From 166ab43c90a8f1c14872621e6fb4ae97d6c2a2f2 Mon Sep 17 00:00:00 2001 From: "Timothy A. Bish" Date: Wed, 19 Jun 2013 16:31:36 +0000 Subject: [PATCH] https://issues.apache.org/jira/browse/AMQ-4589 Apply patch to work around known race condition. git-svn-id: https://svn.apache.org/repos/asf/activemq/trunk@1494681 13f79535-47bb-0310-9956-ffa450edef68 --- .../org/apache/activemq/web/AjaxListener.java | 49 +++++++++---------- .../activemq/web/MessageListenerServlet.java | 9 ++-- 2 files changed, 28 insertions(+), 30 deletions(-) diff --git a/activemq-web/src/main/java/org/apache/activemq/web/AjaxListener.java b/activemq-web/src/main/java/org/apache/activemq/web/AjaxListener.java index ac0f093abf..df7d21ef3f 100644 --- a/activemq-web/src/main/java/org/apache/activemq/web/AjaxListener.java +++ b/activemq-web/src/main/java/org/apache/activemq/web/AjaxListener.java @@ -16,30 +16,27 @@ */ package org.apache.activemq.web; +import java.util.LinkedList; + import javax.jms.Message; import javax.jms.MessageConsumer; +import org.apache.activemq.MessageAvailableListener; import org.eclipse.jetty.continuation.Continuation; -import org.eclipse.jetty.continuation.ContinuationSupport; - import org.slf4j.Logger; import org.slf4j.LoggerFactory; -import org.apache.activemq.MessageAvailableListener; - -import java.util.LinkedList; - /* * Listen for available messages and wakeup any continuations. */ public class AjaxListener implements MessageAvailableListener { private static final Logger LOG = LoggerFactory.getLogger(AjaxListener.class); - - private long maximumReadTimeout; - private AjaxWebClient client; + + private final long maximumReadTimeout; + private final AjaxWebClient client; private long lastAccess; private Continuation continuation; - private LinkedList undeliveredMessages = new LinkedList(); + private final LinkedList undeliveredMessages = new LinkedList(); AjaxListener(AjaxWebClient client, long maximumReadTimeout) { this.client = client; @@ -58,7 +55,8 @@ public class AjaxListener implements MessageAvailableListener { public LinkedList getUndeliveredMessages() { return undeliveredMessages; } - + + @Override public synchronized void onMessageAvailable(MessageConsumer consumer) { if (LOG.isDebugEnabled()) { LOG.debug("message for " + consumer + " continuation=" + continuation); @@ -66,23 +64,24 @@ public class AjaxListener implements MessageAvailableListener { if (continuation != null) { try { Message message = consumer.receive(10); - LOG.debug( "message is " + message ); - if( message != null ) { - if( continuation.isSuspended() ) { - LOG.debug( "Resuming suspended continuation " + continuation ); - continuation.setAttribute("undelivered_message", new UndeliveredAjaxMessage( message, consumer ) ); + LOG.debug("message is " + message); + if (message != null) { + if (!continuation.isResumed()) { + LOG.debug("Resuming suspended continuation " + continuation); + continuation.setAttribute("undelivered_message", new UndeliveredAjaxMessage(message, consumer)); continuation.resume(); } else { - LOG.debug( "Message available, but continuation is already resumed. Buffer for next time." ); - bufferMessageForDelivery( message, consumer ); + LOG.debug("Message available, but continuation is already resumed. Buffer for next time."); + bufferMessageForDelivery(message, consumer); } } } catch (Exception e) { LOG.error("Error receiving message " + e, e); } - + } else if (System.currentTimeMillis() - lastAccess > 2 * this.maximumReadTimeout) { new Thread() { + @Override public void run() { client.closeConsumers(); }; @@ -90,17 +89,17 @@ public class AjaxListener implements MessageAvailableListener { } else { try { Message message = consumer.receive(10); - bufferMessageForDelivery( message, consumer ); + bufferMessageForDelivery(message, consumer); } catch (Exception e) { LOG.error("Error receiving message " + e, e); } } } - - public void bufferMessageForDelivery( Message message, MessageConsumer consumer ) { - if( message != null ) { - synchronized( undeliveredMessages ) { - undeliveredMessages.addLast( new UndeliveredAjaxMessage( message, consumer ) ); + + public void bufferMessageForDelivery(Message message, MessageConsumer consumer) { + if (message != null) { + synchronized (undeliveredMessages) { + undeliveredMessages.addLast(new UndeliveredAjaxMessage(message, consumer)); } } } diff --git a/activemq-web/src/main/java/org/apache/activemq/web/MessageListenerServlet.java b/activemq-web/src/main/java/org/apache/activemq/web/MessageListenerServlet.java index 33b7473634..cb4cc3c822 100644 --- a/activemq-web/src/main/java/org/apache/activemq/web/MessageListenerServlet.java +++ b/activemq-web/src/main/java/org/apache/activemq/web/MessageListenerServlet.java @@ -313,20 +313,20 @@ public class MessageListenerServlet extends MessageServletSupport { Continuation continuation = ContinuationSupport.getContinuation(request); // Add a listener to the continuation to make sure it actually - // will expire (seems like a bug in Jetty Servlet 3 continuations, + // will expire (seems like a bug in Jetty Servlet 3 continuations, // see https://issues.apache.org/jira/browse/AMQ-3447 continuation.addContinuationListener(new ContinuationListener() { @Override public void onTimeout(Continuation cont) { if (LOG.isDebugEnabled()) { - LOG.debug("Continuation " + cont.toString() + " expired."); + LOG.debug("Continuation " + cont.toString() + " expired."); } } @Override public void onComplete(Continuation cont) { if (LOG.isDebugEnabled()) { - LOG.debug("Continuation " + cont.toString() + " completed."); + LOG.debug("Continuation " + cont.toString() + " completed."); } } }); @@ -381,7 +381,7 @@ public class MessageListenerServlet extends MessageServletSupport { LinkedList undeliveredMessages = ((AjaxListener)consumer.getAvailableListener()).getUndeliveredMessages(); LOG.debug("Send " + undeliveredMessages.size() + " unconsumed messages"); synchronized( undeliveredMessages ) { - for (Iterator it = undeliveredMessages.iterator(); it.hasNext(); ) { + for (Iterator it = undeliveredMessages.iterator(); it.hasNext();) { messages++; UndeliveredAjaxMessage undelivered = it.next(); Message msg = undelivered.getMessage(); @@ -425,7 +425,6 @@ public class MessageListenerServlet extends MessageServletSupport { String m = swriter.toString(); response.getWriter().println(m); } - } protected void writeMessageResponse(PrintWriter writer, Message message, String id, String destinationName) throws JMSException, IOException {