| /******************************************************************************* |
| * Copyright (c) 2008, 2009 Wind River Systems 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: |
| * Wind River Systems - initial API and implementation |
| * NVIDIA - coalesce runnable in the single event loop iteration |
| *******************************************************************************/ |
| package org.eclipse.cdt.dsf.ui.concurrent; |
| |
| import java.util.Collections; |
| import java.util.HashMap; |
| import java.util.LinkedList; |
| import java.util.Map; |
| import java.util.Queue; |
| import java.util.concurrent.Executor; |
| import java.util.concurrent.RejectedExecutionException; |
| |
| import org.eclipse.cdt.dsf.concurrent.DsfExecutor; |
| import org.eclipse.swt.SWT; |
| import org.eclipse.swt.SWTException; |
| import org.eclipse.swt.widgets.Display; |
| |
| /** |
| * A simple executor which uses the display thread to run the submitted |
| * runnables. It only implements the {@link Executor}, and NOT the more |
| * sophisticated {@link DsfExecutor} (which extends |
| * {@link java.util.concurrent.ScheduledExecutorService}). However, this |
| * implementation is much more efficient than DisplayDsfExecutor as it does |
| * not use a separate thread or maintain its own queue. |
| * |
| * @since 1.0 |
| */ |
| public class SimpleDisplayExecutor implements Executor{ |
| /** |
| * Internal mapping of display objects to executors. |
| */ |
| private static Map<Display, SimpleDisplayExecutor> fExecutors = Collections.synchronizedMap( new HashMap<Display, SimpleDisplayExecutor>() ); |
| |
| /** |
| * Factory method for display executors. |
| * @param display Display to create an executor for. |
| * @return The new (or re-used) executor. |
| */ |
| public static SimpleDisplayExecutor getSimpleDisplayExecutor(final Display display) { |
| synchronized (fExecutors) { |
| SimpleDisplayExecutor executor = fExecutors.get(display); |
| if (executor == null) { |
| executor = new SimpleDisplayExecutor(display); |
| fExecutors.put(display, executor); |
| } |
| return executor; |
| } |
| } |
| |
| /** |
| * The display class used by this executor to execute the submitted runnables. |
| */ |
| private final Display fDisplay; |
| /** |
| * Runnables waiting for the UI loop iteration |
| */ |
| private Queue<Runnable> runnables; |
| |
| private SimpleDisplayExecutor(final Display display) { |
| fDisplay = display; |
| } |
| |
| @Override |
| public void execute(final Runnable command) { |
| final boolean needsPosting = enqueue(command); |
| if (needsPosting) { |
| try { |
| fDisplay.asyncExec(new Runnable() { |
| @Override |
| public void run() { |
| runInSwtThread(); |
| } |
| }); |
| } catch (final SWTException e) { |
| if (e.code == SWT.ERROR_DEVICE_DISPOSED) { |
| throw new RejectedExecutionException("Display " + fDisplay + " is disposed", e); //$NON-NLS-1$ //$NON-NLS-2$ |
| } else { |
| throw e; |
| } |
| } |
| } |
| } |
| |
| private synchronized boolean enqueue(final Runnable runnable) { |
| boolean needsPosting = false; |
| if (runnables == null) { |
| runnables = new LinkedList<Runnable>(); |
| needsPosting = true; |
| } |
| runnables.offer(runnable); |
| return needsPosting; |
| } |
| |
| private synchronized Runnable getNextRunnable() { |
| final Runnable runnable = runnables.poll(); |
| if (runnable == null) { |
| runnables = null; |
| return null; |
| } else { |
| return runnable; |
| } |
| } |
| |
| /** @since 2.3 */ |
| protected void runInSwtThread() { |
| Runnable runnable; |
| while ((runnable = getNextRunnable()) != null) { |
| runnable.run(); |
| } |
| } |
| } |