| /******************************************************************************* |
| * Copyright (c) 2001, 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 |
| *******************************************************************************/ |
| package org.eclipse.wst.validation.internal; |
| |
| |
| import java.util.Vector; |
| |
| import org.eclipse.core.runtime.IStatus; |
| import org.eclipse.wst.validation.internal.plugin.ValidationPlugin; |
| |
| |
| /** |
| * This class manages (queue, invoke, etc.) the Runnables that perform the validation for a |
| * particular validator. |
| */ |
| public class VThreadManager { |
| private static VThreadManager _manager = null; |
| private static final int MAX_NUM_OF_RESTART = 5; // the maximum number of times that the thread |
| // should attempt to ignore a Throwable and |
| // carry on |
| |
| private Thread _validationThread = null; // This thread checks if the current Runnable is |
| // finished, and if so, loads the first Runnable off of |
| // the queue and starts it. |
| volatile int restart = 0; // how many times has the thread been restarted? |
| volatile Jobs _jobs = null; |
| |
| private VThreadManager() { |
| _jobs = new Jobs(); |
| |
| // Start the validation thread to check for queued ValidationOperation |
| Runnable validationRunnable = new Runnable() { |
| public void run() { |
| while (true) { |
| try { |
| if (restart > MAX_NUM_OF_RESTART) { |
| // something has gone seriously, seriously wrong |
| String message = "restart = " + restart; //$NON-NLS-1$ |
| ValidationPlugin.getPlugin().logMessage(IStatus.ERROR, message); |
| break; |
| } |
| |
| Runnable job = getJobs().dequeue(); // If currentRunnable is null, there's |
| // nothing on the queue. Shouldn't |
| // happen with a semaphore. |
| if (job != null) { |
| getJobs().setActive(true); |
| job.run(); |
| getJobs().setActive(false); |
| } |
| } catch (Exception e) { |
| restart++; |
| getJobs().setActive(false); |
| ValidationPlugin.getPlugin().handleException(e); |
| } finally { |
| //do nothing |
| } |
| } |
| } |
| }; |
| |
| _validationThread = new Thread(validationRunnable, "ValidationThread"); //$NON-NLS-1$ |
| _validationThread.start(); |
| } |
| |
| public static VThreadManager getManager() { |
| if (_manager == null) { |
| _manager = new VThreadManager(); |
| } |
| return _manager; |
| } |
| |
| Jobs getJobs() { |
| return _jobs; |
| } |
| |
| public void queue(Runnable runnable) { |
| getJobs().queue(runnable); |
| } |
| |
| /** |
| * Return true if all of the Runnables have been run. |
| */ |
| public boolean isDone() { |
| return getJobs().isDone(); |
| } |
| |
| private class Jobs { |
| private Vector<Runnable> _queuedJobs; // The queued Runnables that need to be run. |
| private boolean _isActive; // Is a job being run in the validation thread? |
| |
| public Jobs() { |
| _queuedJobs = new Vector<Runnable>(); |
| } |
| |
| public synchronized void queue(Runnable runnable) { |
| // If there is a thread running already, then it must finish before another validation |
| // thread is launched, or the validation messages could reflect the last thread |
| // finished, |
| // instead of the last state of changes. |
| |
| // Have to wait for the current Runnable to finish, so add this to the end of the queue |
| _queuedJobs.add(runnable); |
| notifyAll(); |
| } |
| |
| /** |
| * Pop the Runnable off of the head of the queue. |
| */ |
| synchronized Runnable dequeue() { |
| while (_queuedJobs.size() == 0) { |
| try { |
| wait(); |
| } catch (InterruptedException exc) { |
| //Ignore |
| } |
| } // Block on the semaphore; break when a job has been added to the queue. |
| |
| Runnable job = null; |
| if (_queuedJobs.size() > 0) { |
| job = _queuedJobs.get(0); |
| if (job != null) { |
| _queuedJobs.remove(0); |
| } |
| } |
| return job; |
| } |
| |
| public synchronized boolean isActive() { |
| return _isActive; |
| } |
| |
| public synchronized void setActive(boolean active) { |
| _isActive = active; |
| } |
| |
| /** |
| * Return true if all of the Runnables have been run. |
| */ |
| public synchronized boolean isDone() { |
| return ((_queuedJobs.size() == 0) && !isActive()); |
| } |
| } |
| } |