001/*
002 * Copyright 2002-2016 the original author or authors.
003 *
004 * Licensed under the Apache License, Version 2.0 (the "License");
005 * you may not use this file except in compliance with the License.
006 * You may obtain a copy of the License at
007 *
008 *      https://www.apache.org/licenses/LICENSE-2.0
009 *
010 * Unless required by applicable law or agreed to in writing, software
011 * distributed under the License is distributed on an "AS IS" BASIS,
012 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
013 * See the License for the specific language governing permissions and
014 * limitations under the License.
015 */
016
017package org.springframework.aop.aspectj;
018
019import java.io.Serializable;
020import java.lang.reflect.Method;
021import java.lang.reflect.Type;
022
023import org.springframework.aop.AfterAdvice;
024import org.springframework.aop.AfterReturningAdvice;
025import org.springframework.util.ClassUtils;
026import org.springframework.util.TypeUtils;
027
028/**
029 * Spring AOP advice wrapping an AspectJ after-returning advice method.
030 *
031 * @author Rod Johnson
032 * @author Juergen Hoeller
033 * @author Ramnivas Laddad
034 * @since 2.0
035 */
036@SuppressWarnings("serial")
037public class AspectJAfterReturningAdvice extends AbstractAspectJAdvice
038                implements AfterReturningAdvice, AfterAdvice, Serializable {
039
040        public AspectJAfterReturningAdvice(
041                        Method aspectJBeforeAdviceMethod, AspectJExpressionPointcut pointcut, AspectInstanceFactory aif) {
042
043                super(aspectJBeforeAdviceMethod, pointcut, aif);
044        }
045
046
047        @Override
048        public boolean isBeforeAdvice() {
049                return false;
050        }
051
052        @Override
053        public boolean isAfterAdvice() {
054                return true;
055        }
056
057        @Override
058        public void setReturningName(String name) {
059                setReturningNameNoCheck(name);
060        }
061
062        @Override
063        public void afterReturning(Object returnValue, Method method, Object[] args, Object target) throws Throwable {
064                if (shouldInvokeOnReturnValueOf(method, returnValue)) {
065                        invokeAdviceMethod(getJoinPointMatch(), returnValue, null);
066                }
067        }
068
069
070        /**
071         * Following AspectJ semantics, if a returning clause was specified, then the
072         * advice is only invoked if the returned value is an instance of the given
073         * returning type and generic type parameters, if any, match the assignment
074         * rules. If the returning type is Object, the advice is *always* invoked.
075         * @param returnValue the return value of the target method
076         * @return whether to invoke the advice method for the given return value
077         */
078        private boolean shouldInvokeOnReturnValueOf(Method method, Object returnValue) {
079                Class<?> type = getDiscoveredReturningType();
080                Type genericType = getDiscoveredReturningGenericType();
081                // If we aren't dealing with a raw type, check if generic parameters are assignable.
082                return (matchesReturnValue(type, method, returnValue) &&
083                                (genericType == null || genericType == type ||
084                                                TypeUtils.isAssignable(genericType, method.getGenericReturnType())));
085        }
086
087        /**
088         * Following AspectJ semantics, if a return value is null (or return type is void),
089         * then the return type of target method should be used to determine whether advice
090         * is invoked or not. Also, even if the return type is void, if the type of argument
091         * declared in the advice method is Object, then the advice must still get invoked.
092         * @param type the type of argument declared in advice method
093         * @param method the advice method
094         * @param returnValue the return value of the target method
095         * @return whether to invoke the advice method for the given return value and type
096         */
097        private boolean matchesReturnValue(Class<?> type, Method method, Object returnValue) {
098                if (returnValue != null) {
099                        return ClassUtils.isAssignableValue(type, returnValue);
100                }
101                else if (Object.class == type && void.class == method.getReturnType()) {
102                        return true;
103                }
104                else {
105                        return ClassUtils.isAssignable(type, method.getReturnType());
106                }
107        }
108
109}