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Ian Darwin's assorted Java stuff,
assembled as an API.
package com.darwinsys.locks;
import java.util.Date;
import java.util.Map;
/**
* Reaps locks based on their age
*/
public class LockReaperImpl extends Thread {
private static final int DEFAULT_TIMEOUT_MINUTES = 15;
/** Time in MINUTES to expire locks */
private int timeOutMinutes;
/** Time in SECONDS to sleep between runs;
* will not be an exact "interval timer" on most JVMs
*/
private static final int RUN_INTERVAL = 60;
private int sleepSeconds = RUN_INTERVAL;
/** The lock manager that we are part of */
private final PessimisticLockManager mgr;
/** Flag to allow the Thread to terminate when finished */
private boolean done;
/** Construct a Reaper with the default timeout
* @param mgr The lock manager
*/
public LockReaperImpl(PessimisticLockManager mgr) {
this(mgr, DEFAULT_TIMEOUT_MINUTES);
}
/** Construct a Reaper with the given number of
* minutes' timeout
* @param mgr The lock manager
* @param minutes Minutes to timeout
*/
public LockReaperImpl(PessimisticLockManager mgr, int minutes) {
this.timeOutMinutes = minutes;
this.mgr = mgr;
}
/**
* Reap expired locks.
* @see java.lang.Thread#run()
*/
@Override
public void run() {
while (!done) {
timeOutMinutes = mgr.getTimeout(); // update dynamically
Map map = ((PessimisticLockManagerImpl)mgr).getLockStore();
if (map.keySet().size() > 0) {
System.out.println("LockReaper: Locks currently held at " + new Date() + ":");
}
for (Lock lock : map.keySet()) {
@SuppressWarnings("unchecked")
LockImpl l = (LockImpl) lock;
System.out.println("LockReaper: " + l);
final long now = System.currentTimeMillis();
final long then = l.getCreationTime();
if (now - then > timeOutMinutes * 60000) {
System.out.println("LockReaper: Removing stale lock " + l);
mgr.releaseLock(l);
}
}
try {
Thread.sleep(1000 * sleepSeconds);
} catch (InterruptedException e) {
e.printStackTrace();
}
}
}
public void setDone(boolean done) {
this.done = done;
}
}