (" + type + " address)");
                sb.append("; make sure your mcast_addr is of the same type as the preferred IP stack (IPv4 or IPv6)");
                sb.append(" by checking the value of the system properties java.net.preferIPv4Stack and java.net.preferIPv6Addresses.");
                sb.append("\nWill ignore mcast_addr, but this may lead to cross talking " +
                        "(see http://www.jboss.org/community/docs/DOC-9469 for details). ");
                sb.append("\nException was: " + ex);
                log.warn(sb.toString());
            }
        }
        if(retval == null)
            retval=factory.createMulticastSocket(service_name, port);
        return retval;
    }



    /**
     * Method used by PropertyConverters.BindInterface to check that a bind_address is
     * consistent with a specified interface
     *
     * Idea:
     * 1. We are passed a bind_addr, which may be null
     * 2. If non-null, check that bind_addr is on bind_interface - if not, throw exception,
     * otherwise, return the original bind_addr
     * 3. If null, get first non-loopback address on bind_interface, using stack preference to
     * get the IP version. If no non-loopback address, then just return null (i.e. the
     * bind_interface did not influence the decision).
     *
     */
    public static InetAddress validateBindAddressFromInterface(InetAddress bind_addr, String bind_interface_str) throws UnknownHostException, SocketException {
    	NetworkInterface bind_intf=null;

        if(bind_addr != null && bind_addr.isLoopbackAddress())
            return bind_addr;

    	// 1. if bind_interface_str is null, or empty, no constraint on bind_addr
    	if (bind_interface_str == null || bind_interface_str.trim().length() == 0)
    		return bind_addr;

    	// 2. get the preferred IP version for the JVM - it will be IPv4 or IPv6
    	StackType ip_version = getIpStackType();

    	// 3. if bind_interface_str specified, get interface and check that it has correct version
    	bind_intf=NetworkInterface.getByName(bind_interface_str);
    	if(bind_intf != null) {
            // check that the interface supports the IP version
            boolean supportsVersion = interfaceHasIPAddresses(bind_intf, ip_version) ;
            if (!supportsVersion)
                throw new IllegalArgumentException("bind_interface " + bind_interface_str + " has incorrect IP version") ;
        }
        else {
    		// (bind_intf == null)
    		throw new UnknownHostException("network interface " + bind_interface_str + " not found");
    	}

    	// 3. intf and bind_addr are both are specified, bind_addr needs to be on intf
    	if (bind_addr != null) {

    		boolean hasAddress = false ;

    		// get all the InetAddresses defined on the interface
    		Enumeration addresses = bind_intf.getInetAddresses() ;

    		while (addresses != null && addresses.hasMoreElements()) {
    			// get the next InetAddress for the current interface
    			InetAddress address = (InetAddress) addresses.nextElement() ;

    			// check if address is on interface
    			if (bind_addr.equals(address)) {
    				hasAddress = true ;
    				break ;
    			}
    		}

    		if (!hasAddress) {
    			String bind_addr_str = bind_addr.getHostAddress();
    			throw new IllegalArgumentException("network interface " + bind_interface_str + " does not contain address " + bind_addr_str);
    		}

    	}
    	// 4. if only interface is specified, get first non-loopback address on that interface,
    	else {
    		bind_addr = getAddress(bind_intf, AddressScope.NON_LOOPBACK) ;
    	}


    	//http://jira.jboss.org/jira/browse/JGRP-739
    	//check all bind_address against NetworkInterface.getByInetAddress() to see if it exists on the machine
    	//in some Linux setups NetworkInterface.getByInetAddress(InetAddress.getLocalHost()) returns null, so skip
    	//the check in that case
    	if(bind_addr != null && NetworkInterface.getByInetAddress(bind_addr) == null) {
    		throw new UnknownHostException("Invalid bind address " + bind_addr);
    	}

    	// if bind_addr == null, we have tried to obtain a bind_addr but were not successful
    	// in such a case, return the original value of null so the default will be applied

    	return bind_addr;
    }


    public static boolean checkForLinux() {
        return checkForPresence("os.name", "linux");
    }

    public static boolean checkForHp() {
       return checkForPresence("os.name", "hp");
    }

    public static boolean checkForSolaris() {
        return checkForPresence("os.name", "sun");
    }

    public static boolean checkForWindows() {
        return checkForPresence("os.name", "win");
    }

    public static boolean checkForMac() {
        return checkForPresence("os.name", "mac");
    }

    public static boolean checkForAndroid() {
        return contains("java.vm.vendor", "android");
    }

    private static boolean checkForPresence(String key, String value) {
        try {
            String tmp=System.getProperty(key);
            return tmp != null && tmp.trim().toLowerCase().startsWith(value);
        }
        catch(Throwable t) {
            return false;
        }
    }

    private static boolean contains(String key, String value) {
        try {
            String tmp=System.getProperty(key);
            return tmp != null && tmp.trim().toLowerCase().contains(value.trim().toLowerCase());
        }
        catch(Throwable t) {
            return false;
        }
    }



    public static void prompt(String s) {
        System.out.println(s);
        System.out.flush();
        try {
            while(System.in.available() > 0)
                System.in.read();
            System.in.read();
        }
        catch(IOException e) {
            e.printStackTrace();
        }
    }



    /** IP related utilities */
    public static InetAddress getLocalhost(StackType ip_version) throws UnknownHostException {
    	if (ip_version == StackType.IPv4)
    		return InetAddress.getByName("127.0.0.1") ;
    	else
    		return InetAddress.getByName("::1") ;
    }



    /**
     * Returns the first non-loopback address on any interface on the current host.
     */
    public static InetAddress getNonLoopbackAddress() throws SocketException {
        return getAddress(AddressScope.NON_LOOPBACK);
    }



    /**
     * Returns the first address on any interface of the current host, which satisfies scope
     */
    public static InetAddress getAddress(AddressScope scope) throws SocketException {
        InetAddress address=null ;

        Enumeration intfs=NetworkInterface.getNetworkInterfaces();
        while(intfs.hasMoreElements()) {
            NetworkInterface intf=(NetworkInterface)intfs.nextElement();
            try {
                if(intf.isUp()) {
                    address=getAddress(intf, scope) ;
                    if(address != null)
                        return address;
                }
            }
            catch (SocketException e) {
            }
        }
        return null ;
    }

    /**
     * Returns a valid interface address based on a pattern. Iterates over all interfaces that are up and
     * returns the first match, based on the address or interface name
     * @param pattern Can be "match-addr:<pattern></pattern>" or "match-interface:<pattern></pattern>". Example:<p/>
     *                match-addr:192.168.*
     * @return InetAddress or null if not found
     */
    public static InetAddress getAddressByPatternMatch(String pattern) throws Exception {
        if(pattern == null) return null;
        String  real_pattern=null;
        byte type=0; // 1=match-interface, 2: match-addr, 3: match-host,

        if(pattern.startsWith(Global.MATCH_INTF)) {
            type=1;
            real_pattern=pattern.substring(Global.MATCH_INTF.length() +1);
        }
        else if(pattern.startsWith(Global.MATCH_ADDR)) {
            type=2;
            real_pattern=pattern.substring(Global.MATCH_ADDR.length() +1);
        }
        else if(pattern.startsWith(Global.MATCH_HOST)) {
            type=3;
            real_pattern=pattern.substring(Global.MATCH_HOST.length() +1);
        }

        if(real_pattern == null)
            throw new IllegalArgumentException("expected " + Global.MATCH_ADDR + ":<pattern>, " +
                                                 Global.MATCH_HOST + ":<pattern> or " + Global.MATCH_INTF + ":<pattern>");

        Pattern pat=Pattern.compile(real_pattern);
        Enumeration intfs=NetworkInterface.getNetworkInterfaces();
        while(intfs.hasMoreElements()) {
            NetworkInterface intf=(NetworkInterface)intfs.nextElement();
            try {
                if(!intf.isUp())
                    continue;
                switch(type) {
                    case 1: // match by interface name
                        String interface_name=intf.getName();
                        Matcher matcher=pat.matcher(interface_name);
                        if(matcher.matches())
                            return getAddress(intf, null);
                        break;
                    case 2: // match by host address
                    case 3: // match by host name
                        for(Enumeration<InetAddress> en=intf.getInetAddresses(); en.hasMoreElements();) {
                            InetAddress addr=en.nextElement();
                            String name=type == 3? addr.getHostName() : addr.getHostAddress();
                            matcher=pat.matcher(name);
                            if(matcher.matches())
                                return addr;
                        }
                        break;
                }
            }
            catch (SocketException e) {
            }
        }
        return null;
    }


    /**
     * Returns the first address on the given interface on the current host, which satisfies scope
     *
     * @param intf the interface to be checked
     */
    public static InetAddress getAddress(NetworkInterface intf, AddressScope scope) {
        StackType ip_version=Util.getIpStackType();
        for(Enumeration addresses=intf.getInetAddresses(); addresses.hasMoreElements();) {
            InetAddress addr=(InetAddress)addresses.nextElement();
            boolean match=scope == null;
            if(scope != null) {
                switch(scope) {
                    case GLOBAL:
                        match=!addr.isLoopbackAddress() && !addr.isLinkLocalAddress() && !addr.isSiteLocalAddress();
                        break;
                    case SITE_LOCAL:
                        match=addr.isSiteLocalAddress();
                        break;
                    case LINK_LOCAL:
                        match=addr.isLinkLocalAddress();
                        break;
                    case LOOPBACK:
                        match=addr.isLoopbackAddress();
                        break;
                    case NON_LOOPBACK:
                        match=!addr.isLoopbackAddress();
                        break;
                    default:
                        throw new IllegalArgumentException("scope " + scope + " is unknown");
                }
            }

            if(match) {
                if((addr instanceof Inet4Address && ip_version == StackType.IPv4) ||
                  (addr instanceof Inet6Address && ip_version == StackType.IPv6))
                    return addr;
            }
        }
        return null ;
    }




    /**
     * A function to check if an interface supports an IP version (i.e has addresses
     * defined for that IP version).
     *
     * @param intf
     * @return
     */
    public static boolean interfaceHasIPAddresses(NetworkInterface intf, StackType ip_version) throws UnknownHostException {
        boolean supportsVersion = false ;
        if (intf != null) {
            // get all the InetAddresses defined on the interface
            Enumeration addresses = intf.getInetAddresses() ;
            while (addresses != null && addresses.hasMoreElements()) {
                // get the next InetAddress for the current interface
                InetAddress address = (InetAddress) addresses.nextElement() ;

                // check if we find an address of correct version
                if ((address instanceof Inet4Address && (ip_version == StackType.IPv4)) ||
                        (address instanceof Inet6Address && (ip_version == StackType.IPv6))) {
                    supportsVersion = true ;
                    break ;
                }
            }
        }
        else {
            throw new UnknownHostException("network interface " + intf + " not found") ;
        }
        return supportsVersion ;
    }

    public static StackType getIpStackType() {
       return ip_stack_type;
    }

    /** Returns true if the 2 addresses are of the same type (IPv4 or IPv6) */
    public static boolean sameAddresses(InetAddress one, InetAddress two) {
        return one == null
          || two == null
          || (one instanceof Inet6Address && two instanceof Inet6Address)
          || (one instanceof Inet4Address && two instanceof Inet4Address);
    }

    /**
     * Tries to determine the type of IP stack from the available interfaces and their addresses and from the
     * system properties (java.net.preferIPv4Stack and java.net.preferIPv6Addresses)
     * @return StackType.IPv4 for an IPv4 only stack, StackYTypeIPv6 for an IPv6 only stack, and StackType.Unknown
     * if the type cannot be detected
     */
    private static StackType _getIpStackType() {
        boolean isIPv4StackAvailable = isStackAvailable(true) ;
    	boolean isIPv6StackAvailable = isStackAvailable(false) ;

		// if only IPv4 stack available
		if (isIPv4StackAvailable && !isIPv6StackAvailable) {
			return StackType.IPv4;
		}
		// if only IPv6 stack available
		else if (isIPv6StackAvailable && !isIPv4StackAvailable) {
			return StackType.IPv6;
		}
		// if dual stack
		else if (isIPv4StackAvailable && isIPv6StackAvailable) {
			// get the System property which records user preference for a stack on a dual stack machine
            if(Boolean.getBoolean(Global.IPv4)) // has preference over java.net.preferIPv6Addresses
                return StackType.IPv4;
            if(Boolean.getBoolean(Global.IPv6))
                return StackType.IPv6;
            return StackType.IPv6;
		}
		return StackType.Unknown;
    }



	public static boolean isStackAvailable(boolean ipv4) {
        Collection<InetAddress> all_addrs=getAllAvailableAddresses();
        for(InetAddress addr: all_addrs)
            if(ipv4 && addr instanceof Inet4Address || (!ipv4 && addr instanceof Inet6Address))
                return true;
        return false;
    }


    public static List<NetworkInterface> getAllAvailableInterfaces() throws SocketException {
        List<NetworkInterface> retval=new ArrayList<NetworkInterface>(10);
        NetworkInterface intf;
        for(Enumeration en=NetworkInterface.getNetworkInterfaces(); en.hasMoreElements();) {
            intf=(NetworkInterface)en.nextElement();
            retval.add(intf);
        }
        return retval;
    }

    public static Collection<InetAddress> getAllAvailableAddresses() {
        Set<InetAddress> retval=new HashSet<InetAddress>();
        Enumeration en;

        try {
            en=NetworkInterface.getNetworkInterfaces();
            if(en == null)
                return retval;
            while(en.hasMoreElements()) {
                NetworkInterface intf=(NetworkInterface)en.nextElement();
                Enumeration<InetAddress> addrs=intf.getInetAddresses();
                while(addrs.hasMoreElements())
                    retval.add(addrs.nextElement());
            }
        }
        catch(SocketException e) {
            e.printStackTrace();
        }

        return retval;
    }

    public static void checkIfValidAddress(InetAddress bind_addr, String prot_name) throws Exception {
        if(bind_addr.isAnyLocalAddress() || bind_addr.isLoopbackAddress())
            return;
        Collection<InetAddress> addrs=getAllAvailableAddresses();
        for(InetAddress addr: addrs) {
            if(addr.equals(bind_addr))
                return;
        }
        throw new BindException("[" + prot_name + "] " + bind_addr + " is not a valid address on any local network interface");
    }



    /**
     * Returns a value associated wither with one or more system properties, or found in the props map
     * @param system_props
     * @param props List of properties read from the configuration file
     * @param prop_name The name of the property, will be removed from props if found
     * @param default_value Used to return a default value if the properties or system properties didn't have the value
     * @return The value, or null if not found
     */
    public static String getProperty(String[] system_props, Properties props, String prop_name, String default_value) {
        String retval=null;
        if(props != null && prop_name != null) {
            retval=props.getProperty(prop_name);
            props.remove(prop_name);
        }

        String tmp, prop;
        if(retval == null && system_props != null) {
            for(int i=0; i < system_props.length; i++) {
                prop=system_props[i];
                if(prop != null) {
                    try {
                        tmp=System.getProperty(prop);
                        if(tmp != null)
                            return tmp;
                    }
                    catch(SecurityException ex) {}
                }
            }
        }

        if(retval == null)
            return default_value;
        return retval;
    }


    public static boolean isCoordinator(JChannel ch) {
        return isCoordinator(ch.getView(), ch.getAddress());
    }


    public static boolean isCoordinator(View view, Address local_addr) {
        if(view == null || local_addr == null)
            return false;
        List<Address> mbrs=view.getMembers();
        return !(mbrs == null || mbrs.isEmpty()) && local_addr.equals(mbrs.iterator().next());
    }

    public static Address getCoordinator(View view) {
        if(view == null)
            return null;
        List<Address> mbrs=view.getMembers();
        return !mbrs.isEmpty()? mbrs.get(0) : null;
    }

    public static MBeanServer getMBeanServer() {
		ArrayList servers = MBeanServerFactory.findMBeanServer(null);
		if (servers != null && !servers.isEmpty()) {
			// return 'jboss' server if available
			for (int i = 0; i < servers.size(); i++) {
				MBeanServer srv = (MBeanServer) servers.get(i);
				if ("jboss".equalsIgnoreCase(srv.getDefaultDomain()))
					return srv;
			}

			// return first available server
			return (MBeanServer) servers.get(0);
		}
		else {
			//if it all fails, create a default
			return MBeanServerFactory.createMBeanServer();
		}
	}


    public static void registerChannel(JChannel channel, String name) {
        MBeanServer server=Util.getMBeanServer();
        if(server != null) {
            try {
                JmxConfigurator.registerChannel(channel,
                                                server,
                                                (name != null? name : "jgroups"),
                                                channel.getClusterName(),
                                                true);
            }
            catch(Exception e) {
                e.printStackTrace();
            }
        }
    }





    public static String generateList(Collection c, String separator) {
        if(c == null) return null;
        StringBuilder sb=new StringBuilder();
        boolean first=true;

        for(Iterator it=c.iterator(); it.hasNext();) {
            if(first) {
                first=false;
            }
            else {
                sb.append(separator);
            }
            sb.append(it.next());
        }
        return sb.toString();
    }


    /**
     * Go through the input string and replace any occurance of ${p} with the
     * props.getProperty(p) value. If there is no such property p defined, then
     * the ${p} reference will remain unchanged.
     *
     * If the property reference is of the form ${p:v} and there is no such
     * property p, then the default value v will be returned.
     *
     * If the property reference is of the form ${p1,p2} or ${p1,p2:v} then the
     * primary and the secondary properties will be tried in turn, before
     * returning either the unchanged input, or the default value.
     *
     * The property ${/} is replaced with System.getProperty("file.separator")
     * value and the property ${:} is replaced with
     * System.getProperty("path.separator").
     *
     * @param string -
     *                the string with possible ${} references
     * @param props -
     *                the source for ${x} property ref values, null means use
     *                System.getProperty()
     * @return the input string with all property references replaced if any. If
     *         there are no valid references the input string will be returned.
     * @throws {@link java.security.AccessControlException}
     *                 when not authorised to retrieved system properties
     */
    public static String replaceProperties(final String string, final Properties props) {
        /** File separator value */
        final String FILE_SEPARATOR=File.separator;

        /** Path separator value */
        final String PATH_SEPARATOR=File.pathSeparator;

        /** File separator alias */
        final String FILE_SEPARATOR_ALIAS="/";

        /** Path separator alias */
        final String PATH_SEPARATOR_ALIAS=":";

        // States used in property parsing
        final int NORMAL=0;
        final int SEEN_DOLLAR=1;
        final int IN_BRACKET=2;
        final char[] chars=string.toCharArray();
        StringBuilder buffer=new StringBuilder();
        boolean properties=false;
        int state=NORMAL;
        int start=0;
        for(int i=0;i < chars.length;++i) {
            char c=chars[i];

            // Dollar sign outside brackets
            if(c == '$' && state != IN_BRACKET)
                state=SEEN_DOLLAR;

            // Open bracket immediatley after dollar
            else if(c == '{' && state == SEEN_DOLLAR) {
                buffer.append(string.substring(start, i - 1));
                state=IN_BRACKET;
                start=i - 1;
            }

            // No open bracket after dollar
            else if(state == SEEN_DOLLAR)
                state=NORMAL;

            // Closed bracket after open bracket
            else if(c == '}' && state == IN_BRACKET) {
                // No content
                if(start + 2 == i) {
                    buffer.append("${}"); // REVIEW: Correct?
                }
                else // Collect the system property
                {
                    String value=null;

                    String key=string.substring(start + 2, i);

                    // check for alias
                    if(FILE_SEPARATOR_ALIAS.equals(key)) {
                        value=FILE_SEPARATOR;
                    }
                    else if(PATH_SEPARATOR_ALIAS.equals(key)) {
                        value=PATH_SEPARATOR;
                    }
                    else {
                        // check from the properties
                        if(props != null)
                            value=props.getProperty(key);
                        else
                            value=System.getProperty(key);

                        if(value == null) {
                            // Check for a default value ${key:default}
                            int colon=key.indexOf(':');
                            if(colon > 0) {
                                String realKey=key.substring(0, colon);
                                if(props != null)
                                    value=props.getProperty(realKey);
                                else
                                    value=System.getProperty(realKey);

                                if(value == null) {
                                    // Check for a composite key, "key1,key2"
                                    value=resolveCompositeKey(realKey, props);

                                    // Not a composite key either, use the specified default
                                    if(value == null)
                                        value=key.substring(colon + 1);
                                }
                            }
                            else {
                                // No default, check for a composite key, "key1,key2"
                                value=resolveCompositeKey(key, props);
                            }
                        }
                    }

                    if(value != null) {
                        properties=true;
                        buffer.append(value);
                    }
                }
                start=i + 1;
                state=NORMAL;
            }
        }

        // No properties
        if(properties == false)
            return string;

        // Collect the trailing characters
        if(start != chars.length)
            buffer.append(string.substring(start, chars.length));

        // Done
        return buffer.toString();
    }

    /**
     * Try to resolve a "key" from the provided properties by checking if it is
     * actually a "key1,key2", in which case try first "key1", then "key2". If
     * all fails, return null.
     *
     * It also accepts "key1," and ",key2".
     *
     * @param key
     *                the key to resolve
     * @param props
     *                the properties to use
     * @return the resolved key or null
     */
    private static String resolveCompositeKey(String key, Properties props) {
        String value=null;

        // Look for the comma
        int comma=key.indexOf(',');
        if(comma > -1) {
            // If we have a first part, try resolve it
            if(comma > 0) {
                // Check the first part
                String key1=key.substring(0, comma);
                if(props != null)
                    value=props.getProperty(key1);
                else
                    value=System.getProperty(key1);
            }
            // Check the second part, if there is one and first lookup failed
            if(value == null && comma < key.length() - 1) {
                String key2=key.substring(comma + 1);
                if(props != null)
                    value=props.getProperty(key2);
                else
                    value=System.getProperty(key2);
            }
        }
        // Return whatever we've found or null
        return value;
    }

//    /**
//     * Replaces variables with values from system properties. If a system property is not found, the property is
//     * removed from the output string
//     * @param input
//     * @return
//     */
//    public static String substituteVariables(String input) throws Exception {
//        Collection<Configurator.ProtocolConfiguration> configs=Configurator.parseConfigurations(input);
//        for(Configurator.ProtocolConfiguration config: configs) {
//            for(Iterator<Map.Entry<String,String>> it=config.getProperties().entrySet().iterator(); it.hasNext();) {
//                Map.Entry<String,String> entry=it.next();
//
//
//            }
//        }
//
//
//        return null;
//    }


    /**
     * Replaces variables of ${var:default} with System.getProperty(var, default). If no variables are found, returns
     * the same string, otherwise a copy of the string with variables substituted
     * @param val
     * @return A string with vars replaced, or the same string if no vars found
     */
    public static String substituteVariable(String val) {
        if(val == null)
            return val;
        String retval=val, prev;

        while(retval.contains("${")) { // handle multiple variables in val
            prev=retval;
            retval=_substituteVar(retval);
            if(retval.equals(prev))
                break;
        }
        return retval;
    }

    private static String _substituteVar(String val) {
        int start_index, end_index;
        start_index=val.indexOf("${");
        if(start_index == -1)
            return val;
        end_index=val.indexOf("}", start_index+2);
        if(end_index == -1)
            throw new IllegalArgumentException("missing \"}\" in " + val);

        String tmp=getProperty(val.substring(start_index +2, end_index));
        if(tmp == null)
            return val;
        StringBuilder sb=new StringBuilder();
        sb.append(val.substring(0, start_index));
        sb.append(tmp);
        sb.append(val.substring(end_index+1));
        return sb.toString();
    }

    public static String getProperty(String s) {
        String var, default_val, retval=null;
        int index=s.indexOf(":");
        if(index >= 0) {
            var=s.substring(0, index);
            default_val=s.substring(index+1);
            if(default_val != null && !default_val.isEmpty())
                default_val=default_val.trim();
            // retval=System.getProperty(var, default_val);
            retval=_getProperty(var, default_val);
        }
        else {
            var=s;
            // retval=System.getProperty(var);
            retval=_getProperty(var, null);
        }
        return retval;
    }

    /**
     * Parses a var which might be comma delimited, e.g. bla,foo:1000: if 'bla' is set, return its value. Else,
     * if 'foo' is set, return its value, else return "1000"
     * @param var
     * @param default_value
     * @return
     */
    private static String _getProperty(String var, String default_value) {
        if(var == null)
            return null;
        List<String> list=parseCommaDelimitedStrings(var);
        if(list == null || list.isEmpty()) {
            list=new ArrayList<String>(1);
            list.add(var);
        }
        String retval=null;
        for(String prop: list) {
            try {
                retval=System.getProperty(prop);
                if(retval != null)
                    return retval;
            }
            catch(Throwable e) {
            }
        }
        return default_value;
    }


     /**
     * Used to convert a byte array in to a java.lang.String object
     * @param bytes the bytes to be converted
     * @return the String representation
     */
    private static String getString(byte[] bytes) {
         StringBuilder sb=new StringBuilder();
         for (int i = 0; i < bytes.length; i++) {
            byte b = bytes[i];
            sb.append(0x00FF & b);
            if (i + 1 < bytes.length) {
                sb.append("-");
            }
        }
        return sb.toString();
    }


    /**
     * Converts a java.lang.String in to a MD5 hashed String
     * @param source the source String
     * @return the MD5 hashed version of the string
     */
    public static String md5(String source) {
        try {
            MessageDigest md = MessageDigest.getInstance("MD5");
            byte[] bytes = md.digest(source.getBytes());
            return getString(bytes);
        } catch (Exception e) {
            return null;
        }
    }
    /**
     * Converts a java.lang.String in to a SHA hashed String
     * @param source the source String
     * @return the MD5 hashed version of the string
     */
    public static String sha(String source) {
        try {
            MessageDigest md = MessageDigest.getInstance("SHA");
            byte[] bytes = md.digest(source.getBytes());
            return getString(bytes);
        } catch (Exception e) {
            e.printStackTrace();
            return null;
        }
    }

    /**
     * Converts a method name to an attribute name, e.g. getFooBar() --> foo_bar, isFlag --> flag.
     * @param methodName
     * @return
     */
    public static String methodNameToAttributeName(final String methodName) {
        String name=methodName;
        if((methodName.startsWith("get") || methodName.startsWith("set")) && methodName.length() > 3)
            name=methodName.substring(3);
        else if(methodName.startsWith("is") && methodName.length() > 2)
            name=methodName.substring(2);

        // Pattern p=Pattern.compile("[A-Z]+");
        Matcher m=METHOD_NAME_TO_ATTR_NAME_PATTERN.matcher(name);
        StringBuffer sb=new StringBuffer();
        while(m.find()) {
            int start=m.start(), end=m.end();
            String str=name.substring(start, end).toLowerCase();
            if(str.length() > 1) {
                String tmp1=str.substring(0, str.length() -1);
                String tmp2=str.substring(str.length() -1);
                str=tmp1 + "_" + tmp2;
            }
            if(start == 0) {
                m.appendReplacement(sb, str);
            }
            else
                m.appendReplacement(sb, "_" + str);
        }
        m.appendTail(sb);
        return sb.length() > 0? sb.toString() : methodName;
    }

    /**
     * Converts a method name to a Java attribute name, e.g. getFooBar() --> fooBar, isFlag --> flag.
     * @param methodName
     * @return
     */
    public static String methodNameToJavaAttributeName(final String methodName) {
          String name=methodName;
          if((methodName.startsWith("get") || methodName.startsWith("set")) && methodName.length() > 3)
              name=methodName.substring(3);
          else if(methodName.startsWith("is") && methodName.length() > 2)
              name=methodName.substring(2);

        if(Character.isUpperCase(name.charAt(0)))
            return name.substring(0, 1).toLowerCase() + name.substring(1);
        return name;
      }


    public static String attributeNameToMethodName(String attr_name) {
        if(attr_name.contains("_")) {
            // Pattern p=Pattern.compile("_.");
            Matcher m=ATTR_NAME_TO_METHOD_NAME_PATTERN.matcher(attr_name);
            StringBuffer sb=new StringBuffer();
            while(m.find()) {
                m.appendReplacement(sb, attr_name.substring(m.end() - 1, m.end()).toUpperCase());
            }
            m.appendTail(sb);
            char first=sb.charAt(0);
            if(Character.isLowerCase(first)) {
                sb.setCharAt(0, Character.toUpperCase(first));
            }
            return sb.toString();
        }
        else {
            if(Character.isLowerCase(attr_name.charAt(0))) {
                return attr_name.substring(0, 1).toUpperCase() + attr_name.substring(1);
            }
            else {
                return attr_name;
            }
        }
    }

    public static String attributeNameToJavaMethodName(String attr_name) {
        String retval=attributeNameToMethodName(attr_name);
        if(Character.isUpperCase(retval.charAt(0)))
            return retval.substring(0, 1).toLowerCase() + retval.substring(1);
        return retval;
    }



    /**
     * Runs a task on a separate thread
     * @param task
     * @param factory
     * @param group
     * @param thread_name
     */
    public static void runAsync(Runnable task, ThreadFactory factory, String thread_name) {
        Thread thread=factory.newThread(task, thread_name);
        thread.start();
    }




}




