[jboss-cvs] JBossAS SVN: r58105 - branches/JBoss_4_0_3_SP1_JBAS-3822/cluster/src/main/org/jboss/ha/framework/server

[jboss-cvs-commits at lists.jboss.org]

Author: bstansberry at jboss.com
Date: 2006-11-03 22:56:26 -0500 (Fri, 03 Nov 2006)
New Revision: 58105

Added:
   branches/JBoss_4_0_3_SP1_JBAS-3822/cluster/src/main/org/jboss/ha/framework/server/AsynchEventHandler.java
Log:
[JBAS-3822] Port HAPartition concurrency fixes to 4.0.3.SP1

Added: branches/JBoss_4_0_3_SP1_JBAS-3822/cluster/src/main/org/jboss/ha/framework/server/AsynchEventHandler.java
===================================================================
--- branches/JBoss_4_0_3_SP1_JBAS-3822/cluster/src/main/org/jboss/ha/framework/server/AsynchEventHandler.java	2006-11-04 03:55:53 UTC (rev 58104)
+++ branches/JBoss_4_0_3_SP1_JBAS-3822/cluster/src/main/org/jboss/ha/framework/server/AsynchEventHandler.java	2006-11-04 03:56:26 UTC (rev 58105)
@@ -0,0 +1,161 @@
+/*
+ * JBoss, Home of Professional Open Source.
+ * Copyright 2006, Red Hat Middleware LLC, and individual contributors
+ * as indicated by the @author tags. See the copyright.txt file in the
+ * distribution for a full listing of individual contributors.
+ *
+ * This is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU Lesser General Public License as
+ * published by the Free Software Foundation; either version 2.1 of
+ * the License, or (at your option) any later version.
+ *
+ * This software is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this software; if not, write to the Free
+ * Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
+ * 02110-1301 USA, or see the FSF site: http://www.fsf.org.
+ */
+package org.jboss.ha.framework.server;
+
+import org.jboss.logging.Logger;
+
+import EDU.oswego.cs.dl.util.concurrent.LinkedQueue;
+
+/**
+ * Utility class that accepts objects into a queue and maintains a separate
+ * thread that reads them off the queue and passes them to a registered
+ * "processor".
+ * 
+ * @todo find a better home for this than the cluster module
+ * 
+ * @author <a href="mailto://brian.stansberry@jboss.com">Brian Stansberry</a>
+ * @version $Revision$
+ */
+class AsynchEventHandler implements Runnable
+{
+   /**
+    * Interface implemented by classes able to process the objects
+    * placed into an AsynchEventHandler's queue.
+    */
+   public static interface AsynchEventProcessor
+   {
+      public void processEvent(Object event);
+   }
+   
+   private String name;
+   /** The LinkedQueue of events to pass to our processor */
+   private LinkedQueue events = new LinkedQueue();
+   /** Whether we're blocking on the queue */
+   private boolean blocking;
+   private AsynchEventProcessor processor;
+   private boolean stopped = true;
+   private Thread  handlerThread;
+   private Logger log;
+   
+   /**
+    * Create a new AsynchEventHandler.
+    * 
+    * @param processor  object to which objects placed in the queue should
+    *                   be handed when dequeued
+    * @param name       name for this instance.  Appended to the processor's
+    *                   class name to create a log category, and used
+    *                   to name to handler thread
+    */
+   public AsynchEventHandler(AsynchEventProcessor processor, String name)
+   {
+      super();
+      this.processor = processor;
+      if (name == null)
+         name = "AsynchEventHandler";
+      this.name = name;
+      this.log = Logger.getLogger(processor.getClass().getName() + "." + name);
+   }
+   
+   /**
+    * Place the given object in the queue.
+    * 
+    * @param event  the object to asynchronously pass to the 
+    *               AsynchEventHandler.
+    *               
+    * @throws InterruptedException  if the thread is interrupted while blocking
+    *                               on the queue.
+    */
+   public void queueEvent(Object event) throws InterruptedException
+   {
+      if (event != null)
+         events.put(event);
+   }
+   
+   public void run()
+   {
+      log.debug("Begin " + name + " Thread");
+      stopped = false;
+      while( !stopped )
+      {
+         try
+         {
+            blocking = true;
+            Object event = events.take();
+            blocking = false;
+            
+            if (!stopped) 
+            {
+               processor.processEvent(event);
+            }
+         }
+         catch(InterruptedException e)
+         {
+            blocking = false;
+            log.debug(name + " Thread interrupted", e);               
+            if (stopped)
+               break;
+         }
+         catch (Throwable t)
+         {
+            log.error("Caught Throwable handling asynch events", t);
+         }
+      }
+      log.debug("End " + name + " Thread");
+   }
+   
+   /**
+    * Starts the handler thread.
+    */
+   public void start()
+   {
+      handlerThread = new Thread(this, name + " Thread");
+      handlerThread.start();
+   }
+   
+   /**
+    * Stops the handler thread.
+    */
+   public void stop()
+   {
+      stopped = true;
+      if (blocking)
+         handlerThread.interrupt(); // it's just waiting on the LinkedQueue
+      
+      if (handlerThread.isAlive()) {
+         // Give it up to 100ms to finish whatever it's doing
+         try
+         {
+            handlerThread.join(100);
+         }
+         catch (Exception ignored) {}
+      }
+      
+      if (handlerThread.isAlive())
+         handlerThread.interrupt(); // kill it
+   }
+   
+   public boolean isStopped()
+   {
+      return stopped;
+   }
+
+}