| /* |
| * Licensed to the Apache Software Foundation (ASF) under one or more |
| * contributor license agreements. See the NOTICE file distributed with |
| * this work for additional information regarding copyright ownership. |
| * The ASF licenses this file to You under the Apache License, Version 2.0 |
| * (the "License"); you may not use this file except in compliance with |
| * the License. You may obtain a copy of the License at |
| * |
| * http://www.apache.org/licenses/LICENSE-2.0 |
| * |
| * Unless required by applicable law or agreed to in writing, software |
| * distributed under the License is distributed on an "AS IS" BASIS, |
| * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| * See the License for the specific language governing permissions and |
| * limitations under the License. |
| * |
| */ |
| |
| package org.apache.commons.exec; |
| |
| import java.util.Enumeration; |
| import java.util.Vector; |
| |
| /** |
| * Generalization of {@code ExecuteWatchdog} |
| * |
| * @see org.apache.commons.exec.ExecuteWatchdog |
| * |
| */ |
| public class Watchdog implements Runnable { |
| |
| private final Vector<TimeoutObserver> observers = new Vector<TimeoutObserver>(1); |
| |
| private final long timeout; |
| |
| private boolean stopped = false; |
| |
| public Watchdog(final long timeout) { |
| if (timeout < 1) { |
| throw new IllegalArgumentException("timeout must not be less than 1."); |
| } |
| this.timeout = timeout; |
| } |
| |
| public void addTimeoutObserver(final TimeoutObserver to) { |
| observers.addElement(to); |
| } |
| |
| public void removeTimeoutObserver(final TimeoutObserver to) { |
| observers.removeElement(to); |
| } |
| |
| protected final void fireTimeoutOccured() { |
| final Enumeration<TimeoutObserver> e = observers.elements(); |
| while (e.hasMoreElements()) { |
| e.nextElement().timeoutOccured(this); |
| } |
| } |
| |
| public synchronized void start() { |
| stopped = false; |
| final Thread t = new Thread(this, "WATCHDOG"); |
| t.setDaemon(true); |
| t.start(); |
| } |
| |
| public synchronized void stop() { |
| stopped = true; |
| notifyAll(); |
| } |
| |
| public void run() { |
| final long startTime = System.currentTimeMillis(); |
| boolean isWaiting; |
| synchronized (this) { |
| long timeLeft = timeout - (System.currentTimeMillis() - startTime); |
| isWaiting = timeLeft > 0; |
| while (!stopped && isWaiting) { |
| try { |
| wait(timeLeft); |
| } catch (final InterruptedException e) { |
| } |
| timeLeft = timeout - (System.currentTimeMillis() - startTime); |
| isWaiting = timeLeft > 0; |
| } |
| } |
| |
| // notify the listeners outside of the synchronized block (see EXEC-60) |
| if (!isWaiting) { |
| fireTimeoutOccured(); |
| } |
| } |
| |
| } |