001/* ========================================================================
002 * JCommon : a free general purpose class library for the Java(tm) platform
003 * ========================================================================
004 *
005 * (C) Copyright 2000-2005, by Object Refinery Limited and Contributors.
006 * 
007 * Project Info:  http://www.jfree.org/jcommon/index.html
008 *
009 * This library is free software; you can redistribute it and/or modify it 
010 * under the terms of the GNU Lesser General Public License as published by 
011 * the Free Software Foundation; either version 2.1 of the License, or 
012 * (at your option) any later version.
013 *
014 * This library is distributed in the hope that it will be useful, but 
015 * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY 
016 * or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public 
017 * License for more details.
018 *
019 * You should have received a copy of the GNU Lesser General Public
020 * License along with this library; if not, write to the Free Software
021 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, 
022 * USA.  
023 *
024 * [Java is a trademark or registered trademark of Sun Microsystems, Inc. 
025 * in the United States and other countries.]
026 * 
027 * -------------------------
028 * DefaultConfiguration.java
029 * -------------------------
030 * (C)opyright 2003, 2004, by Thomas Morgner and Contributors.
031 *
032 * Original Author:  Thomas Morgner;
033 * Contributor(s):   David Gilbert (for Object Refinery Limited);
034 *
035 * $Id: DefaultConfiguration.java,v 1.5 2006/12/03 15:33:33 taqua Exp $
036 *
037 * Changes
038 * -------
039 * 04.06.2003 : Initial version (TM);
040 *
041 */
042
043package org.jfree.util;
044
045import java.util.Collections;
046import java.util.Enumeration;
047import java.util.Iterator;
048import java.util.Properties;
049import java.util.TreeSet;
050
051import org.jfree.base.config.ModifiableConfiguration;
052
053/**
054 * Default configuration.
055 *
056 * @author Thomas Morgner.
057 */
058public class DefaultConfiguration extends Properties
059    implements ModifiableConfiguration
060{
061
062  /**
063   * Creates an empty property list with no default values.
064   */
065  public DefaultConfiguration()
066  {
067    super();
068  }
069
070  /**
071   * Returns the configuration property with the specified key.
072   *
073   * @param key the property key.
074   * @return the property value.
075   */
076  public String getConfigProperty(final String key)
077  {
078    return getProperty(key);
079  }
080
081  /**
082   * Returns the configuration property with the specified key (or the
083   * specified default value if there is no such property).
084   * <p/>
085   * If the property is not defined in this configuration, the code will
086   * lookup the property in the parent configuration.
087   *
088   * @param key          the property key.
089   * @param defaultValue the default value.
090   * @return the property value.
091   */
092  public String getConfigProperty(final String key, final String defaultValue)
093  {
094    return getProperty(key, defaultValue);
095  }
096
097  /**
098   * Searches all property keys that start with a given prefix.
099   *
100   * @param prefix the prefix that all selected property keys should share
101   * @return the properties as iterator.
102   */
103  public Iterator findPropertyKeys(final String prefix)
104  {
105    final TreeSet collector = new TreeSet();
106    final Enumeration enum1 = keys();
107    while (enum1.hasMoreElements())
108    {
109      final String key = (String) enum1.nextElement();
110      if (key.startsWith(prefix))
111      {
112        if (collector.contains(key) == false)
113        {
114          collector.add(key);
115        }
116      }
117    }
118    return Collections.unmodifiableSet(collector).iterator();
119  }
120
121  public Enumeration getConfigProperties()
122  {
123    return keys();
124  }
125
126  /**
127   * Sets the value of a configuration property.
128   *
129   * @param key   the property key.
130   * @param value the property value.
131   */
132  public void setConfigProperty(final String key, final String value)
133  {
134    if (value == null)
135    {
136      remove(key);
137    }
138    else
139    {
140      setProperty(key, value);
141    }
142  }
143}