1 files changed, 128 insertions, 0 deletions
diff --git a/framework/src/ant/apache-ant-1.9.6/src/main/org/apache/tools/ant/util/Watchdog.java b/framework/src/ant/apache-ant-1.9.6/src/main/org/apache/tools/ant/util/Watchdog.java
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+++ b/framework/src/ant/apache-ant-1.9.6/src/main/org/apache/tools/ant/util/Watchdog.java
@@ -0,0 +1,128 @@
+/*
+ *  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.tools.ant.util;
+
+import java.util.Enumeration;
+import java.util.Vector;
+
+/**
+ * Generalization of <code>ExecuteWatchdog</code>
+ *
+ * @since Ant 1.5
+ *
+ * @see org.apache.tools.ant.taskdefs.ExecuteWatchdog
+ *
+ */
+public class Watchdog implements Runnable {
+
+    private Vector observers = new Vector(1);
+    private long timeout = -1;
+    /**
+     * marked as volatile to stop the compiler caching values or (in java1.5+,
+     * reordering access)
+     */
+    private volatile boolean stopped = false;
+    /**
+     * Error string.
+     * {@value}
+     */
+    public static final String ERROR_INVALID_TIMEOUT = "timeout less than 1.";
+
+    /**
+     * Constructor for Watchdog.
+     * @param timeout the timeout to use in milliseconds (must be &gt;= 1).
+     */
+    public Watchdog(long timeout) {
+        if (timeout < 1) {
+            throw new IllegalArgumentException(ERROR_INVALID_TIMEOUT);
+        }
+        this.timeout = timeout;
+    }
+
+    /**
+     * Add a timeout observer.
+     * @param to the timeout observer to add.
+     */
+    public void addTimeoutObserver(TimeoutObserver to) {
+        //no need to synchronize, as Vector is always synchronized
+        observers.addElement(to);
+    }
+
+    /**
+     * Remove a timeout observer.
+     * @param to the timeout observer to remove.
+     */
+    public void removeTimeoutObserver(TimeoutObserver to) {
+        //no need to synchronize, as Vector is always synchronized
+        observers.removeElement(to);
+    }
+
+    /**
+     * Inform the observers that a timeout has occurred.
+     * This happens in the watchdog thread.
+     */
+    protected final void fireTimeoutOccured() {
+        Enumeration e = observers.elements();
+        while (e.hasMoreElements()) {
+            ((TimeoutObserver) e.nextElement()).timeoutOccured(this);
+        }
+    }
+
+    /**
+     * Start the watch dog.
+     */
+    public synchronized void start() {
+        stopped = false;
+        Thread t = new Thread(this, "WATCHDOG");
+        t.setDaemon(true);
+        t.start();
+    }
+
+    /**
+     * Stop the watch dog.
+     */
+    public synchronized void stop() {
+        stopped = true;
+        notifyAll();
+    }
+
+    /**
+     * The run method of the watch dog thread.
+     * This simply does a wait for the timeout time, and
+     * if the stop flag has not been set when the wait has returned or
+     * has been interrupted, the watch dog listeners are informed.
+     */
+    public synchronized void run() {
+        long now = System.currentTimeMillis();
+        final long until = now + timeout;
+
+        try {
+            while (!stopped && until > now) {
+                wait(until - now);
+                now = System.currentTimeMillis();
+            }
+        } catch (InterruptedException e) {
+            // Ignore exception
+        }
+        if (!stopped) {
+            fireTimeoutOccured();
+        }
+    }
+
+}