From db75fcb34ed8d469fe7ff1a0e7afddf4a1d89177 Mon Sep 17 00:00:00 2001 From: Conor MacNeill Date: Fri, 25 Jul 2003 11:02:53 +0000 Subject: [PATCH] Add element to to start threads which continue to run after the task has completed. git-svn-id: https://svn.apache.org/repos/asf/ant/core/trunk@274950 13f79535-47bb-0310-9956-ffa450edef68 --- WHATSNEW | 12 +- docs/manual/CoreTasks/parallel.html | 19 ++ .../apache/tools/ant/taskdefs/Parallel.java | 166 ++++++++++++------ 3 files changed, 143 insertions(+), 54 deletions(-) diff --git a/WHATSNEW b/WHATSNEW index e2136c4f0..034167a6f 100644 --- a/WHATSNEW +++ b/WHATSNEW @@ -499,7 +499,7 @@ Other changes: * OpenVMS is detected as a valid OS family. -* DirectoryScanner has been optimized for cases where include patterns do not +* DirectoryScanner has been optimized for cases where include patterns do not start with wildcards. Bugzilla Report 20103. * Added keep-going feature. Bugzilla Report 21144 @@ -514,7 +514,15 @@ Other changes: an enablemultiplemapping attribute. Bugzilla Report 21320. * will now work on OpenVMS (please read the notes in - 's manual page). Bugzilla Report 21877. + 's manual page). Bugzilla Report 21877. + +* now supports a timeout which can be used to recover + from deadlocks, etc in the parallel threads. also + now supports a nested element. This can be used to + run tasks in daemon threads which the parallel task will not + wait for before completing. A new attribute failonany will cause + to throw an exception if any thread fails without + waiting for all other threads to complete. Changes from Ant 1.5.2 to Ant 1.5.3 =================================== diff --git a/docs/manual/CoreTasks/parallel.html b/docs/manual/CoreTasks/parallel.html index 35e48843b..3a0db8209 100644 --- a/docs/manual/CoreTasks/parallel.html +++ b/docs/manual/CoreTasks/parallel.html @@ -99,6 +99,25 @@ taking up all available threads before the tasks that would unlock the waitfor would occur. This is not a repalcement for Java Language level thread semantics and is best used for "embarassingly parallel" tasks.

+ +

Parameters specified as nested elements

+ +

daemons

+

+The parallel task supports a <daemons> nested element. This is a list of tasks +which are to be run in parallel daemon threads. The parallel task will not wait for +these tasks to complete. Being daemon threads, however, they will not prevent Ant from +completing, whereupon the threads are terminated. Failures in daemon threads which +occur before the parallel task itself finishes will be reported and can cause +parallel to throw an exception. Failures which occur after parallel has completed are not +reported. +

+ +

Daemon tasks can be used, for example, to start test servers which might not be easily +terminated from Ant. By using <daemons> such servers do not halt the build. +

+ +

Examples

 <parallel>
diff --git a/src/main/org/apache/tools/ant/taskdefs/Parallel.java b/src/main/org/apache/tools/ant/taskdefs/Parallel.java
index cc4b86d0d..cd3d8dc22 100644
--- a/src/main/org/apache/tools/ant/taskdefs/Parallel.java
+++ b/src/main/org/apache/tools/ant/taskdefs/Parallel.java
@@ -56,6 +56,8 @@ package org.apache.tools.ant.taskdefs;
 import java.lang.reflect.Method;
 import java.util.Enumeration;
 import java.util.Vector;
+import java.util.List;
+import java.util.ArrayList;
 import org.apache.tools.ant.BuildException;
 import org.apache.tools.ant.Location;
 import org.apache.tools.ant.Task;
@@ -86,6 +88,21 @@ import org.apache.tools.ant.util.StringUtils;
 public class Parallel extends Task
                       implements TaskContainer {
 
+    /** Class which holds a list of tasks to execute */
+    public static class TaskList implements TaskContainer {
+        /** Collection holding the nested tasks */
+        private List tasks = new ArrayList();
+
+        /**
+         * Add a nested task to execute parallel (asynchron).
+         * 

+         * @param nestedTask  Nested task to be executed in parallel
+         */
+        public void addTask(Task nestedTask) throws BuildException {
+            tasks.add(nestedTask);
+        }
+    }
+
     /** Collection holding the nested tasks */
     private Vector nestedTasks = new Vector();
 
@@ -98,12 +115,13 @@ public class Parallel extends Task
     /** Total number of threads per processor to run.  */
     private int numThreadsPerProcessor = 0;
 
+    /** The timeout period in milliseconds */
     private long timeout;
 
     /** Indicates threads are still running and new threads can be issued */
     private volatile boolean stillRunning;
 
-    /** INdicates that the execution timedout */
+    /** Indicates that the execution timedout */
     private boolean timedOut;
 
     /**
@@ -112,6 +130,31 @@ public class Parallel extends Task
      */
     private boolean failOnAny;
 
+    /** The dameon task list if any */
+    private TaskList daemonTasks;
+
+    /** Accumulation of exceptions messages from all nested tasks */
+    private StringBuffer exceptionMessage;
+
+    /** Number of exceptions from nested tasks */
+    private int numExceptions = 0;
+
+    /** The first exception encountered */
+    private Throwable firstException;
+
+    /** The location of the first exception */
+    private Location firstLocation;
+
+    /**
+     * Add a group of daemon threads
+     */
+    public void addDaemons(TaskList daemonTasks) {
+        if (this.daemonTasks != null) {
+            throw new BuildException("Only one daemon group is supported");
+        }
+        this.daemonTasks = daemonTasks;
+    }
+
     /**
      * Interval to poll for completed threads when threadCount or
      * threadsPerProcessor is specified.  Integer in milliseconds.; optional
@@ -211,6 +254,27 @@ public class Parallel extends Task
         }
     }
 
+    private void processExceptions(TaskRunnable[] runnables) {
+        if (runnables == null) {
+            return;
+        }
+        for (int i = 0; i < runnables.length; ++i) {
+            Throwable t = runnables[i].getException();
+            if (t != null) {
+                numExceptions++;
+                if (firstException == null) {
+                    firstException = t;
+                }
+                if (t instanceof BuildException
+                    && firstLocation == Location.UNKNOWN_LOCATION) {
+                    firstLocation = ((BuildException) t).getLocation();
+                }
+                exceptionMessage.append(StringUtils.LINE_SEP);
+                exceptionMessage.append(t.getMessage());
+            }
+        }
+    }
+
     /**
      * Spin up required threads with a maximum number active at any given time.
      *
@@ -227,7 +291,7 @@ public class Parallel extends Task
              threadNumber++) {
             Task nestedTask = (Task) e.nextElement();
             runnables[threadNumber]
-                = new TaskRunnable(threadNumber, nestedTask);
+                = new TaskRunnable(nestedTask);
         }
 
         final int maxRunning = numTasks < numThreads ? numTasks : numThreads;
@@ -236,37 +300,52 @@ public class Parallel extends Task
         threadNumber = 0;
         ThreadGroup group = new ThreadGroup("parallel");
 
-        // now run them in limited numbers...
-        // start initial batch of threads
-        for (int i = 0; i < maxRunning; ++i) {
-            running[i] = runnables[threadNumber++];
-            Thread thread =  new Thread(group, running[i]);
-            thread.start();
+        TaskRunnable[] daemons = null;
+        if (daemonTasks != null && daemonTasks.tasks.size() != 0) {
+            daemons = new TaskRunnable[daemonTasks.tasks.size()];
         }
 
-        if (timeout != 0) {
-            // start the timeout thread
-            Thread timeoutThread = new Thread() {
-                public synchronized void run() {
-                    try {
-                        wait(timeout);
-                        synchronized (semaphore) {
-                            stillRunning = false;
-                            timedOut = true;
-                            semaphore.notifyAll();
+        synchronized (semaphore) {
+            // start any daemon threads
+            if (daemons != null) {
+                for (int i = 0; i < daemons.length; ++i) {
+                    daemons[i] = new TaskRunnable((Task) daemonTasks.tasks.get(i));
+                    Thread daemonThread =  new Thread(group, daemons[i]);
+                    daemonThread.setDaemon(true);
+                    daemonThread.start();
+                }
+            }
+
+            // now run main threads in limited numbers...
+            // start initial batch of threads
+            for (int i = 0; i < maxRunning; ++i) {
+                running[i] = runnables[threadNumber++];
+                Thread thread =  new Thread(group, running[i]);
+                thread.start();
+            }
+
+            if (timeout != 0) {
+                // start the timeout thread
+                Thread timeoutThread = new Thread() {
+                    public synchronized void run() {
+                        try {
+                            wait(timeout);
+                            synchronized (semaphore) {
+                                stillRunning = false;
+                                timedOut = true;
+                                semaphore.notifyAll();
+                            }
+                        } catch (InterruptedException e) {
+                            // ignore
                         }
-                    } catch (InterruptedException e) {
-                        // ignore
                     }
-                }
-            };
-            timeoutThread.start();
-        }
+                };
+                timeoutThread.start();
+            }
 
-        // now find available running slots for the remaining threads
-        outer:
-        while (threadNumber < numTasks && stillRunning) {
-            synchronized (semaphore) {
+            // now find available running slots for the remaining threads
+            outer:
+            while (threadNumber < numTasks && stillRunning) {
                 for (int i = 0; i < maxRunning; i++) {
                     if (running[i] == null || running[i].finished) {
                         running[i] = runnables[threadNumber++];
@@ -288,9 +367,7 @@ public class Parallel extends Task
                     // sheesh!
                 }
             }
-        }
 
-        synchronized (semaphore) {
             // are all threads finished
             outer2:
             while (stillRunning) {
@@ -315,25 +392,12 @@ public class Parallel extends Task
         }
 
         // now did any of the threads throw an exception
-        StringBuffer exceptionMessage = new StringBuffer();
-        int numExceptions = 0;
-        Throwable firstException = null;
-        Location firstLocation = Location.UNKNOWN_LOCATION;
-        for (int i = 0; i < numTasks; ++i) {
-            Throwable t = runnables[i].getException();
-            if (t != null) {
-                numExceptions++;
-                if (firstException == null) {
-                    firstException = t;
-                }
-                if (t instanceof BuildException
-                    && firstLocation == Location.UNKNOWN_LOCATION) {
-                    firstLocation = ((BuildException) t).getLocation();
-                }
-                exceptionMessage.append(StringUtils.LINE_SEP);
-                exceptionMessage.append(t.getMessage());
-            }
-        }
+        exceptionMessage = new StringBuffer();
+        numExceptions = 0;
+        firstException = null;
+        firstLocation = Location.UNKNOWN_LOCATION;
+        processExceptions(daemons);
+        processExceptions(runnables);
 
         if (numExceptions == 1) {
             if (firstException instanceof BuildException) {
@@ -373,7 +437,6 @@ public class Parallel extends Task
     private class TaskRunnable implements Runnable {
         private Throwable exception;
         private Task task;
-        private int taskNumber;
         boolean finished;
 
         /**
@@ -381,9 +444,8 @@ public class Parallel extends Task
          *
          * @param task the Task to be executed in a seperate thread
          */
-        TaskRunnable(int taskNumber, Task task) {
+        TaskRunnable(Task task) {
             this.task = task;
-            this.taskNumber = taskNumber;
         }
 
         /**