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+/* VMThreadMXBeanImpl.java - VM impl. of a thread bean
+ Copyright (C) 2006 Free Software Foundation
+
+This file is part of GNU Classpath.
+
+GNU Classpath is free software; you can redistribute it and/or modify
+it under the terms of the GNU General Public License as published by
+the Free Software Foundation; either version 2, or (at your option)
+any later version.
+
+GNU Classpath 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 for more details.
+
+You should have received a copy of the GNU General Public License
+along with GNU Classpath; see the file COPYING. If not, write to the
+Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
+02110-1301 USA.
+
+Linking this library statically or dynamically with other modules is
+making a combined work based on this library. Thus, the terms and
+conditions of the GNU General Public License cover the whole
+combination.
+
+As a special exception, the copyright holders of this library give you
+permission to link this library with independent modules to produce an
+executable, regardless of the license terms of these independent
+modules, and to copy and distribute the resulting executable under
+terms of your choice, provided that you also meet, for each linked
+independent module, the terms and conditions of the license of that
+module. An independent module is a module which is not derived from
+or based on this library. If you modify this library, you may extend
+this exception to your version of the library, but you are not
+obligated to do so. If you do not wish to do so, delete this
+exception statement from your version. */
+
+package gnu.java.lang.management;
+
+import java.lang.management.ThreadInfo;
+
+/**
+ * Provides access to information about the threads
+ * of the virtual machine. An instance of this bean is
+ * obtained by calling
+ * {@link ManagementFactory#getThreadMXBean()}.
+ * See {@link java.lang.management.ThreadMXBean} for
+ * full documentation.
+ *
+ * @author Andrew John Hughes (gnu_andrew@member.fsf.org)
+ * @since 1.5
+ */
+final class VMThreadMXBeanImpl
+{
+
+ /**
+ * Cache of how many threads were found.
+ */
+ private static int filled;
+
+ /**
+ * Returns the ids of cycles of deadlocked threads, occurring
+ * due to monitor ownership or ownable synchronizer ownership.
+ * This will only be called if ownable synchronizer monitoring
+ * is supported.
+ *
+ * @return the ids of the deadlocked threads.
+ */
+ static native long[] findDeadlockedThreads();
+
+ /**
+ * Returns the ids of cycles of deadlocked threads, occurring
+ * due to monitor ownership.
+ *
+ * @return the ids of the deadlocked threads.
+ */
+ static native long[] findMonitorDeadlockedThreads();
+
+ /* This is the same as in Thread.getAllStackTraces() */
+ static Thread[] getAllThreads()
+ {
+ ThreadGroup group = Thread.currentThread().getThreadGroup();
+ while (group.getParent() != null)
+ group = group.getParent();
+ int arraySize = group.activeCount();
+ Thread[] threadList = new Thread[arraySize];
+ filled = group.enumerate(threadList);
+ while (filled == arraySize)
+ {
+ arraySize *= 2;
+ threadList = new Thread[arraySize];
+ filled = group.enumerate(threadList);
+ }
+ return threadList;
+ }
+
+ /**
+ * Returns the id of all live threads at the time of execution.
+ *
+ * @return the live thread ids.
+ */
+ static long[] getAllThreadIds()
+ {
+ Thread[] threadList = getAllThreads();
+ long[] ids = new long[filled];
+ for (int a = 0; a < filled; ++a)
+ ids[a] = threadList[a].getId();
+ return ids;
+ }
+
+ /**
+ * Returns the number of nanoseconds of CPU time
+ * the current thread has used in total. This is
+ * only called if this feature is enabled and
+ * supported.
+ *
+ * @return the nanoseconds of CPU time used by
+ * the current thread.
+ */
+ static native long getCurrentThreadCpuTime();
+
+ /**
+ * Returns the number of nanoseconds of user time
+ * the current thread has used in total. This is
+ * only called if this feature is enabled and
+ * supported.
+ *
+ * @return the nanoseconds of user time used by
+ * the current thread.
+ */
+ static native long getCurrentThreadUserTime();
+
+ /**
+ * Returns the number of live daemon threads.
+ *
+ * @return the number of live daemon threads.
+ */
+ static int getDaemonThreadCount()
+ {
+ Thread[] threadList = getAllThreads();
+ int daemonCount = 0;
+ for (int a = 0; a < filled; ++a)
+ {
+ if (threadList[a].isDaemon())
+ ++daemonCount;
+ }
+ return daemonCount;
+ }
+
+ /**
+ * Fill out the given {@link ThreadInfo} object
+ * with ownable synchronizer usage information.
+ * This is only called if ownable synchronizer
+ * usage monitoring is supported.
+ *
+ * @param info the {@link ThreadInfo} object to modify.
+ */
+ static native void getLockInfo(ThreadInfo info);
+
+ /**
+ * Fill out the given {@link ThreadInfo} object
+ * with monitor usage information. This is only
+ * called if monitor usage monitoring is supported.
+ *
+ * @param info the {@link ThreadInfo} object to modify.
+ */
+ static native void getMonitorInfo(ThreadInfo info);
+
+ /**
+ * Returns the current peak number of live threads.
+ *
+ * @return the peak number of live threads.
+ */
+ static native int getPeakThreadCount();
+
+ /**
+ * Returns the number of live threads.
+ *
+ * @return the number of live threads.
+ */
+ static int getThreadCount()
+ {
+ getAllThreads();
+ return filled;
+ }
+
+ /**
+ * Returns the number of nanoseconds of CPU time
+ * the specified thread has used in total. This is
+ * only called if this feature is enabled and
+ * supported.
+ *
+ * @param id the thread to obtain statistics on.
+ * @return the nanoseconds of CPU time used by
+ * the thread.
+ */
+ static native long getThreadCpuTime(long id);
+
+ /**
+ * Returns the {@link java.lang.management.ThreadInfo}
+ * which corresponds to the specified id.
+ *
+ * @param id the id of the thread.
+ * @param maxDepth the depth of the stack trace.
+ * @return the corresponding <code>ThreadInfo</code>.
+ */
+ static native ThreadInfo getThreadInfoForId(long id, int maxDepth);
+
+ /**
+ * Returns the number of nanoseconds of user time
+ * the specified thread has used in total. This is
+ * only called if this feature is enabled and
+ * supported.
+ *
+ * @param id the thread to obtain statistics on.
+ * @return the nanoseconds of user time used by
+ * the thread.
+ */
+ static native long getThreadUserTime(long id);
+
+ /**
+ * Returns the total number of threads that have
+ * been started over the lifetime of the virtual
+ * machine.
+ *
+ * @return the total number of threads started.
+ */
+ static native long getTotalStartedThreadCount();
+
+ /**
+ * Resets the peak thread count to the current
+ * number of live threads.
+ */
+ static native void resetPeakThreadCount();
+
+}