1 /* 2 * Copyright 2009 Red Hat, Inc. 3 * 4 * Red Hat licenses this file to you under the Apache License, version 2.0 5 * (the "License"); you may not use this file except in compliance with the 6 * License. You may obtain a copy of the License at: 7 * 8 * http://www.apache.org/licenses/LICENSE-2.0 9 * 10 * Unless required by applicable law or agreed to in writing, software 11 * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT 12 * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the 13 * License for the specific language governing permissions and limitations 14 * under the License. 15 */ 16 package org.jboss.netty.util.internal; 17 18 import java.util.concurrent.Executor; 19 20 /** 21 * @author <a href="http://gleamynode.net/">Trustin Lee</a> 22 * @version $Rev: 2080 $, $Date: 2010-01-26 18:04:19 +0900 (Tue, 26 Jan 2010) $ 23 */ 24 public final class DeadLockProofWorker { 25 26 /** 27 * An <em>internal use only</em> thread-local variable that tells the 28 * {@link Executor} that this worker acquired a worker thread from. 29 */ 30 public static final ThreadLocal<Executor> PARENT = new ThreadLocal<Executor>(); 31 32 public static void start(final Executor parent, final Runnable runnable) { 33 if (parent == null) { 34 throw new NullPointerException("parent"); 35 } 36 if (runnable == null) { 37 throw new NullPointerException("runnable"); 38 } 39 40 parent.execute(new Runnable() { 41 public void run() { 42 PARENT.set(parent); 43 try { 44 runnable.run(); 45 } finally { 46 PARENT.remove(); 47 } 48 } 49 }); 50 } 51 52 private DeadLockProofWorker() { 53 super(); 54 } 55 }