refactor ExecuteWatchdog - extract a more generic timer. Preparation

to allow timeout attribute in <java fork="false">


git-svn-id: https://svn.apache.org/repos/asf/ant/core/trunk@272235 13f79535-47bb-0310-9956-ffa450edef68

src/main/org/apache/tools/ant/taskdefs/ExecuteWatchdog.java

@@ -1,7 +1,7 @@
 /*
  * The Apache Software License, Version 1.1
  *
- * Copyright (c) 2000-2001 The Apache Software Foundation.  All rights
+ * Copyright (c) 2000-2002 The Apache Software Foundation.  All rights
  * reserved.
  *
  * Redistribution and use in source and binary forms, with or without
@@ -55,6 +55,8 @@
 package org.apache.tools.ant.taskdefs;
 
 import org.apache.tools.ant.BuildException;
+import org.apache.tools.ant.util.TimeoutObserver;
+import org.apache.tools.ant.util.Watchdog;
 
 /**
  * Destroys a process running for too long.
@@ -72,15 +74,13 @@ import org.apache.tools.ant.BuildException;
  * @author thomas.haas@softwired-inc.com
  * @author <a href="mailto:sbailliez@imediation.com">Stephane Bailliez</a>
  * @see Execute
+ * @see org.apache.tools.ant.util.Watchdog
  */
-public class ExecuteWatchdog implements Runnable {
+public class ExecuteWatchdog implements TimeoutObserver {
         
     /** the process to execute and watch for duration */
     private Process process;
 
-    /** timeout duration. Once the process running time exceeds this it should be killed */
-    private int timeout;
-
     /** say whether or not the watchog is currently monitoring a process */
     private boolean watch = false;
         
@@ -90,16 +90,17 @@ public class ExecuteWatchdog implements Runnable {
     /** say whether or not the process was killed due to running overtime */
     private boolean     killedProcess = false;
 
+    /** will tell us whether timeout has occured */
+    private Watchdog watchdog;
+
     /**
      * Creates a new watchdog with a given timeout.
      *
      * @param timeout the timeout for the process in milliseconds. It must be greather than 0.
      */
     public ExecuteWatchdog(int timeout) {
-        if (timeout < 1) {
-            throw new IllegalArgumentException("timeout lesser than 1.");
-        }
-        this.timeout = timeout;
+        watchdog = new Watchdog(timeout);
+        watchdog.addTimeoutObserver(this);
     }
 
     /**
@@ -119,43 +120,28 @@ public class ExecuteWatchdog implements Runnable {
         this.killedProcess = false;
         this.watch = true;
         this.process = process;
-        final Thread thread = new Thread(this, "WATCHDOG");
-        thread.setDaemon(true);
-        thread.start();
+        watchdog.start();
     }
 
     /**
      * Stops the watcher. It will notify all threads possibly waiting on this object.
      */
     public synchronized void stop() {
+        watchdog.stop();
         watch = false;
-        notifyAll();
+        process = null;
     }
 
-
     /**
-     * Watches the process and terminates it, if it runs for to long.
+     * Called after watchdog has finished.
      */
-    public synchronized void run() {
+    public void timeoutOccured(Watchdog w) {
         try {
-            // This isn't a Task, don't have a Project object to log.
-            // project.log("ExecuteWatchdog: timeout = "+timeout+" msec",  Project.MSG_VERBOSE);
-            final long until = System.currentTimeMillis() + timeout;
-            long now;
-            while (watch && until > (now = System.currentTimeMillis())) {
-                try {
-                    wait(until - now);
-                } catch (InterruptedException e) {}
-            }
-
-            // if we are here, either someone stopped the watchdog,
-            // we are on timeout and the process must be killed, or
-            // we are on timeout and the process has already stopped.
             try {
                 // We must check if the process was not stopped
                 // before being here
                 process.exitValue();
-            } catch (IllegalThreadStateException e){
+            } catch (IllegalThreadStateException itse){
                 // the process is not terminated, if this is really
                 // a timeout and not a manual stop then kill it.
                 if (watch){
@@ -163,7 +149,7 @@ public class ExecuteWatchdog implements Runnable {
                     process.destroy();
                 }
             }
-        } catch(Exception e) {
+        } catch (Exception e) {
             caught = e;
         } finally {
             cleanUp();

src/main/org/apache/tools/ant/util/TimeoutObserver.java

@@ -0,0 +1,70 @@
+/*
+ * The Apache Software License, Version 1.1
+ *
+ * Copyright (c) 2002 The Apache Software Foundation.  All rights
+ * reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ *
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in
+ *    the documentation and/or other materials provided with the
+ *    distribution.
+ *
+ * 3. The end-user documentation included with the redistribution, if
+ *    any, must include the following acknowlegement:
+ *       "This product includes software developed by the
+ *        Apache Software Foundation (http://www.apache.org/)."
+ *    Alternately, this acknowlegement may appear in the software itself,
+ *    if and wherever such third-party acknowlegements normally appear.
+ *
+ * 4. The names "The Jakarta Project", "Ant", and "Apache Software
+ *    Foundation" must not be used to endorse or promote products derived
+ *    from this software without prior written permission. For written
+ *    permission, please contact apache@apache.org.
+ *
+ * 5. Products derived from this software may not be called "Apache"
+ *    nor may "Apache" appear in their names without prior written
+ *    permission of the Apache Group.
+ *
+ * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED
+ * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
+ * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+ * DISCLAIMED.  IN NO EVENT SHALL THE APACHE SOFTWARE FOUNDATION OR
+ * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+ * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
+ * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
+ * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
+ * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
+ * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ * ====================================================================
+ *
+ * This software consists of voluntary contributions made by many
+ * individuals on behalf of the Apache Software Foundation.  For more
+ * information on the Apache Software Foundation, please see
+ * <http://www.apache.org/>.
+ */
+
+package org.apache.tools.ant.util;
+
+/**
+ * Interface for classes that want to be notified by Watchdog.
+ *
+ * @since 1.5
+ *
+ * @see org.apache.tools.ant.util.Watchdog
+ *
+ * @author <a href="stefan.bodewig@epost.de">Stefan Bodewig</a>
+ */
+public interface TimeoutObserver {
+
+    void timeoutOccured(Watchdog w);
+
+}

src/main/org/apache/tools/ant/util/Watchdog.java

@@ -0,0 +1,124 @@
+/*
+ * The Apache Software License, Version 1.1
+ *
+ * Copyright (c) 2002 The Apache Software Foundation.  All rights
+ * reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ *
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in
+ *    the documentation and/or other materials provided with the
+ *    distribution.
+ *
+ * 3. The end-user documentation included with the redistribution, if
+ *    any, must include the following acknowlegement:
+ *       "This product includes software developed by the
+ *        Apache Software Foundation (http://www.apache.org/)."
+ *    Alternately, this acknowlegement may appear in the software itself,
+ *    if and wherever such third-party acknowlegements normally appear.
+ *
+ * 4. The names "The Jakarta Project", "Ant", and "Apache Software
+ *    Foundation" must not be used to endorse or promote products derived
+ *    from this software without prior written permission. For written
+ *    permission, please contact apache@apache.org.
+ *
+ * 5. Products derived from this software may not be called "Apache"
+ *    nor may "Apache" appear in their names without prior written
+ *    permission of the Apache Group.
+ *
+ * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED
+ * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
+ * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+ * DISCLAIMED.  IN NO EVENT SHALL THE APACHE SOFTWARE FOUNDATION OR
+ * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+ * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
+ * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
+ * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
+ * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
+ * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ * ====================================================================
+ *
+ * This software consists of voluntary contributions made by many
+ * individuals on behalf of the Apache Software Foundation.  For more
+ * information on the Apache Software Foundation, please see
+ * <http://www.apache.org/>.
+ */
+
+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
+ *
+ * @author <a href="stefan.bodewig@epost.de">Stefan Bodewig</a>
+ * @author thomas.haas@softwired-inc.com
+ * @author <a href="mailto:sbailliez@imediation.com">Stephane Bailliez</a>
+ */
+public class Watchdog implements Runnable {
+
+    private Vector observers = new Vector(1);
+    private long timeout = -1;
+    private boolean stopped = false;
+
+    public Watchdog(long timeout) {
+        if (timeout < 1) {
+            throw new IllegalArgumentException("timeout lesser than 1.");
+        }
+        this.timeout = timeout;
+    }
+
+    public void addTimeoutObserver(TimeoutObserver to) {
+        observers.addElement(to);
+    }
+
+    public void removeTimeoutObserver(TimeoutObserver to) {
+        observers.removeElement(to);
+    }
+
+    protected final void fireTimeoutOccured() {
+        Enumeration enum = observers.elements();
+        while (enum.hasMoreElements()) {
+            ((TimeoutObserver) enum.nextElement()).timeoutOccured(this);
+        }
+    }
+
+    public synchronized void start() {
+        stopped = false;
+        Thread t = new Thread(this, "WATCHDOG");
+        t.setDaemon(true);
+        t.start();
+    }
+
+    public synchronized void stop() {
+        stopped = true;
+        notifyAll();
+    }
+
+    public synchronized void run() {
+        final long until = System.currentTimeMillis() + timeout;
+        long now;
+        while (!stopped && until > (now = System.currentTimeMillis())) {
+            try {
+                    wait(until - now);
+            } catch (InterruptedException e) {}
+        }
+        if (!stopped) {
+            fireTimeoutOccured();
+        }
+    }
+
+}