diff options
Diffstat (limited to 'libjava/classpath/java/lang/management/ThreadMXBean.java')
| -rw-r--r-- | libjava/classpath/java/lang/management/ThreadMXBean.java | 167 |
1 files changed, 156 insertions, 11 deletions
diff --git a/libjava/classpath/java/lang/management/ThreadMXBean.java b/libjava/classpath/java/lang/management/ThreadMXBean.java index 669cb3cd8d2..f73075dfdc2 100644 --- a/libjava/classpath/java/lang/management/ThreadMXBean.java +++ b/libjava/classpath/java/lang/management/ThreadMXBean.java @@ -57,20 +57,30 @@ package java.lang.management; * <p> * This bean supports some optional behaviour, which all * virtual machines may not choose to implement. Specifically, - * this includes the monitoring of the CPU time used by a - * thread, and the monitoring of thread contention. The former - * is further subdivided into the monitoring of either just - * the current thread or all threads. The methods + * this includes the monitoring of: + * </p> + * <ul> + * <li>the CPU time used by a thread</li> + * <li>thread contention</li> + * <li>object monitor usage</li> + * <li>ownable synchronizer usage</li> + * </ul> + * <p> + * The monitoring of CPU time is further subdivided into + * the monitoring of either just the current thread or all + * threads. The methods * {@link #isThreadCpuTimeSupported()}, - * {@link #isCurrentThreadCpuTimeSupported()} and - * {@link #isThreadContentionMonitoringSupported()} may be + * {@link #isCurrentThreadCpuTimeSupported()} + * {@link #isThreadContentionMonitoringSupported()}, + * {@link #isObjectMonitorUsageSupported()} and + * {@link #isSynchronizerUsageSupported()} may be * used to determine whether or not this functionality is * supported. * </p> * <p> - * Furthermore, both these facilities may be disabled. - * In fact, thread contention monitoring is disabled by - * default, and must be explictly turned on by calling + * Furthermore, both time and contention monitoring may be + * disabled. In fact, thread contention monitoring is disabled + * by default, and must be explictly turned on by calling * the {@link #setThreadContentionMonitoringEnabled(boolean)} * method. * </p> @@ -82,6 +92,70 @@ public interface ThreadMXBean { /** + * This method returns information on all live threads at the + * time of execution (some threads may have terminated by the + * time the method completes). This method is simply a shorthand + * for calling {@link #getThreadInfo(long[], boolean, + * boolean)} with the return value of {@link #getAllThreadIds()}. + * + * @param lockedMonitors true if the returned {@link ThreadInfo} + * objects should contain information on + * locked monitors. + * @param lockedSynchronizers true if the returned {@link ThreadInfo} + * objects should contain information + * on locked ownable synchronizers. + * @return an array of {@link ThreadInfo} objects for all live threads. + * @throws SecurityException if a security manager exists and + * denies ManagementPermission("monitor"). + * @throws UnsupportedOperationException if <code>lockedMonitors</code> + * is true, but object monitor + * usage monitoring is not supported + * by the VM, or + * <code>lockedSynchronizers</code> + * is true, but ownable synchronizer + * usage monitoring is not supported + * by the VM. + * @since 1.6 + * @see #getThreadInfo(long[], boolean, boolean) + * @see #getAllThreadIds() + * @see #isObjectMonitorUsageSupported() + * @see #isSynchronizerUsageSupported() + */ + ThreadInfo[] dumpAllThreads(boolean lockedMonitors, + boolean lockedSynchronizers); + + /** + * <p> + * This method obtains a list of threads which are deadlocked + * waiting to obtain monitor or ownable synchronizer ownership. + * This is similar to the behaviour described for + * {@link #getMonitorDeadlockedThreads()}, except this method also + * takes in to account deadlocks involving ownable synchronizers. + * </p> + * <p> + * Note that this method is not designed for controlling + * synchronization, but for troubleshooting problems which cause such + * deadlocks; it may be prohibitively expensive to use in normal + * operation. If only deadlocks involving monitors are of interest, + * then {@link #findMonitorDeadlockedThreads()} should be used in + * preference to this method. + * </p> + * + * @return an array of thread identifiers, corresponding to threads + * which are currently in a deadlocked situation, or + * <code>null</code> if there are no deadlocks. + * @throws SecurityException if a security manager exists and + * denies ManagementPermission("monitor"). + * @throws UnsupportedOperationException if the VM does not support + * the monitoring of ownable + * synchronizer usage. + * @since 1.6 + * @see #findMonitorDeadlockedThreads() + * @see #isSynchronizerUsageSupported() + */ + long[] findDeadlockedThreads(); + + /** * <p> * This method obtains a list of threads which are deadlocked * waiting to obtain monitor ownership. On entering a synchronized @@ -115,13 +189,17 @@ public interface ThreadMXBean * of A and B. Note that this method is not designed for controlling * synchronization, but for troubleshooting problems which cause such * deadlocks; it may be prohibitively expensive to use in normal - * operation. + * operation. This method only returns deadlocks involving monitors; + * to include deadlocks involving ownable synchronizers, + * {@link #findDeadlockedThreads()} should be used instead. * </p> * * @return an array of thread identifiers, corresponding to threads - * which are currently in a deadlocked situation. + * which are currently in a deadlocked situation, or + * <code>null</code> if there are no deadlocks. * @throws SecurityException if a security manager exists and * denies ManagementPermission("monitor"). + * @see #findDeadlockedThreads() */ long[] findMonitorDeadlockedThreads(); @@ -285,6 +363,53 @@ public interface ThreadMXBean ThreadInfo[] getThreadInfo(long[] ids); /** + * Returns information on the specified threads with full + * stack trace information and optional synchronization + * information. If <code>lockedMonitors</code> is false, + * or there are no locked monitors for a particular thread, + * then the corresponding {@link ThreadInfo} object will have + * an empty {@link MonitorInfo} array. Likewise, if + * <code>lockedSynchronizers</code> is false, or there are + * no locked ownable synchronizers for a particular thread, + * then the corresponding {@link ThreadInfo} object will have + * an empty {@link LockInfo} array. If both + * <code>lockedMonitors</code> and <code>lockedSynchronizers</code> + * are false, the return value is equivalent to that from + * <code>{@link #getThreadInfo}(ids, Integer.MAX_VALUE)</code>. + * If an identifier specifies a thread which is either non-existant + * or not alive, then the corresponding element in the returned + * array is <code>null</code>. + * + * @param ids an array of thread identifiers to return information + * on. + * @param lockedMonitors true if information on locked monitors + * should be included. + * @param lockedSynchronizers true if information on locked + * ownable synchronizers should be included. + * @return an array of {@link ThreadInfo} objects matching the + * specified threads. The corresponding element is + * <code>null</code> if the identifier specifies + * a thread that doesn't exist or is not alive. + * @throws IllegalArgumentException if an identifier in the array is + * <= 0. + * @throws SecurityException if a security manager exists and + * denies ManagementPermission("monitor"). + * @throws UnsupportedOperationException if <code>lockedMonitors</code> + * is true, but object monitor + * usage monitoring is not supported + * by the VM, or + * <code>lockedSynchronizers</code> + * is true, but ownable synchronizer + * usage monitoring is not supported + * by the VM. + * @since 1.6 + * @see #isObjectMonitorUsageSupported() + * @see #isSynchronizerUsageSupported() + */ + ThreadInfo[] getThreadInfo(long[] ids, boolean lockedMonitors, + boolean lockedSynchronizers); + + /** * Returns information on the specified thread with * stack trace information to the supplied depth. If the * identifier specifies a thread which is either non-existant @@ -390,6 +515,26 @@ public interface ThreadMXBean boolean isCurrentThreadCpuTimeSupported(); /** + * Returns true if the virtual machine supports the monitoring + * of object monitor usage. + * + * @return true if the monitoring of object monitor usage + * is supported by the virtual machine. + * @since 1.6 + */ + boolean isObjectMonitorUsageSupported(); + + /** + * Returns true if the virtual machine supports the monitoring + * of ownable synchronizer usage. + * + * @return true if the monitoring of ownable synchronizer usage + * is supported by the virtual machine. + * @since 1.6 + */ + boolean isSynchronizerUsageSupported(); + + /** * Returns true if thread contention monitoring is currently * enabled. * |
