Add Retryable interface for proxies advising @Retryable beans

This is purely a marker interface, but might be useful for other tools
looking to apply retry advice (they should usually not bother if the
bean already implements Retryable)

README.md

@@ -260,6 +260,8 @@ for a random backoff between 100 and 500 milliseconds and up to 12 attempts. The
 
 The `@EnableRetry` annotation also looks for beans of type `Sleeper` and other strategies used in the `RetryTemplate` and interceptors to control the beviour of the retry at runtime.
 
+The `@EnableRetry` annotation creates proxies for `@Retryable` beans, and the proxies (so the bean instances in the application) have the `Retryable` interface added to them. This is purely a marker interface, but might be useful for other tools looking to apply retry advice (they should usually not bother if the bean already implements `Retryable`).
+
 ### XML Configuration
 
 Here is an example of declarative iteration using Spring AOP to repeat a service call to a method called `remoteCall` (for more detail on how to configure AOP interceptors see the Spring User Guide):

src/main/java/org/springframework/retry/annotation/AnnotationAwareRetryOperationsInterceptor.java

@@ -115,7 +115,6 @@ public class AnnotationAwareRetryOperationsInterceptor implements MethodIntercep
 					} else {
 						delegate = getStatelessInterceptor(target, method, retryable);
 					}
-					// TODO: allow declaring class to specify @Recover methods
 					delegates.put(method, delegate);
 				}
 			}

src/main/java/org/springframework/retry/annotation/RetryConfiguration.java

@@ -23,6 +23,8 @@ import java.util.Set;
 import javax.annotation.PostConstruct;
 
 import org.aopalliance.aop.Advice;
+import org.springframework.aop.ClassFilter;
+import org.springframework.aop.IntroductionAdvisor;
 import org.springframework.aop.Pointcut;
 import org.springframework.aop.support.AbstractPointcutAdvisor;
 import org.springframework.aop.support.ComposablePointcut;
@@ -49,7 +51,7 @@ import org.springframework.retry.policy.RetryContextCache;
 @SuppressWarnings("serial")
 @Configuration
 public class RetryConfiguration extends AbstractPointcutAdvisor implements
-		BeanFactoryAware {
+		IntroductionAdvisor, BeanFactoryAware {
 
 	private Advice advice;
 
@@ -86,6 +88,20 @@ public class RetryConfiguration extends AbstractPointcutAdvisor implements
 		}
 	}
 
+	@Override
+	public ClassFilter getClassFilter() {
+		return pointcut.getClassFilter();
+	}
+
+	@Override
+	public Class<?>[] getInterfaces() {
+		return new Class[] { org.springframework.retry.interceptor.Retryable.class };
+	}
+
+	@Override
+	public void validateInterfaces() throws IllegalArgumentException {
+	}
+
 	@Override
 	public Advice getAdvice() {
 		return this.advice;

src/main/java/org/springframework/retry/interceptor/RetryOperationsInterceptor.java

@@ -17,6 +17,7 @@ import java.util.Arrays;
 
 import org.aopalliance.intercept.MethodInterceptor;
 import org.aopalliance.intercept.MethodInvocation;
+import org.springframework.aop.IntroductionInterceptor;
 import org.springframework.aop.ProxyMethodInvocation;
 import org.springframework.retry.RecoveryCallback;
 import org.springframework.retry.RetryCallback;
@@ -41,7 +42,7 @@ import org.springframework.util.Assert;
  * @author Rob Harrop
  * @author Dave Syer
  */
-public class RetryOperationsInterceptor implements MethodInterceptor {
+public class RetryOperationsInterceptor implements IntroductionInterceptor {
 
 	private RetryOperations retryOperations = new RetryTemplate();
 	private MethodInvocationRecoverer<?> recoverer;
@@ -54,6 +55,11 @@ public class RetryOperationsInterceptor implements MethodInterceptor {
 	public void setRecoverer(MethodInvocationRecoverer<?> recoverer) {
 		this.recoverer = recoverer;
 	}
+	
+	@Override
+	public boolean implementsInterface(Class<?> intf) {
+		return Retryable.class.isAssignableFrom(intf);
+	}
 
 	public Object invoke(final MethodInvocation invocation) throws Throwable {
 

src/main/java/org/springframework/retry/interceptor/Retryable.java

@@ -0,0 +1,28 @@
+/*
+ * Copyright 2013-2014 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.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.springframework.retry.interceptor;
+
+/**
+ * Marker interface for proxies that are providing retryable behaviour. Can be added by
+ * proxy creators that use the {@link RetryOperationsInterceptor} and
+ * {@link StatefulRetryOperationsInterceptor}.
+ * @author Dave Syer
+ *
+ */
+public interface Retryable {
+
+}

src/main/java/org/springframework/retry/interceptor/StatefulRetryOperationsInterceptor.java

@@ -22,6 +22,7 @@ import org.aopalliance.intercept.MethodInterceptor;
 import org.aopalliance.intercept.MethodInvocation;
 import org.apache.commons.logging.Log;
 import org.apache.commons.logging.LogFactory;
+import org.springframework.aop.IntroductionInterceptor;
 import org.springframework.retry.RecoveryCallback;
 import org.springframework.retry.RetryCallback;
 import org.springframework.retry.RetryContext;
@@ -51,7 +52,7 @@ import org.springframework.util.ObjectUtils;
  * 
  * @author Dave Syer
  */
-public class StatefulRetryOperationsInterceptor implements MethodInterceptor {
+public class StatefulRetryOperationsInterceptor implements IntroductionInterceptor {
 
 	private transient Log logger = LogFactory.getLog(getClass());
 
@@ -105,6 +106,11 @@ public class StatefulRetryOperationsInterceptor implements MethodInterceptor {
 		this.newMethodArgumentsIdentifier = newMethodArgumentsIdentifier;
 	}
 
+	@Override
+	public boolean implementsInterface(Class<?> intf) {
+		return Retryable.class.isAssignableFrom(intf);
+	}
+
 	/**
 	 * Wrap the method invocation in a stateful retry with the policy and other helpers
 	 * provided. If there is a failure the exception will generally be re-thrown. The only

src/test/java/org/springframework/retry/annotation/EnableRetryTests.java

@@ -18,16 +18,15 @@ package org.springframework.retry.annotation;
 
 import static org.junit.Assert.assertEquals;
 import static org.junit.Assert.assertNotNull;
+import static org.junit.Assert.assertTrue;
 import static org.junit.Assert.fail;
 
 import org.junit.Test;
+import org.springframework.aop.support.AopUtils;
 import org.springframework.context.annotation.AnnotationConfigApplicationContext;
 import org.springframework.context.annotation.Bean;
 import org.springframework.context.annotation.Configuration;
 import org.springframework.context.annotation.EnableAspectJAutoProxy;
-import org.springframework.retry.annotation.EnableRetry;
-import org.springframework.retry.annotation.Recover;
-import org.springframework.retry.annotation.Retryable;
 import org.springframework.retry.backoff.Sleeper;
 
 /**
@@ -46,6 +45,16 @@ public class EnableRetryTests {
 		context.close();
 	}
 
+	@Test
+	public void marker() {
+		AnnotationConfigApplicationContext context = new AnnotationConfigApplicationContext(
+				TestConfiguration.class);
+		Service service = context.getBean(Service.class);
+		assertTrue(AopUtils.isCglibProxy(service));
+		assertTrue(service instanceof org.springframework.retry.interceptor.Retryable);
+		context.close();
+	}
+
 	@Test
 	public void recovery() {
 		AnnotationConfigApplicationContext context = new AnnotationConfigApplicationContext(