| /******************************************************************************* |
| * Copyright (c) 2003, 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 Corporation - initial API and implementation |
| * James Blackburn (Broadcom Corp.) - Bug 311863 Ordered Lock lost after interrupt |
| *******************************************************************************/ |
| package org.eclipse.core.internal.jobs; |
| |
| public class Semaphore { |
| protected long notifications; |
| protected Runnable runnable; |
| |
| public Semaphore(Runnable runnable) { |
| this.runnable = runnable; |
| notifications = 0; |
| } |
| |
| /** |
| * Attempts to acquire this semaphore. Returns true if it was successfully acquired, |
| * and false otherwise. |
| */ |
| public synchronized boolean acquire(long delay) throws InterruptedException { |
| if (Thread.interrupted()) |
| throw new InterruptedException(); |
| long start = System.currentTimeMillis(); |
| long timeLeft = delay; |
| while (true) { |
| if (notifications > 0) { |
| notifications--; |
| return true; |
| } |
| if (timeLeft <= 0) |
| return false; |
| wait(timeLeft); |
| timeLeft = start + delay - System.currentTimeMillis(); |
| } |
| } |
| |
| /** |
| * Attempt to acquire the semaphore without waiting. |
| * Returns true if successfully acquired, false otherwise. |
| */ |
| public synchronized boolean attempt() { |
| if (notifications > 0) { |
| notifications--; |
| return true; |
| } |
| return false; |
| } |
| |
| @Override |
| public boolean equals(Object obj) { |
| return (runnable == ((Semaphore) obj).runnable); |
| } |
| |
| @Override |
| public int hashCode() { |
| return runnable == null ? 0 : runnable.hashCode(); |
| } |
| |
| public synchronized void release() { |
| notifications++; |
| notifyAll(); |
| } |
| |
| // for debug only |
| @Override |
| public String toString() { |
| return "Semaphore(" + runnable + ")"; //$NON-NLS-1$ //$NON-NLS-2$ |
| } |
| } |