| /******************************************************************************* |
| * Copyright (c) 2005, 2008 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 |
| * Matthew Hall - bugs 118516, 281723, 286533 |
| *******************************************************************************/ |
| package org.eclipse.core.tests.databinding.observable; |
| |
| import java.util.LinkedList; |
| |
| import org.eclipse.core.databinding.observable.Realm; |
| import org.eclipse.core.runtime.Assert; |
| |
| /** |
| * {@link Realm} that enforces execution to be within a specific |
| * {@link Thread}. |
| * |
| * @since 3.2 |
| */ |
| public class ThreadRealm extends Realm { |
| private Thread thread; |
| |
| private final LinkedList queue = new LinkedList(); |
| |
| private volatile boolean block; |
| |
| /** |
| * Initializes the realm. |
| * |
| * @param thread |
| */ |
| public synchronized void init(Thread thread) { |
| if (thread == null) { |
| throw new IllegalArgumentException("Parameter thread was null."); //$NON-NLS-1$ |
| } |
| Assert.isTrue(this.thread == null, "Realm can only be initialized once."); |
| |
| this.thread = thread; |
| } |
| |
| /** |
| * @return <code>true</code> if the current thread is the thread for |
| * the realm |
| */ |
| public boolean isCurrent() { |
| return Thread.currentThread() == thread; |
| } |
| |
| /** |
| * @return thread, <code>null</code> if not |
| * {@link #init(Thread) initialized} |
| */ |
| public Thread getThread() { |
| return thread; |
| } |
| |
| /** |
| * Queues the provided <code>runnable</code>. |
| * |
| * @param runnable |
| */ |
| public void asyncExec(Runnable runnable) { |
| synchronized (queue) { |
| queue.add(runnable); |
| queue.notifyAll(); |
| } |
| } |
| |
| /** |
| * Returns after the realm has completed all runnables currently on its |
| * queue. Do not call from the realm's thread. |
| * |
| * @throws IllegalStateException |
| * if the ThreadRealm is not blocking on its thread. |
| * @throws IllegalStateException |
| * if invoked from the realm's own thread. |
| */ |
| public void processQueue() { |
| if (Thread.currentThread() == thread) { |
| throw new IllegalStateException( |
| "Cannot execute this method in the realm's own thread"); |
| } |
| |
| try { |
| synchronized (queue) { |
| while (!queue.isEmpty()) { |
| if (!block) |
| throw new IllegalStateException( |
| "Cannot process queue, ThreadRealm is not blocking on its thread"); |
| queue.wait(); |
| } |
| } |
| } catch (InterruptedException e) { |
| Thread.currentThread().interrupt(); |
| } |
| } |
| |
| public boolean isBlocking() { |
| return block; |
| } |
| |
| /** |
| * Blocks the current thread invoking runnables. |
| */ |
| public void block() { |
| if (block) { |
| throw new IllegalStateException("Realm is already blocking."); |
| } |
| |
| if (Thread.currentThread() != thread) { |
| throw new IllegalStateException("The current thread is not the correct thread."); |
| } |
| |
| try { |
| block = true; |
| |
| synchronized (queue) { |
| queue.notifyAll(); // so waitUntilBlocking can return |
| } |
| |
| while (block) { |
| Runnable runnable = null; |
| synchronized (queue) { |
| if (queue.isEmpty()) { |
| queue.wait(); |
| } else { |
| runnable = (Runnable) queue.getFirst(); |
| } |
| } |
| |
| if (runnable != null) { |
| safeRun(runnable); |
| synchronized (queue) { |
| // Don't remove the runnable from the queue until after |
| // it has run, or else processQueue() may return before |
| // the last runnable has finished |
| queue.removeFirst(); |
| queue.notifyAll(); |
| } |
| } |
| } |
| } catch (InterruptedException e) { |
| Thread.currentThread().interrupt(); |
| } finally { |
| block = false; |
| } |
| } |
| |
| /** |
| * Unblocks the thread. |
| */ |
| public void unblock() { |
| block = false; |
| |
| // Awaken the thread if waiting. |
| synchronized (queue) { |
| queue.notifyAll(); |
| } |
| } |
| |
| /** |
| * Blocks until the ThreadRealm is blocking on its own thread. |
| */ |
| public void waitUntilBlocking() { |
| if (Thread.currentThread() == thread) { |
| throw new IllegalStateException( |
| "Cannot execute this method in the realm's own thread"); |
| } |
| |
| while (!block) { |
| synchronized (queue) { |
| try { |
| queue.wait(); |
| } catch (InterruptedException e) { |
| Thread.currentThread().interrupt(); |
| } |
| } |
| } |
| } |
| } |