Monitoring and Management Interface for the Java Platform

com.sun.management
Class GcInfo

java.lang.Object
  extended by com.sun.management.GcInfo
All Implemented Interfaces:
CompositeData, CompositeDataView

public class GcInfo
extends Object
implements CompositeData, CompositeDataView

Garbage collection information. It contains the following information for one garbage collection as well as GC-specific attributes:

GcInfo is a CompositeData The GC-specific attributes can be obtained via the CompositeData interface. This is a historical relic, and other classes should not copy this pattern. Use CompositeDataView instead.

MXBean Mapping

GcInfo is mapped to a CompositeData with attributes as specified in the from method.

Since:
1.5

Method Summary
 boolean containsKey(String key)
          Returns true if and only if this CompositeData instance contains an item whose name is key.
 boolean containsValue(Object value)
          Returns true if and only if this CompositeData instance contains an item whose value is value.
 boolean equals(Object obj)
          Indicates whether some other object is "equal to" this one.
static GcInfo from(CompositeData cd)
          Returns a GcInfo object represented by the given CompositeData.
 Object get(String key)
          Returns the value of the item whose name is key.
 Object[] getAll(String[] keys)
          Returns an array of the values of the items whose names are specified by keys, in the same order as keys.
 CompositeType getCompositeType()
          Returns the composite type of this composite data instance.
 long getDuration()
          Returns the elapsed time of this GC in milliseconds.
 long getEndTime()
          Returns the end time of this GC in milliseconds since the Java virtual machine was started.
 long getId()
          Returns the identifier of this garbage collection which is the number of collections that this collector has done.
 Map<String,MemoryUsage> getMemoryUsageAfterGc()
          Returns the memory usage of all memory pools at the end of this GC.
 Map<String,MemoryUsage> getMemoryUsageBeforeGc()
          Returns the memory usage of all memory pools at the beginning of this GC.
 long getStartTime()
          Returns the start time of this GC in milliseconds since the Java virtual machine was started.
 int hashCode()
          Returns a hash code value for the object.
 CompositeData toCompositeData(CompositeType ct)
          Return the CompositeData representation of this GcInfo, including any GC-specific attributes.
 String toString()
          Returns a string representation of the object.
 Collection values()
          Returns an unmodifiable Collection view of the item values contained in this CompositeData instance.
 
Methods inherited from class java.lang.Object
clone, finalize, getClass, notify, notifyAll, wait, wait, wait
 

Method Detail

getId

public long getId()
Returns the identifier of this garbage collection which is the number of collections that this collector has done.

Returns:
the identifier of this garbage collection which is the number of collections that this collector has done.

getStartTime

public long getStartTime()
Returns the start time of this GC in milliseconds since the Java virtual machine was started.

Returns:
the start time of this GC.

getEndTime

public long getEndTime()
Returns the end time of this GC in milliseconds since the Java virtual machine was started.

Returns:
the end time of this GC.

getDuration

public long getDuration()
Returns the elapsed time of this GC in milliseconds.

Returns:
the elapsed time of this GC in milliseconds.

getMemoryUsageBeforeGc

public Map<String,MemoryUsage> getMemoryUsageBeforeGc()
Returns the memory usage of all memory pools at the beginning of this GC. This method returns a Map of the name of a memory pool to the memory usage of the corresponding memory pool before GC starts.

Returns:
a Map of memory pool names to the memory usage of a memory pool before GC starts.

getMemoryUsageAfterGc

public Map<String,MemoryUsage> getMemoryUsageAfterGc()
Returns the memory usage of all memory pools at the end of this GC. This method returns a Map of the name of a memory pool to the memory usage of the corresponding memory pool when GC finishes.

Returns:
a Map of memory pool names to the memory usage of a memory pool when GC finishes.

from

public static GcInfo from(CompositeData cd)
Returns a GcInfo object represented by the given CompositeData. The given CompositeData must contain all the following attributes:

Attribute Name Type
index java.lang.Long
startTime java.lang.Long
endTime java.lang.Long
memoryUsageBeforeGc javax.management.openmbean.TabularData
memoryUsageAfterGc javax.management.openmbean.TabularData

Returns:
a GcInfo object represented by cd if cd is not null; null otherwise.
Throws:
IllegalArgumentException - if cd does not represent a GcInfo object with the attributes described above.

containsKey

public boolean containsKey(String key)
Description copied from interface: javax.management.openmbean.CompositeData
Returns true if and only if this CompositeData instance contains an item whose name is key. If key is a null or empty String, this method simply returns false.

Specified by:
containsKey in interface CompositeData
Parameters:
key - the key to be tested.
Returns:
true if this CompositeData contains the key.

containsValue

public boolean containsValue(Object value)
Description copied from interface: javax.management.openmbean.CompositeData
Returns true if and only if this CompositeData instance contains an item whose value is value.

Specified by:
containsValue in interface CompositeData
Parameters:
value - the value to be tested.
Returns:
true if this CompositeData contains the value.

equals

public boolean equals(Object obj)
Description copied from class: java.lang.Object
Indicates whether some other object is "equal to" this one.

The equals method implements an equivalence relation on non-null object references:

The equals method for class Object implements the most discriminating possible equivalence relation on objects; that is, for any non-null reference values x and y, this method returns true if and only if x and y refer to the same object (x == y has the value true).

Note that it is generally necessary to override the hashCode method whenever this method is overridden, so as to maintain the general contract for the hashCode method, which states that equal objects must have equal hash codes.

Specified by:
equals in interface CompositeData
Overrides:
equals in class Object
Parameters:
obj - the reference object with which to compare.
Returns:
true if this object is the same as the obj argument; false otherwise.
See Also:
Object.hashCode(), Hashtable

get

public Object get(String key)
Description copied from interface: javax.management.openmbean.CompositeData
Returns the value of the item whose name is key.

Specified by:
get in interface CompositeData
Parameters:
key - the name of the item.
Returns:
the value associated with this key.

getAll

public Object[] getAll(String[] keys)
Description copied from interface: javax.management.openmbean.CompositeData
Returns an array of the values of the items whose names are specified by keys, in the same order as keys.

Specified by:
getAll in interface CompositeData
Parameters:
keys - the names of the items.
Returns:
the values corresponding to the keys.

getCompositeType

public CompositeType getCompositeType()
Description copied from interface: javax.management.openmbean.CompositeData
Returns the composite type of this composite data instance.

Specified by:
getCompositeType in interface CompositeData
Returns:
the type of this CompositeData.

hashCode

public int hashCode()
Description copied from class: java.lang.Object
Returns a hash code value for the object. This method is supported for the benefit of hashtables such as those provided by java.util.Hashtable.

The general contract of hashCode is:

As much as is reasonably practical, the hashCode method defined by class Object does return distinct integers for distinct objects. (This is typically implemented by converting the internal address of the object into an integer, but this implementation technique is not required by the JavaTM programming language.)

Specified by:
hashCode in interface CompositeData
Overrides:
hashCode in class Object
Returns:
a hash code value for this object.
See Also:
Object.equals(java.lang.Object), Hashtable

toString

public String toString()
Description copied from class: java.lang.Object
Returns a string representation of the object. In general, the toString method returns a string that "textually represents" this object. The result should be a concise but informative representation that is easy for a person to read. It is recommended that all subclasses override this method.

The toString method for class Object returns a string consisting of the name of the class of which the object is an instance, the at-sign character `@', and the unsigned hexadecimal representation of the hash code of the object. In other words, this method returns a string equal to the value of:

 getClass().getName() + '@' + Integer.toHexString(hashCode())
 

Specified by:
toString in interface CompositeData
Overrides:
toString in class Object
Returns:
a string representation of the object.

values

public Collection values()
Description copied from interface: javax.management.openmbean.CompositeData
Returns an unmodifiable Collection view of the item values contained in this CompositeData instance. The returned collection's iterator will return the values in the ascending lexicographic order of the corresponding item names.

Specified by:
values in interface CompositeData
Returns:
the values.

toCompositeData

public CompositeData toCompositeData(CompositeType ct)

Return the CompositeData representation of this GcInfo, including any GC-specific attributes. The returned value will have at least all the attributes described in the from method, plus optionally other attributes.

Specified by:
toCompositeData in interface CompositeDataView
Parameters:
ct - the CompositeType that the caller expects. This parameter is ignored and can be null.
Returns:
the CompositeData representation.

Monitoring and Management Interface for the Java Platform

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