| /******************************************************************************* |
| * Copyright (c) 2000, 2005 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 Corporation - initial API and implementation |
| *******************************************************************************/ |
| package org.eclipse.swt.internal; |
| |
| /** |
| * Instance of this represent a recursive monitor. |
| */ |
| public class Lock { |
| int count, waitCount; |
| Thread owner; |
| |
| /** |
| * Locks the monitor and returns the lock count. If |
| * the lock is owned by another thread, wait until |
| * the lock is released. |
| * |
| * @return the lock count |
| */ |
| public int lock() { |
| synchronized (this) { |
| Thread current = Thread.currentThread(); |
| if (owner != current) { |
| waitCount++; |
| while (count > 0) { |
| try { |
| wait(); |
| } catch (InterruptedException e) { |
| /* Wait forever, just like synchronized blocks */ |
| } |
| } |
| --waitCount; |
| owner = current; |
| } |
| return ++count; |
| } |
| } |
| |
| /** |
| * Unlocks the monitor. If the current thread is not |
| * the monitor owner, do nothing. |
| */ |
| public void unlock() { |
| synchronized (this) { |
| Thread current = Thread.currentThread(); |
| if (owner == current) { |
| if (--count == 0) { |
| owner = null; |
| if (waitCount > 0) notifyAll(); |
| } |
| } |
| } |
| } |
| } |