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 * Copyright (c) 2003, 2017, Oracle and/or its affiliates. All rights reserved.

 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.

 *

 * This code is free software; you can redistribute it and/or modify it

 * under the terms of the GNU General Public License version 2 only, as

 * published by the Free Software Foundation.  Oracle designates this

 * particular file as subject to the "Classpath" exception as provided

 * by Oracle in the LICENSE file that accompanied this code.

 *

 * This code is distributed in the hope that it will be useful, but WITHOUT

 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or

 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License

 * version 2 for more details (a copy is included in the LICENSE file that

 * accompanied this code).

 *

 * You should have received a copy of the GNU General Public License version

 * 2 along with this work; if not, write to the Free Software Foundation,

 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.

 *

 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA

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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:

 * <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.

 *

 * <h3>MXBean Mapping</h3>

 * {@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.

     *

     * @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.

     *

     * @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.

     *

     * @return the end time of this GC.

     */

    public long getEndTime() {

        return endTime;

    }

    /**

     * 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 {@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 {@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 {@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 {@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;

    }

}