strolch/xmlpers/src/main/java/li/strolch/xmlpers/objref/LockableObject.java

125 lines
3.5 KiB
Java

/*
* Copyright 2013 Robert von Burg <eitch@eitchnet.ch>
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package li.strolch.xmlpers.objref;
import static java.lang.Thread.currentThread;
import static java.text.MessageFormat.format;
import static li.strolch.utils.helper.StringHelper.formatMillisecondsDuration;
import java.text.MessageFormat;
import java.util.Collection;
import java.util.concurrent.TimeUnit;
import java.util.concurrent.locks.ReentrantLock;
import li.strolch.xmlpers.api.XmlPersistenceException;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
public class LockableObject {
private static final Logger logger = LoggerFactory.getLogger(LockableObject.class);
private static long tryLockTime = 10000L;
public static void setTryLockTime(long tryLockTime) {
LockableObject.tryLockTime = tryLockTime;
}
private final Lock lock;
protected final String name;
public LockableObject(String name) {
this.name = name;
this.lock = new Lock(true);
}
public String getName() {
return this.name;
}
public static long getLockTime() {
return tryLockTime;
}
/**
* @see java.util.concurrent.locks.ReentrantLock#tryLock(long, TimeUnit)
*/
public void lock() {
// don't lock multiple times
if (this.lock.isHeldByCurrentThread() && this.lock.isLocked())
return;
try {
if (!this.lock.tryLock(tryLockTime, TimeUnit.MILLISECONDS)) {
String msg = "Thread {0} failed to acquire lock after {1} for {2}"; //$NON-NLS-1$
msg = format(msg, currentThread().getName(), formatMillisecondsDuration(tryLockTime), this);
Thread owner = lock.getOwner();
if (owner == null) {
logger.error(MessageFormat.format("Lock {0} is currently held unknown thread!", this.name));
logger.error(lock.toString());
} else {
Exception e = new Exception();
e.setStackTrace(owner.getStackTrace());
logger.error(MessageFormat.format("Lock {0} is currently held by {1}", this.name, owner), e);
}
logger.error("Threads waiting on this lock are:");
for (Thread queuedThread : lock.getQueuedThreads()) {
Exception e = new Exception();
e.setStackTrace(queuedThread.getStackTrace());
logger.error("\n" + queuedThread.getName(), e);
}
throw new XmlPersistenceException(msg);
}
if (logger.isDebugEnabled())
logger.debug("locked " + toString()); //$NON-NLS-1$
} catch (InterruptedException e) {
throw new XmlPersistenceException("Thread interrupted: " + e.getMessage(), e); //$NON-NLS-1$
}
}
/**
* @see java.util.concurrent.locks.ReentrantLock#unlock()
*/
public void releaseLock() {
while (this.lock.isHeldByCurrentThread() && this.lock.isLocked()) {
if (logger.isDebugEnabled())
logger.debug("unlocking " + toString()); //$NON-NLS-1$
this.lock.unlock();
}
}
public static class Lock extends ReentrantLock {
public Lock(boolean fair) {
super(fair);
}
@Override
public Thread getOwner() {
return super.getOwner();
}
@Override
public Collection<Thread> getQueuedThreads() {
return super.getQueuedThreads();
}
}
}