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package com.sun.management;

import java.lang.management.MemoryUsage;
import javax.management.openmbean.CompositeData;
import javax.management.openmbean.CompositeDataView;
import javax.management.openmbean.CompositeType;
import java.util.Collection;
import java.util.Collections;
import java.util.HashMap;
import java.util.Map;
import com.sun.management.internal.GcInfoCompositeData;
import com.sun.management.internal.GcInfoBuilder;

Garbage collection information. It contains the following information for one garbage collection as well as GC-specific attributes:
  • Start time
  • End time
  • Duration
  • Memory usage before the collection starts
  • Memory usage after the collection ends

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.
Author: Mandy Chung
Since: 1.5
/** * Garbage collection information. It contains the following * information for one garbage collection as well as GC-specific * attributes: * <blockquote> * <ul> * <li>Start time</li> * <li>End time</li> * <li>Duration</li> * <li>Memory usage before the collection starts</li> * <li>Memory usage after the collection ends</li> * </ul> * </blockquote> * * <p> * {@code GcInfo} is a {@link CompositeData 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 {@link CompositeDataView} instead. * * <h2>MXBean Mapping</h2> * {@code GcInfo} is mapped to a {@link CompositeData CompositeData} * with attributes as specified in the {@link #from from} method. * * @author Mandy Chung * @since 1.5 */
public class GcInfo implements CompositeData, CompositeDataView { private final long index; private final long startTime; private final long endTime; private final Map<String, MemoryUsage> usageBeforeGc; private final Map<String, MemoryUsage> usageAfterGc; private final Object[] extAttributes; private final CompositeData cdata; private final GcInfoBuilder builder; private GcInfo(GcInfoBuilder builder, long index, long startTime, long endTime, MemoryUsage[] muBeforeGc, MemoryUsage[] muAfterGc, Object[] extAttributes) { this.builder = builder; this.index = index; this.startTime = startTime; this.endTime = endTime; String[] poolNames = builder.getPoolNames(); this.usageBeforeGc = new HashMap<String, MemoryUsage>(poolNames.length); this.usageAfterGc = new HashMap<String, MemoryUsage>(poolNames.length); for (int i = 0; i < poolNames.length; i++) { this.usageBeforeGc.put(poolNames[i], muBeforeGc[i]); this.usageAfterGc.put(poolNames[i], muAfterGc[i]); } this.extAttributes = extAttributes; this.cdata = new GcInfoCompositeData(this, builder, extAttributes); } private GcInfo(CompositeData cd) { GcInfoCompositeData.validateCompositeData(cd); this.index = GcInfoCompositeData.getId(cd); this.startTime = GcInfoCompositeData.getStartTime(cd); this.endTime = GcInfoCompositeData.getEndTime(cd); this.usageBeforeGc = GcInfoCompositeData.getMemoryUsageBeforeGc(cd); this.usageAfterGc = GcInfoCompositeData.getMemoryUsageAfterGc(cd); this.extAttributes = null; this.builder = null; this.cdata = cd; }
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.
/** * Returns the identifier of this garbage collection which is * the number of collections that this collector has done. * * @return the identifier of this garbage collection which is * the number of collections that this collector has done. */
public long getId() { return index; }
Returns the start time of this GC in milliseconds since the Java virtual machine was started.
Returns:the start time of this GC.
/** * Returns the start time of this GC in milliseconds * since the Java virtual machine was started. * * @return the start time of this GC. */
public long getStartTime() { return startTime; }
Returns the end time of this GC in milliseconds since the Java virtual machine was started.
Returns:the end time of this GC.
/** * Returns the end time of this GC in milliseconds * since the Java virtual machine was started. * * @return the end time of this GC. */
public long getEndTime() { return endTime; }
Returns the elapsed time of this GC in milliseconds.
Returns:the elapsed time of this GC in milliseconds.
/** * Returns the elapsed time of this GC in milliseconds. * * @return the elapsed time of this GC in milliseconds. */
public long getDuration() { return endTime - startTime; }
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.
/** * Returns the memory usage of all memory pools * at the beginning of this GC. * This method returns * a {@code Map} of the name of a memory pool * to the memory usage of the corresponding * memory pool before GC starts. * * @return a {@code Map} of memory pool names to the memory * usage of a memory pool before GC starts. */
public Map<String, MemoryUsage> getMemoryUsageBeforeGc() { return Collections.unmodifiableMap(usageBeforeGc); }
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.
/** * Returns the memory usage of all memory pools * at the end of this GC. * This method returns * a {@code Map} of the name of a memory pool * to the memory usage of the corresponding * memory pool when GC finishes. * * @return a {@code Map} of memory pool names to the memory * usage of a memory pool when GC finishes. */
public Map<String, MemoryUsage> getMemoryUsageAfterGc() { return Collections.unmodifiableMap(usageAfterGc); }
Returns a GcInfo object represented by the given CompositeData. The given CompositeData must contain all the following attributes:
description
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
Throws:
Returns:a GcInfo object represented by cd if cd is not null; null otherwise.
/** * Returns a {@code GcInfo} object represented by the * given {@code CompositeData}. The given * {@code CompositeData} must contain * all the following attributes: * * <blockquote> * <table class="striped"><caption style="display:none">description</caption> * <thead> * <tr> * <th scope="col" style="text-align:left">Attribute Name</th> * <th scope="col" style="text-align:left">Type</th> * </tr> * </thead> * <tbody> * <tr> * <th scope="row">index</th> * <td>{@code java.lang.Long}</td> * </tr> * <tr> * <th scope="row">startTime</th> * <td>{@code java.lang.Long}</td> * </tr> * <tr> * <th scope="row">endTime</th> * <td>{@code java.lang.Long}</td> * </tr> * <tr> * <th scope="row">memoryUsageBeforeGc</th> * <td>{@code javax.management.openmbean.TabularData}</td> * </tr> * <tr> * <th scope="row">memoryUsageAfterGc</th> * <td>{@code javax.management.openmbean.TabularData}</td> * </tr> * </tbody> * </table> * </blockquote> * * @throws IllegalArgumentException if {@code cd} does not * represent a {@code GcInfo} object with the attributes * described above. * * @return a {@code GcInfo} object represented by {@code cd} * if {@code cd} is not {@code null}; {@code null} otherwise. */
public static GcInfo from(CompositeData cd) { if (cd == null) { return null; } if (cd instanceof GcInfoCompositeData) { return ((GcInfoCompositeData) cd).getGcInfo(); } else { return new GcInfo(cd); } } // Implementation of the CompositeData interface public boolean containsKey(String key) { return cdata.containsKey(key); } public boolean containsValue(Object value) { return cdata.containsValue(value); } public boolean equals(Object obj) { return cdata.equals(obj); } public Object get(String key) { return cdata.get(key); } public Object[] getAll(String[] keys) { return cdata.getAll(keys); } public CompositeType getCompositeType() { return cdata.getCompositeType(); } public int hashCode() { return cdata.hashCode(); } public String toString() { return cdata.toString(); } public Collection<?> values() { return cdata.values(); }
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.
Params:
  • ct – the CompositeType that the caller expects. This parameter is ignored and can be null.
Returns:the CompositeData representation.
/** * Return the {@code CompositeData} representation of this * {@code GcInfo}, including any GC-specific attributes. The * returned value will have at least all the attributes described * in the {@link #from(CompositeData) from} method, plus optionally * other attributes. * * @param ct the {@code CompositeType} that the caller expects. * This parameter is ignored and can be null. * * @return the {@code CompositeData} representation. */
public CompositeData toCompositeData(CompositeType ct) { return cdata; } }