INT-1794 no longer creating a Message when a MessageSource returns a null payload object

spring-integration-core/src/main/java/org/springframework/integration/endpoint/AbstractMessageSource.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2010 the original author or authors.
+ * Copyright 2002-2011 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -30,6 +30,7 @@ import org.springframework.util.CollectionUtils;
 
 /**
  * @author Mark Fisher
+ * @author Oleg Zhurakousky
  * @since 2.0
  */
 public abstract class AbstractMessageSource<T> extends AbstractExpressionEvaluator implements MessageSource<T> {
@@ -46,9 +47,7 @@ public abstract class AbstractMessageSource<T> extends AbstractExpressionEvaluat
 	public final Message<T> receive() {
 		Message<T> message = null; 
 		Object result = this.doReceive();
-
 		Map<String, Object> headers = this.evaluateHeaders();
-		
 		if (result instanceof Message<?>) {
 			try {
 				message = (Message<T>) result;
@@ -63,7 +62,7 @@ public abstract class AbstractMessageSource<T> extends AbstractExpressionEvaluat
 				message = builder.build();
 			}
 		}
-		else {
+		else if (result != null) {
 			T payload = null;
 			try {
 				payload = (T) result;

spring-integration-core/src/test/java/org/springframework/integration/message/MethodInvokingMessageSourceTests.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2010 the original author or authors.
+ * Copyright 2002-2011 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -18,12 +18,12 @@ package org.springframework.integration.message;
 
 import static org.junit.Assert.assertEquals;
 import static org.junit.Assert.assertNotNull;
+import static org.junit.Assert.assertNull;
 
 import java.util.HashMap;
 import java.util.Map;
 
 import org.junit.Test;
-
 import org.springframework.expression.Expression;
 import org.springframework.expression.common.LiteralExpression;
 import org.springframework.expression.spel.standard.SpelExpressionParser;
@@ -88,6 +88,15 @@ public class MethodInvokingMessageSourceTests {
 		source.receive();
 	}
 
+	@Test
+	public void testNullReturningMethodReturnsNullMessage() {
+		MethodInvokingMessageSource source = new MethodInvokingMessageSource();
+		source.setObject(new TestBean());
+		source.setMethodName("nullReturningMethod");
+		Message<?> message = source.receive();
+		assertNull(message);
+	}
+
 
 	@SuppressWarnings("unused")
 	private static class TestBean {
@@ -102,6 +111,10 @@ public class MethodInvokingMessageSourceTests {
 
 		public void invalidMethodWithNoReturnValue() {
 		}
+
+		public Object nullReturningMethod() {
+			return null;
+		}
 	}
 
 }