oracle.toplink.essentials.internal.helper.DeferredLockManager Maven / Gradle / Ivy
/*
* The contents of this file are subject to the terms
* of the Common Development and Distribution License
* (the "License"). You may not use this file except
* in compliance with the License.
*
* You can obtain a copy of the license at
* glassfish/bootstrap/legal/CDDLv1.0.txt or
* https://glassfish.dev.java.net/public/CDDLv1.0.html.
* See the License for the specific language governing
* permissions and limitations under the License.
*
* When distributing Covered Code, include this CDDL
* HEADER in each file and include the License file at
* glassfish/bootstrap/legal/CDDLv1.0.txt. If applicable,
* add the following below this CDDL HEADER, with the
* fields enclosed by brackets "[]" replaced with your
* own identifying information: Portions Copyright [yyyy]
* [name of copyright owner]
*/
// Copyright (c) 1998, 2007, Oracle. All rights reserved.
package oracle.toplink.essentials.internal.helper;
import java.util.*;
/**
* INTERNAL:
*
* Purpose: Be used for deadlock avoidance through allowing detection and resolution.
*
*
* Responsibilities:
*
* - Keep track of all deferred locks of each thread.
*
- Keep track of all active locks of each thread..
*
- Maintain the depth of the each thread.
*
*/
public class DeferredLockManager {
protected Vector deferredLocks;
protected Vector activeLocks;
protected int threadDepth;
protected boolean isThreadComplete;
public static boolean SHOULD_USE_DEFERRED_LOCKS = true;
/**
* DeferredLockManager constructor comment.
*/
public DeferredLockManager() {
super();
this.deferredLocks = new Vector(1);
this.activeLocks = new Vector(1);
this.threadDepth = 0;
this.isThreadComplete = false;
}
/**
* add a concurrency manager as active locks to the DLM
*/
public void addActiveLock(Object manager) {
getActiveLocks().addElement(manager);
}
/**
* add a concurrency manager as deferred locks to the DLM
*/
public void addDeferredLock(Object manager) {
getDeferredLocks().addElement(manager);
}
/**
* decrement the depth of the thread
*/
public void decrementDepth() {
threadDepth--;
}
/**
* Return a set of the active locks from the DLM
*/
public Vector getActiveLocks() {
return activeLocks;
}
/**
* Return a set of the deferred locks
*/
public Vector getDeferredLocks() {
return deferredLocks;
}
/**
* Return the depth of the thread associated with the DLM, being used to release the lock
*/
public int getThreadDepth() {
return threadDepth;
}
/**
* Return if there are any deferred locks.
*/
public boolean hasDeferredLock() {
return !getDeferredLocks().isEmpty();
}
/**
* increment the depth of the thread
*/
public void incrementDepth() {
threadDepth++;
}
/**
* Return if the thread is complete
*/
public boolean isThreadComplete() {
return isThreadComplete;
}
/**
* Release the active lock on the DLM
*/
public void releaseActiveLocksOnThread() {
Vector activeLocks = getActiveLocks();
if (!activeLocks.isEmpty()) {
for (Enumeration activeLocksEnum = activeLocks.elements();
activeLocksEnum.hasMoreElements();) {
ConcurrencyManager manager = (ConcurrencyManager)activeLocksEnum.nextElement();
manager.release();
}
}
setIsThreadComplete(true);
}
/**
* set a set of the active locks to the DLM
*/
public void setActiveLocks(Vector activeLocks) {
this.activeLocks = activeLocks;
}
/**
* set a set of the deferred locks to the DLM
*/
public void setDeferredLocks(Vector deferredLocks) {
this.deferredLocks = deferredLocks;
}
/**
* set if the thread is complete in the given DLM
*/
public void setIsThreadComplete(boolean isThreadComplete) {
this.isThreadComplete = isThreadComplete;
}
}