001/* 002 * Copyright 2002-2017 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.context.event; 018 019import java.lang.reflect.Constructor; 020 021import org.aopalliance.intercept.MethodInterceptor; 022import org.aopalliance.intercept.MethodInvocation; 023 024import org.springframework.beans.factory.InitializingBean; 025import org.springframework.context.ApplicationEvent; 026import org.springframework.context.ApplicationEventPublisher; 027import org.springframework.context.ApplicationEventPublisherAware; 028 029/** 030 * {@link MethodInterceptor Interceptor} that publishes an 031 * {@code ApplicationEvent} to all {@code ApplicationListeners} 032 * registered with an {@code ApplicationEventPublisher} after each 033 * <i>successful</i> method invocation. 034 * 035 * <p>Note that this interceptor is only capable of publishing <i>stateless</i> 036 * events configured via the 037 * {@link #setApplicationEventClass "applicationEventClass"} property. 038 * 039 * @author Dmitriy Kopylenko 040 * @author Juergen Hoeller 041 * @author Rick Evans 042 * @see #setApplicationEventClass 043 * @see org.springframework.context.ApplicationEvent 044 * @see org.springframework.context.ApplicationListener 045 * @see org.springframework.context.ApplicationEventPublisher 046 * @see org.springframework.context.ApplicationContext 047 */ 048public class EventPublicationInterceptor 049 implements MethodInterceptor, ApplicationEventPublisherAware, InitializingBean { 050 051 private Constructor<?> applicationEventClassConstructor; 052 053 private ApplicationEventPublisher applicationEventPublisher; 054 055 056 /** 057 * Set the application event class to publish. 058 * <p>The event class <b>must</b> have a constructor with a single 059 * {@code Object} argument for the event source. The interceptor 060 * will pass in the invoked object. 061 * @throws IllegalArgumentException if the supplied {@code Class} is 062 * {@code null} or if it is not an {@code ApplicationEvent} subclass or 063 * if it does not expose a constructor that takes a single {@code Object} argument 064 */ 065 public void setApplicationEventClass(Class<?> applicationEventClass) { 066 if (ApplicationEvent.class == applicationEventClass || 067 !ApplicationEvent.class.isAssignableFrom(applicationEventClass)) { 068 throw new IllegalArgumentException("'applicationEventClass' needs to extend ApplicationEvent"); 069 } 070 try { 071 this.applicationEventClassConstructor = applicationEventClass.getConstructor(Object.class); 072 } 073 catch (NoSuchMethodException ex) { 074 throw new IllegalArgumentException("ApplicationEvent class [" + 075 applicationEventClass.getName() + "] does not have the required Object constructor: " + ex); 076 } 077 } 078 079 @Override 080 public void setApplicationEventPublisher(ApplicationEventPublisher applicationEventPublisher) { 081 this.applicationEventPublisher = applicationEventPublisher; 082 } 083 084 @Override 085 public void afterPropertiesSet() throws Exception { 086 if (this.applicationEventClassConstructor == null) { 087 throw new IllegalArgumentException("Property 'applicationEventClass' is required"); 088 } 089 } 090 091 092 @Override 093 public Object invoke(MethodInvocation invocation) throws Throwable { 094 Object retVal = invocation.proceed(); 095 096 ApplicationEvent event = (ApplicationEvent) 097 this.applicationEventClassConstructor.newInstance(invocation.getThis()); 098 this.applicationEventPublisher.publishEvent(event); 099 100 return retVal; 101 } 102 103}