From 5b18ceda1670947eebb26485195dd30d5f239473 Mon Sep 17 00:00:00 2001
From: Robert Godfrey <rgodfrey@apache.org>
Date: Wed, 16 Apr 2008 09:56:48 +0000
Subject: QPID-927 : Multiple acknowledgements should be coalesced into single
 multiple ack

git-svn-id: https://svn.apache.org/repos/asf/incubator/qpid/branches/M2.1@648652 13f79535-47bb-0310-9956-ffa450edef68
---
 .../apache/qpid/client/BasicMessageConsumer.java   | 63 +++++++++++++++++++++-
 1 file changed, 61 insertions(+), 2 deletions(-)

diff --git a/java/client/src/main/java/org/apache/qpid/client/BasicMessageConsumer.java b/java/client/src/main/java/org/apache/qpid/client/BasicMessageConsumer.java
index efbce6033b..4d993eafa3 100644
--- a/java/client/src/main/java/org/apache/qpid/client/BasicMessageConsumer.java
+++ b/java/client/src/main/java/org/apache/qpid/client/BasicMessageConsumer.java
@@ -39,6 +39,10 @@ import java.util.Arrays;
 import java.util.Iterator;
 import java.util.List;
 import java.util.Map;
+import java.util.SortedSet;
+import java.util.ArrayList;
+import java.util.Collections;
+import java.util.TreeSet;
 import java.util.concurrent.ArrayBlockingQueue;
 import java.util.concurrent.ConcurrentLinkedQueue;
 import java.util.concurrent.TimeUnit;
@@ -111,6 +115,14 @@ public class BasicMessageConsumer extends Closeable implements MessageConsumer
     /** List of tags delievered, The last of which which should be acknowledged on commit in transaction mode. */
     private ConcurrentLinkedQueue<Long> _receivedDeliveryTags = new ConcurrentLinkedQueue<Long>();
 
+    /** The last tag that was "multiple" acknowledged on this session (if transacted) */
+    private long _lastAcked;
+
+    /** set of tags which have previously been acked; but not part of the multiple ack (transacted mode only) */
+    private final SortedSet<Long> _previouslyAcked = new TreeSet<Long>();
+
+    private final Object _commitLock = new Object();
+
     /**
      * The thread that was used to call receive(). This is important for being able to interrupt that thread if a
      * receive() is in progress.
@@ -126,6 +138,8 @@ public class BasicMessageConsumer extends Closeable implements MessageConsumer
     private final boolean _noConsume;
     private List<StackTraceElement> _closedStack = null;
 
+
+
     protected BasicMessageConsumer(int channelId, AMQConnection connection, AMQDestination destination,
                                    String messageSelector, boolean noLocal, MessageFactoryRegistry messageFactory, AMQSession session,
                                    AMQProtocolHandler protocolHandler, FieldTable rawSelectorFieldTable, int prefetchHigh, int prefetchLow,
@@ -809,9 +823,54 @@ public class BasicMessageConsumer extends Closeable implements MessageConsumer
     /** Acknowledge up to last message delivered (if any). Used when commiting. */
     void acknowledgeDelivered()
     {
-    	while (!_receivedDeliveryTags.isEmpty())
+        synchronized(_commitLock)
         {
-    		_session.acknowledgeMessage(_receivedDeliveryTags.poll(), false);
+            ArrayList<Long> tagsToAck = new ArrayList<Long>();
+
+            while (!_receivedDeliveryTags.isEmpty())
+            {
+                tagsToAck.add(_receivedDeliveryTags.poll());
+            }
+
+            Collections.sort(tagsToAck);
+
+            long prevAcked = _lastAcked;
+            long oldAckPoint = -1;
+
+            while(oldAckPoint != prevAcked)
+            {
+                oldAckPoint = prevAcked;
+
+                Iterator<Long> tagsToAckIterator = tagsToAck.iterator();
+
+                while(tagsToAckIterator.hasNext() && tagsToAckIterator.next() == prevAcked+1)
+                {
+                    tagsToAckIterator.remove();
+                    prevAcked++;
+                }
+
+                Iterator<Long> previousAckIterator = _previouslyAcked.iterator();
+                while(previousAckIterator.hasNext() && previousAckIterator.next() == prevAcked+1)
+                {
+                    previousAckIterator.remove();
+                    prevAcked++;
+                }
+
+            }
+            if(prevAcked != _lastAcked)
+            {
+                _session.acknowledgeMessage(prevAcked, true);
+                _lastAcked = prevAcked;
+            }
+
+            Iterator<Long> tagsToAckIterator = tagsToAck.iterator();
+
+            while(tagsToAckIterator.hasNext())
+            {
+                Long tag = tagsToAckIterator.next();
+                _session.acknowledgeMessage(tag, false);
+                _previouslyAcked.add(tag);
+            }
         }
     }
 
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