IN PROGRESS - issue INT-574: Chain element should support aggregators mid chain as well as handlers extending AbstractReplyProducingMessageHandler

http://jira.springframework.org/browse/INT-574

Updated the xsd to allow aggregator (and nested <chain/>)

org.springframework.integration/src/test/java/org/springframework/integration/config/ChainParserTests-context.xml

@@ -45,6 +45,13 @@
 			class="org.springframework.integration.config.ChainParserTests$StubHandler" />
 	</chain>
 
+	<chain input-channel="aggregatorInput" output-channel="output">
+		<aggregator ref="aggregatorBean" method="aggregate" />
+	</chain>
+
+	<beans:bean id="aggregatorBean"
+		class="org.springframework.integration.config.ChainParserTests$StubAggregator" />
+
 	<beans:bean id="testHeaderValue" class="java.lang.Integer">
 		<beans:constructor-arg value="123" />
 	</beans:bean>

org.springframework.integration/src/test/java/org/springframework/integration/config/ChainParserTests.java

@@ -22,6 +22,8 @@ import static org.junit.Assert.assertNotNull;
 import static org.junit.Assert.assertNull;
 import static org.junit.Assert.assertThat;
 
+import java.util.List;
+
 import org.junit.Test;
 import org.junit.runner.RunWith;
 
@@ -35,6 +37,7 @@ import org.springframework.integration.handler.ReplyMessageHolder;
 import org.springframework.integration.message.MessageBuilder;
 import org.springframework.test.context.ContextConfiguration;
 import org.springframework.test.context.junit4.SpringJUnit4ClassRunner;
+import org.springframework.util.StringUtils;
 
 /**
  * @author Mark Fisher
@@ -127,5 +130,10 @@ public class ChainParserTests  {
 		}
 		
 	}
-
+	
+	public static class StubAggregator {
+		public String aggregate(List<String> strings){
+			return StringUtils.collectionToCommaDelimitedString(strings);
+		}
+	}
 }