DATAREDIS-337 - Improve handling of overridden methods in MessageListenerAdapter.

Previously overriding message handler methods of the delegate passed to MessageListenerAdapter resulted in the message handler method called multiple times. We now make sure that a message handler method is only found and invoked  once.

Original pull request: #95.

src/main/java/org/springframework/data/redis/listener/adapter/MessageListenerAdapter.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2011-2013 the original author or authors.
+ * Copyright 2011-2014 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.
@@ -18,8 +18,8 @@ package org.springframework.data.redis.listener.adapter;
 import java.lang.reflect.InvocationTargetException;
 import java.lang.reflect.Method;
 import java.lang.reflect.Modifier;
-import java.util.ArrayList;
-import java.util.List;
+import java.util.HashSet;
+import java.util.Set;
 
 import org.apache.commons.logging.Log;
 import org.apache.commons.logging.LogFactory;
@@ -32,6 +32,7 @@ import org.springframework.data.redis.serializer.JdkSerializationRedisSerializer
 import org.springframework.data.redis.serializer.RedisSerializer;
 import org.springframework.data.redis.serializer.StringRedisSerializer;
 import org.springframework.util.Assert;
+import org.springframework.util.ClassUtils;
 import org.springframework.util.ObjectUtils;
 import org.springframework.util.ReflectionUtils;
 import org.springframework.util.ReflectionUtils.MethodCallback;
@@ -89,26 +90,28 @@ import org.springframework.util.StringUtils;
  * @author Juergen Hoeller
  * @author Costin Leau
  * @author Greg Turnquist
+ * @author Thomas Darimont
+ * @author Christoph Strobl
  * @see org.springframework.jms.listener.adapter.MessageListenerAdapter
  */
 public class MessageListenerAdapter implements InitializingBean, MessageListener {
 
+
 	private class MethodInvoker {
+
 		private final Object delegate;
 		private String methodName;
-
-		private List<Method> methods;
-		private boolean lenient = false;
+		private Set<Method> methods;
+		private boolean lenient;
 
 		MethodInvoker(Object delegate, final String methodName) {
+
 			this.delegate = delegate;
 			this.methodName = methodName;
+			this.lenient = delegate instanceof MessageListener;
+			this.methods = new HashSet<Method>();
 
-			lenient = delegate instanceof MessageListener;
-
-			Class<?> c = delegate.getClass();
-
-			methods = new ArrayList<Method>();
+			final Class<?> c = delegate.getClass();
 
 			ReflectionUtils.doWithMethods(c, new MethodCallback() {
 
@@ -117,17 +120,7 @@ public class MessageListenerAdapter implements InitializingBean, MessageListener
 					methods.add(method);
 				}
 
-			}, new MethodFilter() {
-				public boolean matches(Method method) {
-					if (Modifier.isPublic(method.getModifiers()) && methodName.equals(method.getName())) {
-						// check out the argument numbers
-						Class<?>[] parameterTypes = method.getParameterTypes();
-
-						return ((parameterTypes.length == 2 && String.class.equals(parameterTypes[1])) || parameterTypes.length == 1);
-					}
-					return false;
-				}
-			});
+			}, new MostSpecificMethodFilter(methodName, c));
 
 			Assert.isTrue(lenient || !methods.isEmpty(), "Cannot find a suitable method named [" + c.getName() + "#"
 					+ methodName + "] - is the method public and has the proper arguments?");
@@ -136,10 +129,22 @@ public class MessageListenerAdapter implements InitializingBean, MessageListener
 		void invoke(Object[] arguments) throws InvocationTargetException, IllegalAccessException {
 
 			Object[] message = new Object[] { arguments[0] };
+
 			for (Method m : methods) {
+
 				Class<?>[] types = m.getParameterTypes();
-				Object[] args = (types.length == 2 ? arguments : message);
+				Object[] args = //
+				types.length == 2 //
+						&& types[0].isInstance(arguments[0]) //
+						&& types[1].isInstance(arguments[1]) ? arguments : message;
+
+				if (!types[0].isInstance(args[0])) {
+					continue;
+				}
+
 				m.invoke(delegate, args);
+
+				return;
 			}
 		}
 
@@ -152,7 +157,7 @@ public class MessageListenerAdapter implements InitializingBean, MessageListener
 			return methodName;
 		}
 	}
-
+	
 	/**
 	 * Out-of-the-box value for the default listener method: "handleMessage".
 	 */
@@ -380,4 +385,34 @@ public class MessageListenerAdapter implements InitializingBean, MessageListener
 					+ "' with arguments " + ObjectUtils.nullSafeToString(arguments), ex);
 		}
 	}
+
+	/**
+	 * @since 1.4
+	 */
+	static final class MostSpecificMethodFilter implements MethodFilter {
+
+		private final String methodName;
+		private final Class<?> c;
+
+		MostSpecificMethodFilter(String methodName, Class<?> c) {
+
+			this.methodName = methodName;
+			this.c = c;
+		}
+
+		public boolean matches(Method method) {
+
+			if (Modifier.isPublic(method.getModifiers()) //
+					&& methodName.equals(method.getName()) //
+					&& method.equals(ClassUtils.getMostSpecificMethod(method, c))) {
+
+				// check out the argument numbers
+				Class<?>[] parameterTypes = method.getParameterTypes();
+
+				return ((parameterTypes.length == 2 && String.class.equals(parameterTypes[1])) || parameterTypes.length == 1);
+			}
+
+			return false;
+		}
+	}
 }