INT-1093:

- Added testcases from the issue
- added convenience method for total completion to MessageGroup
- resolved issue by invoking callback

org.springframework.integration/src/main/java/org/springframework/integration/aggregator/AbstractAggregatingMessageGroupProcessor.java

@@ -16,15 +16,8 @@
 
 package org.springframework.integration.aggregator;
 
-import java.util.HashMap;
-import java.util.HashSet;
-import java.util.List;
-import java.util.Map;
-import java.util.Set;
-
 import org.apache.commons.logging.Log;
 import org.apache.commons.logging.LogFactory;
-
 import org.springframework.integration.channel.MessageChannelTemplate;
 import org.springframework.integration.core.Message;
 import org.springframework.integration.core.MessageChannel;
@@ -32,6 +25,8 @@ import org.springframework.integration.core.MessageHeaders;
 import org.springframework.integration.message.MessageBuilder;
 import org.springframework.util.Assert;
 
+import java.util.*;
+
 /**
  * Base class for MessageGroupProcessor implementations that aggregate the
  * group of Messages into a single Message.
@@ -53,6 +48,7 @@ public abstract class AbstractAggregatingMessageGroupProcessor implements Messag
 		Map<String, Object> headers = this.aggregateHeaders(group);
 		Message<?> message = MessageBuilder.withPayload(payload).copyHeadersIfAbsent(headers).build();
 		channelTemplate.send(message, outputChannel);
+		group.onCompleteProcessing();
 	}
 
 	/**

org.springframework.integration/src/main/java/org/springframework/integration/aggregator/MessageGroup.java

@@ -16,14 +16,10 @@
 
 package org.springframework.integration.aggregator;
 
-import java.util.ArrayList;
-import java.util.Arrays;
-import java.util.Collection;
-import java.util.Collections;
-import java.util.List;
-
 import org.springframework.integration.core.Message;
 
+import java.util.*;
+
 /**
  * Represents a mutable group of correlated messages that is bound to a certain
  * {@link org.springframework.integration.store.MessageStore} and correlation
@@ -128,4 +124,13 @@ public class MessageGroup {
 		}
 	}
 
+	/**
+	 * This method is a shorthand for signaling that all messages in the group have been
+	 * processed and that the group is completed.
+	 */
+	public void onCompleteProcessing() {
+		onProcessingOf(messages.toArray(new Message[messages.size()]));
+		onCompletion();
+    }
+
 }