| /******************************************************************************* |
| * Copyright (c) 2004, 2012 IBM Corporation and others. |
| * All rights reserved. This program and the accompanying materials |
| * are made available under the terms of the Eclipse Public License v1.0 |
| * which accompanies this distribution, and is available at |
| * http://www.eclipse.org/legal/epl-v10.html |
| * |
| * Contributors: |
| * IBM - Initial API and implementation |
| *******************************************************************************/ |
| package org.eclipse.core.runtime.jobs; |
| |
| import org.eclipse.core.internal.jobs.JobManager; |
| import org.eclipse.core.internal.jobs.LockManager; |
| |
| /** |
| * A lock listener is notified whenever a thread is about to wait |
| * on a lock, and when a thread is about to release a lock. |
| * <p> |
| * This class is for internal use by the platform-related plug-ins. |
| * Clients outside of the base platform should not reference or subclass this class. |
| * </p> |
| * |
| * @see IJobManager#setLockListener(LockListener) |
| * @since 3.0 |
| */ |
| public class LockListener { |
| private final LockManager manager = ((JobManager) Job.getJobManager()).getLockManager(); |
| |
| /** |
| * Notification that a thread is about to block on an attempt to acquire a lock. |
| * Returns whether the thread should be granted immediate access to the lock. |
| * <p> |
| * This default implementation always returns <code>false</code>. |
| * Subclasses may override. |
| * |
| * @param lockOwner the thread that currently owns the lock this thread is |
| * waiting for, or <code>null</code> if unknown. |
| * @return <code>true</code> if the thread should be granted immediate access, |
| * and <code>false</code> if it should wait for the lock to be available |
| */ |
| public boolean aboutToWait(Thread lockOwner) { |
| return false; |
| } |
| |
| /** |
| * Notification that a thread is about to release a lock. |
| * <p> |
| * This default implementation does nothing. Subclasses may override. |
| */ |
| public void aboutToRelease() { |
| //do nothing |
| } |
| |
| /** |
| * Returns if it is safe for the calling thread to block while waiting to obtain |
| * a lock. When blocking in the calling thread is not safe, the caller will ensure |
| * that the thread is kept alive and responsive to cancellation while waiting. |
| * |
| * @return <code>true</code> if this thread can block, and |
| * <code>false</code> otherwise. |
| * |
| * @since org.eclipse.core.jobs 3.5 |
| */ |
| public boolean canBlock() { |
| return true; |
| } |
| |
| /** |
| * Returns whether this thread currently owns any locks |
| * @return <code>true</code> if this thread owns any locks, and |
| * <code>false</code> otherwise. |
| */ |
| protected final boolean isLockOwnerThread() { |
| return manager.isLockOwner(); |
| } |
| } |