INT-682, added no-arg method support for handlers, removed assertion for no-arg handler methods in HandlerMethodUtils and StaticHandlerMethodResolver, fixed test cases

org.springframework.integration/src/main/java/org/springframework/integration/handler/HandlerMethodUtils.java

@@ -30,6 +30,7 @@ import org.springframework.integration.annotation.Headers;
  * Utility methods for common behavior related to Message-handling methods.
  * 
  * @author Mark Fisher
+ * @author Oleg Zhurakousky
  */
 abstract class HandlerMethodUtils {
 
@@ -47,9 +48,6 @@ abstract class HandlerMethodUtils {
 			return false;
 		}
 		Class<?>[] parameterTypes = method.getParameterTypes();
-		if (parameterTypes.length == 0) {
-			return false;
-		}
 		if (parameterTypes.length > 1) {
 			// at most one parameter can be lacking @Header or @Headers
 			boolean foundPayloadParam = false;

org.springframework.integration/src/main/java/org/springframework/integration/handler/StaticHandlerMethodResolver.java

@@ -27,6 +27,7 @@ import org.springframework.util.Assert;
  * or otherwise resolvable in advance based on static metadata.
  * 
  * @author Mark Fisher
+ * @author Oleg Zhurakousky
  */
 public class StaticHandlerMethodResolver implements HandlerMethodResolver {
 
@@ -35,8 +36,6 @@ public class StaticHandlerMethodResolver implements HandlerMethodResolver {
 
 	public StaticHandlerMethodResolver(Method method) {
 		Assert.notNull(method, "method must not be null");
-		Assert.notEmpty(method.getParameterTypes(),
-				"Message-handling method [" + method + "] must accept at least one parameter.");
 		Assert.isTrue(HandlerMethodUtils.isValidHandlerMethod(method),
 				"Invalid Message-handling method [" + method + "]");
 		this.method = method;

org.springframework.integration/src/test/java/org/springframework/integration/filter/MethodInvokingSelectorTests.java

@@ -29,6 +29,7 @@ import org.springframework.integration.message.StringMessage;
 
 /**
  * @author Mark Fisher
+ * @author Oleg Zhurakousky
  */
 public class MethodInvokingSelectorTests {
 
@@ -60,13 +61,13 @@ public class MethodInvokingSelectorTests {
 		assertFalse(selector.accept(new GenericMessage<Integer>(99)));
 	}
 
-	@Test(expected = IllegalArgumentException.class)
+	@Test
 	public void noArgMethodWithMethodName() {
 		MethodInvokingSelector selector = new MethodInvokingSelector(new TestBean(), "noArgs");
 		selector.accept(new StringMessage("test"));
 	}
 
-	@Test(expected = IllegalArgumentException.class)
+	@Test
 	public void noArgMethodWithMethodReference() throws Exception {
 		TestBean testBean = new TestBean();
 		Method method = testBean.getClass().getMethod("noArgs", new Class[] {});

org.springframework.integration/src/test/java/org/springframework/integration/handler/StaticHandlerMethodResolverTests.java

@@ -28,6 +28,7 @@ import org.springframework.integration.message.StringMessage;
 
 /**
  * @author Mark Fisher
+ * @author Oleg Zhurakousky
  */
 public class StaticHandlerMethodResolverTests {
 
@@ -37,7 +38,7 @@ public class StaticHandlerMethodResolverTests {
 		new StaticHandlerMethodResolver(method);
 	}
 
-	@Test(expected = IllegalArgumentException.class)
+	@Test
 	public void noArgMethodIsNotValid() throws Exception {
 		Method method = TestBean.class.getDeclaredMethod("noArgMethod", new Class<?>[0]);
 		new StaticHandlerMethodResolver(method);

org.springframework.integration/src/test/java/org/springframework/integration/message/MethodInvokingMessageHandlerTests.java

@@ -37,6 +37,7 @@ import org.springframework.integration.util.TestUtils.TestApplicationContext;
 
 /**
  * @author Mark Fisher
+ * @author Oleg Zhurakousky
  */
 public class MethodInvokingMessageHandlerTests {
 
@@ -46,9 +47,9 @@ public class MethodInvokingMessageHandlerTests {
 		handler.handleMessage(new GenericMessage<String>("test"));
 	}
 
-	@Test(expected = IllegalArgumentException.class)
+	@Test
 	public void invalidMethodWithNoArgs() {
-		new MethodInvokingMessageHandler(new TestSink(), "invalidMethodWithNoArgs");
+		new MethodInvokingMessageHandler(new TestSink(), "validMethodWithNoArgs");
 	}
 
 	@Test(expected = MessagingException.class)
@@ -118,7 +119,7 @@ public class MethodInvokingMessageHandlerTests {
 		public void validMethod(String s) {
 		}
 
-		public void invalidMethodWithNoArgs() {
+		public void validMethodWithNoArgs() {
 		}
 
 		public String methodWithReturnValue(String s) {