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Ant example source code file (

This example Ant source code file ( is included in the "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" TM.

Java - Ant tags/keywords

already, buildexception, buildexception, exception, exception, executewatchdog, executewatchdog, illegalstateexception, illegalthreadstateexception, nullpointerexception, process, timeoutobserver, watchdog, watchdog

The source code

 *  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
 *  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.



 * Destroys a process running for too long.
 * For example:
 * <pre>
 * ExecuteWatchdog watchdog = new ExecuteWatchdog(30000);
 * Execute exec = new Execute(myloghandler, watchdog);
 * exec.setCommandLine(mycmdline);
 * int exitvalue = exec.execute();
 * if (Execute.isFailure(exitvalue) && watchdog.killedProcess()) {
 *              // it was killed on purpose by the watchdog
 * }
 * </pre>

 * @see Execute
 * @see
 * @since Ant 1.2
public class ExecuteWatchdog implements TimeoutObserver {

    /** the process to execute and watch for duration */
    private Process process;

    /** say whether or not the watchdog is currently monitoring a process */
    private volatile boolean watch = false;

    /** exception that might be thrown during the process execution */
    private Exception caught = null;

    /** say whether or not the process was killed due to running overtime */
    private volatile boolean killedProcess = false;

    /** will tell us whether timeout has occurred */
    private Watchdog watchdog;

     * Creates a new watchdog with a given timeout.
     * @param timeout the timeout for the process in milliseconds.
     * It must be greater than 0.
    public ExecuteWatchdog(long timeout) {
        watchdog = new Watchdog(timeout);

     * @param timeout the timeout value to use in milliseconds.
     * @see #ExecuteWatchdog(long)
     * @deprecated since 1.5.x.
     *             Use constructor with a long type instead.
     * (1.4.x compatibility)
    public ExecuteWatchdog(int timeout) {
        this((long) timeout);

     * Watches the given process and terminates it, if it runs for too long.
     * All information from the previous run are reset.
     * @param process the process to monitor. It cannot be <tt>null
     * @throws IllegalStateException if a process is still being monitored.
    public synchronized void start(Process process) {
        if (process == null) {
            throw new NullPointerException("process is null.");
        if (this.process != null) {
            throw new IllegalStateException("Already running.");
        this.caught = null;
        this.killedProcess = false; = true;
        this.process = process;

     * Stops the watcher. It will notify all threads possibly waiting
     * on this object.
    public synchronized void stop() {

     * Called after watchdog has finished.
     * This can be called in the watchdog thread
     * @param w the watchdog
    public synchronized void timeoutOccured(Watchdog w) {
        try {
            try {
                // We must check if the process was not stopped
                // before being here
            } catch (IllegalThreadStateException itse) {
                // the process is not terminated, if this is really
                // a timeout and not a manual stop then kill it.
                if (watch) {
                    killedProcess = true;
        } catch (Exception e) {
            caught = e;
        } finally {

     * reset the monitor flag and the process.
    protected synchronized void cleanUp() {
        watch = false;
        process = null;

     * This method will rethrow the exception that was possibly caught during
     * the run of the process. It will only remains valid once the process has
     * been terminated either by 'error', timeout or manual intervention.
     * Information will be discarded once a new process is ran.
     * @throws  BuildException  a wrapped exception over the one that was
     * silently swallowed and stored during the process run.
    public synchronized void checkException() throws BuildException {
        if (caught != null) {
            throw new BuildException("Exception in "
                                     + caught.getMessage(), caught);

     * Indicates whether or not the watchdog is still monitoring the process.
     * @return  <tt>true if the process is still running, otherwise
     *          <tt>false.
    public boolean isWatching() {
        return watch;

     * Indicates whether the last process run was killed on timeout or not.
     * @return  <tt>true if the process was killed otherwise
     *          <tt>false.
    public boolean killedProcess() {
        return killedProcess;

Other Ant examples (source code examples)

Here is a short list of links related to this Ant source code file:

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