/*
* Copyright 2014-2017 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.integration.handler.advice;
import org.aopalliance.intercept.MethodInterceptor;
import org.aopalliance.intercept.MethodInvocation;
import org.springframework.beans.BeansException;
import org.springframework.beans.factory.BeanFactory;
import org.springframework.beans.factory.BeanFactoryAware;
import org.springframework.integration.IntegrationMessageHeaderAccessor;
import org.springframework.integration.MessageRejectedException;
import org.springframework.integration.core.MessageSelector;
import org.springframework.integration.core.MessagingTemplate;
import org.springframework.integration.support.DefaultMessageBuilderFactory;
import org.springframework.integration.support.MessageBuilderFactory;
import org.springframework.integration.support.utils.IntegrationUtils;
import org.springframework.messaging.Message;
import org.springframework.messaging.MessageChannel;
import org.springframework.messaging.MessageHandler;
import org.springframework.util.Assert;
/**
* The {@link MethodInterceptor} implementation for the
* <a href="http://www.eaipatterns.com/IdempotentReceiver.html">Idempotent Receiver</a>
* E.I. Pattern.
* <p>
* This {@link MethodInterceptor} works like a {@code MessageFilter} if {@link #discardChannel}
* is provided or {@link #throwExceptionOnRejection} is set to {@code true}.
* However if those properties aren't provided, this interceptor will create an new {@link Message}
* with a {@link IntegrationMessageHeaderAccessor#DUPLICATE_MESSAGE} header when the
* {@code requestMessage} isn't accepted by {@link MessageSelector}.
* <p>
* The {@code idempotent filtering} logic depends on the provided {@link MessageSelector}.
* <p>
* This class is designed to be used only for the {@link MessageHandler#handleMessage},
* method.
*
* @author Artem Bilan
* @since 4.1
* @see org.springframework.integration.selector.MetadataStoreSelector
* @see org.springframework.integration.config.IdempotentReceiverAutoProxyCreatorInitializer
*/
public class IdempotentReceiverInterceptor extends AbstractHandleMessageAdvice implements BeanFactoryAware {
private final MessagingTemplate messagingTemplate = new MessagingTemplate();
private final MessageSelector messageSelector;
private volatile MessageChannel discardChannel;
private volatile boolean throwExceptionOnRejection;
private volatile MessageBuilderFactory messageBuilderFactory = new DefaultMessageBuilderFactory();
private volatile boolean messageBuilderFactorySet;
private BeanFactory beanFactory;
public IdempotentReceiverInterceptor(MessageSelector messageSelector) {
Assert.notNull(messageSelector, "'messageSelector' must not be null");
this.messageSelector = messageSelector;
}
/**
* Specify the timeout value for sending to the discard channel.
* @param timeout the timeout in milliseconds
*/
public void setTimeout(long timeout) {
this.messagingTemplate.setSendTimeout(timeout);
}
/**
* Specify whether this interceptor should throw a
* {@link MessageRejectedException} when its selector does not accept a
* Message. The default value is <code>false</code> meaning that rejected
* Messages will be discarded or
* enriched with {@link IntegrationMessageHeaderAccessor#DUPLICATE_MESSAGE}
* header and returned as normal to the {@code invocation.proceed()}.
* Typically this value would <em>not</em> be <code>true</code> when
* a discard channel is provided, but if it is, it will cause the
* exception to be thrown <em>after</em>
* the Message is sent to the discard channel,
* @param throwExceptionOnRejection true if an exception should be thrown.
* @see #setDiscardChannel(MessageChannel)
*/
public void setThrowExceptionOnRejection(boolean throwExceptionOnRejection) {
this.throwExceptionOnRejection = throwExceptionOnRejection;
}
/**
* Specify a channel where rejected Messages should be sent. If the discard
* channel is null (the default), duplicate Messages will be enriched with
* {@link IntegrationMessageHeaderAccessor#DUPLICATE_MESSAGE} header
* and returned as normal to the {@code invocation.proceed()}. However,
* the 'throwExceptionOnRejection' flag determines whether rejected Messages
* trigger an exception. That value is evaluated regardless of the presence
* of a discard channel.
* <p>
* If there is needed just silently 'drop' rejected messages configure the
* {@link #discardChannel} to the {@code nullChannel}.
* @param discardChannel The discard channel.
* @see #setThrowExceptionOnRejection(boolean)
*/
public void setDiscardChannel(MessageChannel discardChannel) {
this.discardChannel = discardChannel;
}
@Override
public void setBeanFactory(BeanFactory beanFactory) throws BeansException {
this.beanFactory = beanFactory;
}
protected MessageBuilderFactory getMessageBuilderFactory() {
if (!this.messageBuilderFactorySet) {
if (this.beanFactory != null) {
this.messageBuilderFactory = IntegrationUtils.getMessageBuilderFactory(this.beanFactory);
}
this.messageBuilderFactorySet = true;
}
return this.messageBuilderFactory;
}
@Override
protected Object doInvoke(MethodInvocation invocation, Message<?> message) throws Throwable {
boolean accept = this.messageSelector.accept(message);
if (!accept) {
boolean discarded = false;
if (this.discardChannel != null) {
this.messagingTemplate.send(this.discardChannel, message);
discarded = true;
}
if (this.throwExceptionOnRejection) {
throw new MessageRejectedException(message, "IdempotentReceiver '" + this
+ "' rejected duplicate Message: " + message);
}
if (!discarded) {
invocation.getArguments()[0] = getMessageBuilderFactory().fromMessage(message)
.setHeader(IntegrationMessageHeaderAccessor.DUPLICATE_MESSAGE, true).build();
}
else {
return null;
}
}
return invocation.proceed();
}
}