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 * Copyright (c) 2003, 2008, 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 java.lang.management;

import javax.management.openmbean.CompositeData;

import sun.management.ManagementFactoryHelper;

import sun.management.ThreadInfoCompositeData;

import static java.lang.Thread.State.*;

/**

 * Thread information. <tt>ThreadInfo</tt> contains the information

 * about a thread including:

 * <h4>General thread information</h4>

 * <ul>

 *   <li>Thread ID.</li>

 *   <li>Name of the thread.</li>

 * </ul>

 *

 * <h4>Execution information</h4>

 * <ul>

 *   <li>Thread state.</li>

 *   <li>The object upon which the thread is blocked due to:

 *       <ul>

 *       <li>waiting to enter a synchronization block/method, or</li>

 *       <li>waiting to be notified in a {@link Object#wait Object.wait} method,

 *           or</li>

 *       <li>parking due to a {@link java.util.concurrent.locks.LockSupport#park

 *           LockSupport.park} call.</li>

 *       </ul>

 *   </li>

 *   <li>The ID of the thread that owns the object

 *       that the thread is blocked.</li>

 *   <li>Stack trace of the thread.</li>

 *   <li>List of object monitors locked by the thread.</li>

 *   <li>List of <a href="LockInfo.html#OwnableSynchronizer">

 *       ownable synchronizers</a> locked by the thread.</li>

 * </ul>

 *

 * <h4><a name="SyncStats">Synchronization Statistics</a></h4>

 * <ul>

 *   <li>The number of times that the thread has blocked for

 *       synchronization or waited for notification.</li>

 *   <li>The accumulated elapsed time that the thread has blocked

 *       for synchronization or waited for notification

 *       since {@link ThreadMXBean#setThreadContentionMonitoringEnabled

 *       thread contention monitoring}

 *       was enabled. Some Java virtual machine implementation

 *       may not support this.  The

 *       {@link ThreadMXBean#isThreadContentionMonitoringSupported()}

 *       method can be used to determine if a Java virtual machine

 *       supports this.</li>

 * </ul>

 *

 * <p>This thread information class is designed for use in monitoring of

 * the system, not for synchronization control.

 *

 * <h4>MXBean Mapping</h4>

 * <tt>ThreadInfo</tt> is mapped to a {@link CompositeData CompositeData}

 * with attributes as specified in

 * the {@link #from from} method.

 *

 * @see ThreadMXBean#getThreadInfo

 * @see ThreadMXBean#dumpAllThreads

 *

 * @author  Mandy Chung

 * @since   1.5

 */

public class ThreadInfo {

    private String       threadName;

    private long         threadId;

    private long         blockedTime;

    private long         blockedCount;

    private long         waitedTime;

    private long         waitedCount;

    private LockInfo     lock;

    private String       lockName;

    private long         lockOwnerId;

    private String       lockOwnerName;

    private boolean      inNative;

    private boolean      suspended;

    private Thread.State threadState;

    private StackTraceElement[] stackTrace;

    private MonitorInfo[]       lockedMonitors;

    private LockInfo[]          lockedSynchronizers;

    private static MonitorInfo[] EMPTY_MONITORS = new MonitorInfo[0];

    private static LockInfo[] EMPTY_SYNCS = new LockInfo[0];

    /**

     * Constructor of ThreadInfo created by the JVM

     *

     * @param t             Thread

     * @param state         Thread state

     * @param lockObj       Object on which the thread is blocked

     * @param lockOwner     the thread holding the lock

     * @param blockedCount  Number of times blocked to enter a lock

     * @param blockedTime   Approx time blocked to enter a lock

     * @param waitedCount   Number of times waited on a lock

     * @param waitedTime    Approx time waited on a lock

     * @param stackTrace    Thread stack trace

     */

    private ThreadInfo(Thread t, int state, Object lockObj, Thread lockOwner,

                       long blockedCount, long blockedTime,

                       long waitedCount, long waitedTime,

                       StackTraceElement[] stackTrace) {

        initialize(t, state, lockObj, lockOwner,

                   blockedCount, blockedTime,

                   waitedCount, waitedTime, stackTrace,

                   EMPTY_MONITORS, EMPTY_SYNCS);

    }

    /**

     * Constructor of ThreadInfo created by the JVM

     * for {@link ThreadMXBean#getThreadInfo(long[],boolean,boolean)}

     * and {@link ThreadMXBean#dumpAllThreads}

     *

     * @param t             Thread

     * @param state         Thread state

     * @param lockObj       Object on which the thread is blocked

     * @param lockOwner     the thread holding the lock

     * @param blockedCount  Number of times blocked to enter a lock

     * @param blockedTime   Approx time blocked to enter a lock

     * @param waitedCount   Number of times waited on a lock

     * @param waitedTime    Approx time waited on a lock

     * @param stackTrace    Thread stack trace

     */

    private ThreadInfo(Thread t, int state, Object lockObj, Thread lockOwner,

                       long blockedCount, long blockedTime,

                       long waitedCount, long waitedTime,

                       StackTraceElement[] stackTrace,

                       Object[] monitors,

                       int[] stackDepths,

                       Object[] synchronizers) {

        int numMonitors = (monitors == null ? 0 : monitors.length);

        MonitorInfo[] lockedMonitors;

        if (numMonitors == 0) {

            lockedMonitors = EMPTY_MONITORS;

        } else {

            lockedMonitors = new MonitorInfo[numMonitors];

            for (int i = 0; i < numMonitors; i++) {

                Object lock = monitors[i];

                String className = lock.getClass().getName();

                int identityHashCode = System.identityHashCode(lock);

                int depth = stackDepths[i];

                StackTraceElement ste = (depth >= 0 ? stackTrace[depth]

                                                    : null);

                lockedMonitors[i] = new MonitorInfo(className,

                                                    identityHashCode,

                                                    depth,

                                                    ste);

            }

        }

        int numSyncs = (synchronizers == null ? 0 : synchronizers.length);

        LockInfo[] lockedSynchronizers;

        if (numSyncs == 0) {

            lockedSynchronizers = EMPTY_SYNCS;

        } else {

            lockedSynchronizers = new LockInfo[numSyncs];

            for (int i = 0; i < numSyncs; i++) {

                Object lock = synchronizers[i];

                String className = lock.getClass().getName();

                int identityHashCode = System.identityHashCode(lock);

                lockedSynchronizers[i] = new LockInfo(className,

                                                      identityHashCode);

            }

        }

        initialize(t, state, lockObj, lockOwner,

                   blockedCount, blockedTime,

                   waitedCount, waitedTime, stackTrace,

                   lockedMonitors, lockedSynchronizers);

    }

    /**

     * Initialize ThreadInfo object

     *

     * @param t             Thread

     * @param state         Thread state

     * @param lockObj       Object on which the thread is blocked

     * @param lockOwner     the thread holding the lock

     * @param blockedCount  Number of times blocked to enter a lock

     * @param blockedTime   Approx time blocked to enter a lock

     * @param waitedCount   Number of times waited on a lock

     * @param waitedTime    Approx time waited on a lock

     * @param stackTrace    Thread stack trace

     * @param lockedMonitors List of locked monitors

     * @param lockedSynchronizers List of locked synchronizers

     */

    private void initialize(Thread t, int state, Object lockObj, Thread lockOwner,

                            long blockedCount, long blockedTime,

                            long waitedCount, long waitedTime,

                            StackTraceElement[] stackTrace,

                            MonitorInfo[] lockedMonitors,

                            LockInfo[] lockedSynchronizers) {

        this.threadId = t.getId();

        this.threadName = t.getName();

        this.threadState = ManagementFactoryHelper.toThreadState(state);

        this.suspended = ManagementFactoryHelper.isThreadSuspended(state);

        this.inNative = ManagementFactoryHelper.isThreadRunningNative(state);

        this.blockedCount = blockedCount;

        this.blockedTime = blockedTime;

        this.waitedCount = waitedCount;

        this.waitedTime = waitedTime;

        if (lockObj == null) {

            this.lock = null;

            this.lockName = null;

        } else {

            this.lock = new LockInfo(lockObj);

            this.lockName =

                lock.getClassName() + '@' +

                    Integer.toHexString(lock.getIdentityHashCode());

        }

        if (lockOwner == null) {

            this.lockOwnerId = -1;

            this.lockOwnerName = null;

        } else {

            this.lockOwnerId = lockOwner.getId();

            this.lockOwnerName = lockOwner.getName();

        }

        if (stackTrace == null) {

            this.stackTrace = NO_STACK_TRACE;

        } else {

            this.stackTrace = stackTrace;

        }

        this.lockedMonitors = lockedMonitors;

        this.lockedSynchronizers = lockedSynchronizers;

    }

    /*

     * Constructs a <tt>ThreadInfo</tt> object from a

     * {@link CompositeData CompositeData}.

     */

    private ThreadInfo(CompositeData cd) {

        ThreadInfoCompositeData ticd = ThreadInfoCompositeData.getInstance(cd);

        threadId = ticd.threadId();

        threadName = ticd.threadName();

        blockedTime = ticd.blockedTime();

        blockedCount = ticd.blockedCount();

        waitedTime = ticd.waitedTime();

        waitedCount = ticd.waitedCount();

        lockName = ticd.lockName();

        lockOwnerId = ticd.lockOwnerId();

        lockOwnerName = ticd.lockOwnerName();

        threadState = ticd.threadState();

        suspended = ticd.suspended();

        inNative = ticd.inNative();

        stackTrace = ticd.stackTrace();

        // 6.0 attributes

        if (ticd.isCurrentVersion()) {

            lock = ticd.lockInfo();

            lockedMonitors = ticd.lockedMonitors();

            lockedSynchronizers = ticd.lockedSynchronizers();

        } else {

            // lockInfo is a new attribute added in 1.6 ThreadInfo

            // If cd is a 5.0 version, construct the LockInfo object

            //  from the lockName value.

            if (lockName != null) {

                String result[] = lockName.split("@");

                if (result.length == 2) {

                    int identityHashCode = Integer.parseInt(result[1], 16);

                    lock = new LockInfo(result[0], identityHashCode);

                } else {

                    assert result.length == 2;

                    lock = null;

                }

            } else {

                lock = null;

            }

            lockedMonitors = EMPTY_MONITORS;

            lockedSynchronizers = EMPTY_SYNCS;

        }

    }

    /**

     * Returns the ID of the thread associated with this <tt>ThreadInfo</tt>.

     *

     * @return the ID of the associated thread.

     */

    public long getThreadId() {

        return threadId;

    }

    /**

     * Returns the name of the thread associated with this <tt>ThreadInfo</tt>.

     *

     * @return the name of the associated thread.

     */

    public String getThreadName() {

        return threadName;

    }

    /**

     * Returns the state of the thread associated with this <tt>ThreadInfo</tt>.

     *

     * @return <tt>Thread.State</tt> of the associated thread.

     */

    public Thread.State getThreadState() {

         return threadState;

    }

    /**

     * Returns the approximate accumulated elapsed time (in milliseconds)

     * that the thread associated with this <tt>ThreadInfo</tt>

     * has blocked to enter or reenter a monitor

     * since thread contention monitoring is enabled.

     * I.e. the total accumulated time the thread has been in the

     * {@link java.lang.Thread.State#BLOCKED BLOCKED} state since thread

     * contention monitoring was last enabled.

     * This method returns <tt>-1</tt> if thread contention monitoring

     * is disabled.

     *

     * <p>The Java virtual machine may measure the time with a high

     * resolution timer.  This statistic is reset when

     * the thread contention monitoring is reenabled.

     *

     * @return the approximate accumulated elapsed time in milliseconds

     * that a thread entered the <tt>BLOCKED</tt> state;

     * <tt>-1</tt> if thread contention monitoring is disabled.

     *

     * @throws java.lang.UnsupportedOperationException if the Java

     * virtual machine does not support this operation.

     *

     * @see ThreadMXBean#isThreadContentionMonitoringSupported

     * @see ThreadMXBean#setThreadContentionMonitoringEnabled

     */

    public long getBlockedTime() {

        return blockedTime;

    }

    /**

     * Returns the total number of times that

     * the thread associated with this <tt>ThreadInfo</tt>

     * blocked to enter or reenter a monitor.

     * I.e. the number of times a thread has been in the

     * {@link java.lang.Thread.State#BLOCKED BLOCKED} state.

     *

     * @return the total number of times that the thread

     * entered the <tt>BLOCKED</tt> state.

     */

    public long getBlockedCount() {

        return blockedCount;

    }

    /**

     * Returns the approximate accumulated elapsed time (in milliseconds)

     * that the thread associated with this <tt>ThreadInfo</tt>

     * has waited for notification

     * since thread contention monitoring is enabled.

     * I.e. the total accumulated time the thread has been in the

     * {@link java.lang.Thread.State#WAITING WAITING}

     * or {@link java.lang.Thread.State#TIMED_WAITING TIMED_WAITING} state

     * since thread contention monitoring is enabled.

     * This method returns <tt>-1</tt> if thread contention monitoring

     * is disabled.

     *

     * <p>The Java virtual machine may measure the time with a high

     * resolution timer.  This statistic is reset when

     * the thread contention monitoring is reenabled.

     *

     * @return the approximate accumulated elapsed time in milliseconds

     * that a thread has been in the <tt>WAITING</tt> or

     * <tt>TIMED_WAITING</tt> state;

     * <tt>-1</tt> if thread contention monitoring is disabled.

     *

     * @throws java.lang.UnsupportedOperationException if the Java

     * virtual machine does not support this operation.

     *

     * @see ThreadMXBean#isThreadContentionMonitoringSupported

     * @see ThreadMXBean#setThreadContentionMonitoringEnabled

     */

    public long getWaitedTime() {

        return waitedTime;

    }

    /**

     * Returns the total number of times that

     * the thread associated with this <tt>ThreadInfo</tt>

     * waited for notification.

     * I.e. the number of times that a thread has been

     * in the {@link java.lang.Thread.State#WAITING WAITING}

     * or {@link java.lang.Thread.State#TIMED_WAITING TIMED_WAITING} state.

     *

     * @return the total number of times that the thread

     * was in the <tt>WAITING</tt> or <tt>TIMED_WAITING</tt> state.

     */

    public long getWaitedCount() {

        return waitedCount;

    }

    /**

     * Returns the <tt>LockInfo</tt> of an object for which

     * the thread associated with this <tt>ThreadInfo</tt>

     * is blocked waiting.

     * A thread can be blocked waiting for one of the following:

     * <ul>

     * <li>an object monitor to be acquired for entering or reentering

     *     a synchronization block/method.

     *     <br>The thread is in the {@link java.lang.Thread.State#BLOCKED BLOCKED}

     *     state waiting to enter the <tt>synchronized</tt> statement

     *     or method.

     *     <p></li>

     * <li>an object monitor to be notified by another thread.

     *     <br>The thread is in the {@link java.lang.Thread.State#WAITING WAITING}

     *     or {@link java.lang.Thread.State#TIMED_WAITING TIMED_WAITING} state

     *     due to a call to the {@link Object#wait Object.wait} method.

     *     <p></li>

     * <li>a synchronization object responsible for the thread parking.

     *     <br>The thread is in the {@link java.lang.Thread.State#WAITING WAITING}

     *     or {@link java.lang.Thread.State#TIMED_WAITING TIMED_WAITING} state

     *     due to a call to the

     *     {@link java.util.concurrent.locks.LockSupport#park(Object)

     *     LockSupport.park} method.  The synchronization object

     *     is the object returned from

     *     {@link java.util.concurrent.locks.LockSupport#getBlocker

     *     LockSupport.getBlocker} method. Typically it is an

     *     <a href="LockInfo.html#OwnableSynchronizer"> ownable synchronizer</a>

     *     or a {@link java.util.concurrent.locks.Condition Condition}.</li>

     * </ul>

     *

     * <p>This method returns <tt>null</tt> if the thread is not in any of

     * the above conditions.

     *

     * @return <tt>LockInfo</tt> of an object for which the thread

     *         is blocked waiting if any; <tt>null</tt> otherwise.

     * @since 1.6

     */

    public LockInfo getLockInfo() {

        return lock;

    }

    /**

     * Returns the {@link LockInfo#toString string representation}

     * of an object for which the thread associated with this

     * <tt>ThreadInfo</tt> is blocked waiting.

     * This method is equivalent to calling:

     * <blockquote>

     * <pre>

     * getLockInfo().toString()

     * </pre></blockquote>

     *

     * <p>This method will return <tt>null</tt> if this thread is not blocked

     * waiting for any object or if the object is not owned by any thread.

     *

     * @return the string representation of the object on which

     * the thread is blocked if any;

     * <tt>null</tt> otherwise.

     *

     * @see #getLockInfo

     */

    public String getLockName() {

        return lockName;

    }

    /**

     * Returns the ID of the thread which owns the object

     * for which the thread associated with this <tt>ThreadInfo</tt>

     * is blocked waiting.

     * This method will return <tt>-1</tt> if this thread is not blocked

     * waiting for any object or if the object is not owned by any thread.

     *

     * @return the thread ID of the owner thread of the object

     * this thread is blocked on;

     * <tt>-1</tt> if this thread is not blocked

     * or if the object lis not owned by any thread.

     *

     * @see #getLockInfo

     */

    public long getLockOwnerId() {

        return lockOwnerId;

    }

    /**

     * Returns the name of the thread which owns the object

     * for which the thread associated with this <tt>ThreadInfo</tt>

     * is blocked waiting.

     * This method will return <tt>null</tt> if this thread is not blocked

     * waiting for any object or if the object is not owned by any thread.

     *

     * @return the name of the thread that owns the object

     * this thread is blocked on;

     * <tt>null</tt> if this thread is not blocked

     * or if the object is not owned by any thread.

     *

     * @see #getLockInfo

     */

    public String getLockOwnerName() {

        return lockOwnerName;

    }

    /**

     * Returns the stack trace of the thread

     * associated with this <tt>ThreadInfo</tt>.

     * If no stack trace was requested for this thread info, this method

     * will return a zero-length array.

     * If the returned array is of non-zero length then the first element of

     * the array represents the top of the stack, which is the most recent