| /* |
| * Copyright (c) 2008, 2009, 2011, 2012, 2015 Eike Stepper (Berlin, Germany) 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: |
| * Eike Stepper - initial API and implementation |
| */ |
| package org.eclipse.net4j.util.concurrent; |
| |
| import java.util.concurrent.Executor; |
| |
| public class OnePendingExecutor implements Executor |
| { |
| private Runnable command; |
| |
| private Thread thread; |
| |
| public OnePendingExecutor() |
| { |
| } |
| |
| public synchronized void execute(Runnable command) |
| { |
| if (this.command != null) |
| { |
| throw new IllegalStateException("One command already pending"); //$NON-NLS-1$ |
| } |
| |
| this.command = command; |
| if (thread == null) |
| { |
| thread = new Thread() |
| { |
| @Override |
| public void run() |
| { |
| for (;;) |
| { |
| Runnable command; |
| synchronized (OnePendingExecutor.this) |
| { |
| if (OnePendingExecutor.this.command == null) |
| { |
| thread = null; |
| return; |
| } |
| |
| command = OnePendingExecutor.this.command; |
| OnePendingExecutor.this.command = null; |
| } |
| |
| command.run(); |
| } |
| } |
| }; |
| |
| thread.setDaemon(true); |
| thread.start(); |
| } |
| } |
| } |