/*
 * Copyright 2002-2016 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.aop.aspectj;

import java.io.Serializable;
import java.lang.reflect.Method;
import java.lang.reflect.Type;

import org.springframework.aop.AfterAdvice;
import org.springframework.aop.AfterReturningAdvice;
import org.springframework.lang.Nullable;
import org.springframework.util.ClassUtils;
import org.springframework.util.TypeUtils;

Spring AOP advice wrapping an AspectJ after-returning advice method.
Author:
Rod Johnson, Juergen Hoeller, Ramnivas Laddad
Since:
2.0/**
 * Spring AOP advice wrapping an AspectJ after-returning advice method.
 *
 * @author Rod Johnson
 * @author Juergen Hoeller
 * @author Ramnivas Laddad
 * @since 2.0
 */
@SuppressWarnings("serial")
public class AspectJAfterReturningAdvice extends AbstractAspectJAdvice
		implements AfterReturningAdvice, AfterAdvice, Serializable {

	public AspectJAfterReturningAdvice(
			Method aspectJBeforeAdviceMethod, AspectJExpressionPointcut pointcut, AspectInstanceFactory aif) {

		super(aspectJBeforeAdviceMethod, pointcut, aif);
	}


	@Override
	public boolean isBeforeAdvice() {
		return false;
	}

	@Override
	public boolean isAfterAdvice() {
		return true;
	}

	@Override
	public void setReturningName(String name) {
		setReturningNameNoCheck(name);
	}

	@Override
	public void afterReturning(@Nullable Object returnValue, Method method, Object[] args, @Nullable Object target) throws Throwable {
		if (shouldInvokeOnReturnValueOf(method, returnValue)) {
			invokeAdviceMethod(getJoinPointMatch(), returnValue, null);
		}
	}


	
Following AspectJ semantics, if a returning clause was specified, then the
advice is only invoked if the returned value is an instance of the given
returning type and generic type parameters, if any, match the assignment
rules. If the returning type is Object, the advice is *always* invoked.
Params:
returnValue – the return value of the target method
Returns:
whether to invoke the advice method for the given return value/**
	 * Following AspectJ semantics, if a returning clause was specified, then the
	 * advice is only invoked if the returned value is an instance of the given
	 * returning type and generic type parameters, if any, match the assignment
	 * rules. If the returning type is Object, the advice is *always* invoked.
	 * @param returnValue the return value of the target method
	 * @return whether to invoke the advice method for the given return value
	 */
	private boolean shouldInvokeOnReturnValueOf(Method method, @Nullable Object returnValue) {
		Class<?> type = getDiscoveredReturningType();
		Type genericType = getDiscoveredReturningGenericType();
		// If we aren't dealing with a raw type, check if generic parameters are assignable.
		return (matchesReturnValue(type, method, returnValue) &&
				(genericType == null || genericType == type ||
						TypeUtils.isAssignable(genericType, method.getGenericReturnType())));
	}

	
Following AspectJ semantics, if a return value is null (or return type is void),
then the return type of target method should be used to determine whether advice
is invoked or not. Also, even if the return type is void, if the type of argument
declared in the advice method is Object, then the advice must still get invoked.
Params:
type – the type of argument declared in advice method
method – the advice method
returnValue – the return value of the target method
Returns:
whether to invoke the advice method for the given return value and type/**
	 * Following AspectJ semantics, if a return value is null (or return type is void),
	 * then the return type of target method should be used to determine whether advice
	 * is invoked or not. Also, even if the return type is void, if the type of argument
	 * declared in the advice method is Object, then the advice must still get invoked.
	 * @param type the type of argument declared in advice method
	 * @param method the advice method
	 * @param returnValue the return value of the target method
	 * @return whether to invoke the advice method for the given return value and type
	 */
	private boolean matchesReturnValue(Class<?> type, Method method, @Nullable Object returnValue) {
		if (returnValue != null) {
			return ClassUtils.isAssignableValue(type, returnValue);
		}
		else if (Object.class == type && void.class == method.getReturnType()) {
			return true;
		}
		else {
			return ClassUtils.isAssignable(type, method.getReturnType());
		}
	}

}