com.orientechnologies.common.concur.lock.OAdaptiveLock Maven / Gradle / Ivy
/*
*
* * Copyright 2014 Orient Technologies LTD (info(at)orientechnologies.com)
* *
* * 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.
* *
* * For more information: http://www.orientechnologies.com
*
*/
package com.orientechnologies.common.concur.lock;
import com.orientechnologies.common.concur.OTimeoutException;
import java.io.PrintWriter;
import java.io.StringWriter;
import java.lang.reflect.Field;
import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;
import java.util.concurrent.TimeUnit;
import java.util.concurrent.locks.Lock;
import java.util.concurrent.locks.ReentrantLock;
/**
* Adaptive class to handle shared resources. It's configurable specifying if it's running in a concurrent environment and allow o
* specify a maximum timeout to avoid deadlocks.
*
* @author Luca Garulli (l.garulli--at--orientechnologies.com)
*
*/
public class OAdaptiveLock extends OAbstractLock {
private final ReentrantLock lock = new ReentrantLock();
private final boolean concurrent;
private final int timeout;
private final boolean ignoreThreadInterruption;
public OAdaptiveLock() {
this.concurrent = true;
this.timeout = 0;
this.ignoreThreadInterruption = false;
}
public OAdaptiveLock(final int iTimeout) {
this.concurrent = true;
this.timeout = iTimeout;
this.ignoreThreadInterruption = false;
}
public OAdaptiveLock(final boolean iConcurrent) {
this.concurrent = iConcurrent;
this.timeout = 0;
this.ignoreThreadInterruption = false;
}
public OAdaptiveLock(final boolean iConcurrent, final int iTimeout, boolean ignoreThreadInterruption) {
this.concurrent = iConcurrent;
this.timeout = iTimeout;
this.ignoreThreadInterruption = ignoreThreadInterruption;
}
public void lock() {
if (concurrent)
if (timeout > 0) {
try {
if (lock.tryLock(timeout, TimeUnit.MILLISECONDS))
// OK
return;
} catch (InterruptedException e) {
if (ignoreThreadInterruption) {
// IGNORE THE THREAD IS INTERRUPTED: TRY TO RE-LOCK AGAIN
try {
if (lock.tryLock(timeout, TimeUnit.MILLISECONDS)) {
// OK, RESET THE INTERRUPTED STATE
Thread.currentThread().interrupt();
return;
}
} catch (InterruptedException e2) {
Thread.currentThread().interrupt();
}
}
throw new OLockException("Thread interrupted while waiting for resource of class '" + getClass() + "' with timeout="
+ timeout);
}
throwTimeoutException(lock);
} else
lock.lock();
}
public boolean tryAcquireLock() {
return tryAcquireLock(timeout, TimeUnit.MILLISECONDS);
}
public boolean tryAcquireLock(final long iTimeout, final TimeUnit iUnit) {
if (concurrent)
if (timeout > 0)
try {
return lock.tryLock(iTimeout, iUnit);
} catch (InterruptedException e) {
throw new OLockException("Thread interrupted while waiting for resource of class '" + getClass() + "' with timeout="
+ timeout);
}
else
return lock.tryLock();
return true;
}
public void unlock() {
if (concurrent)
lock.unlock();
}
@Override
public void close() {
try {
if (lock.isLocked())
lock.unlock();
} catch (Exception e) {
}
}
private void throwTimeoutException(Lock lock) {
final String owner = extractLockOwnerStackTrace(lock);
throw new OTimeoutException("Timeout on acquiring exclusive lock against resource of class: " + getClass() + " with timeout="
+ timeout + (owner != null ? "\n" + owner : ""));
}
private String extractLockOwnerStackTrace(Lock lock) {
try {
Field syncField = lock.getClass().getDeclaredField("sync");
syncField.setAccessible(true);
Object sync = syncField.get(lock);
Method getOwner = sync.getClass().getSuperclass().getDeclaredMethod("getOwner");
getOwner.setAccessible(true);
final Thread owner = (Thread) getOwner.invoke(sync);
if (owner == null)
return null;
StringWriter stringWriter = new StringWriter();
PrintWriter printWriter = new PrintWriter(stringWriter);
printWriter.append("Owner thread : ").append(owner.toString()).append("\n");
StackTraceElement[] stackTrace = owner.getStackTrace();
for (StackTraceElement traceElement : stackTrace)
printWriter.println("\tat " + traceElement);
printWriter.flush();
return stringWriter.toString();
} catch (RuntimeException e) {
return null;
} catch (NoSuchFieldException e) {
return null;
} catch (IllegalAccessException e) {
return null;
} catch (NoSuchMethodException e) {
return null;
} catch (InvocationTargetException e) {
return null;
}
}
public boolean isConcurrent() {
return concurrent;
}
public ReentrantLock getUnderlying() {
return lock;
}
public boolean isHeldByCurrentThread() {
return lock.isHeldByCurrentThread();
}
}