DeadLockDetector.java

/*
 * This program 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 3 of the License, or (at your option) any later
 * version.
 * 
 * This program 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
 * this program. If not, see <http://www.gnu.org/licenses/>.
 */

import java.lang.management.LockInfo;
import java.lang.management.ManagementFactory;
import java.lang.management.MonitorInfo;
import java.lang.management.ThreadInfo;
import java.lang.management.ThreadMXBean;
import java.util.logging.Level;
import java.util.logging.Logger;

/**
 * @author -Nemesiss- L2M
 * 
 */
public class DeadLockDetector extends Thread {
    private static Logger      _log       = Logger.getLogger("Minecraft");

    private static final int   _sleepTime = 5 * 1000;

    private final ThreadMXBean tmx;

    public DeadLockDetector() {
        super("DeadLockDetector");
        tmx = ManagementFactory.getThreadMXBean();
        _log.info("hMod: Deadlock Detector Thread initialized.");
    }

    @Override
    public final void run() {
        boolean deadlock = false;
        while (!deadlock)
            try {
                long[] ids = tmx.findDeadlockedThreads();

                if (ids != null) {
                    deadlock = true;
                    ThreadInfo[] tis = tmx.getThreadInfo(ids, true, true);
                    String info = "DeadLock Found!\n";
                    for (ThreadInfo ti : tis)
                        info += ti.toString();

                    for (ThreadInfo ti : tis) {
                        LockInfo[] locks = ti.getLockedSynchronizers();
                        MonitorInfo[] monitors = ti.getLockedMonitors();
                        if (locks.length == 0 && monitors.length == 0)
                            continue;

                        ThreadInfo dl = ti;
                        info += "Java-level deadlock:\n";
                        info += "\t" + dl.getThreadName() + " is waiting to lock " + dl.getLockInfo().toString() + " which is held by " + dl.getLockOwnerName() + "\n";
                        while ((dl = tmx.getThreadInfo(new long[] { dl.getLockOwnerId() }, true, true)[0]).getThreadId() != ti.getThreadId())
                            info += "\t" + dl.getThreadName() + " is waiting to lock " + dl.getLockInfo().toString() + " which is held by " + dl.getLockOwnerName() + "\n";
                    }
                    _log.warning(info);
                }
                Thread.sleep(_sleepTime);
            } catch (Exception e) {
                _log.log(Level.WARNING, "DeadLockDetector: ", e);
            }
    }
}