/*
* Copyright 2002-2014 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.amqp.remoting.service;
import org.springframework.amqp.AmqpRejectAndDontRequeueException;
import org.springframework.amqp.core.Address;
import org.springframework.amqp.core.AmqpTemplate;
import org.springframework.amqp.core.Message;
import org.springframework.amqp.core.MessageListener;
import org.springframework.amqp.core.MessageProperties;
import org.springframework.amqp.remoting.client.AmqpProxyFactoryBean;
import org.springframework.amqp.support.converter.MessageConverter;
import org.springframework.amqp.support.converter.SimpleMessageConverter;
import org.springframework.remoting.support.RemoteInvocation;
import org.springframework.remoting.support.RemoteInvocationBasedExporter;
import org.springframework.remoting.support.RemoteInvocationResult;
/**
* This message listener exposes a plain java service via AMQP. Such services can be accessed via plain AMQP or via
* {@link AmqpProxyFactoryBean}.
*
* To configure this message listener so that it actually receives method calls via AMQP, it needs to be put into a
* listener container. See {@link MessageListener}.
*
* <p>
* When receiving a message, a service method is called according to the contained {@link RemoteInvocation}. The result
* of that invocation is returned as a {@link RemoteInvocationResult} contained in a message that is sent according to
* the <code>ReplyToAddress</code> of the received message.
*
* <p>
* Please note that this exporter does not use the {@link MessageConverter} of the injected {@link AmqpTemplate} to
* convert incoming calls and their results. Instead you have to directly inject the <code>MessageConverter</code> into
* this class.
*
* <p>
* This listener responds to "Request/Reply"-style messages as described <a href=
* "http://static.springsource.org/spring-amqp/reference/html/amqp.html#request-reply" >here</a>.
*
* @author David Bilge
* @since 1.2
*/
public class AmqpInvokerServiceExporter extends RemoteInvocationBasedExporter implements MessageListener {
private AmqpTemplate amqpTemplate;
private MessageConverter messageConverter = new SimpleMessageConverter();
@Override
public void onMessage(Message message) {
Address replyToAddress = message.getMessageProperties().getReplyToAddress();
if (replyToAddress == null) {
throw new AmqpRejectAndDontRequeueException("No replyToAddress in inbound AMQP Message");
}
Object invocationRaw = messageConverter.fromMessage(message);
if (invocationRaw == null || !(invocationRaw instanceof RemoteInvocation)) {
send(new RuntimeException("The message does not contain a RemoteInvocation payload"), replyToAddress);
return;
}
RemoteInvocation invocation = (RemoteInvocation) invocationRaw;
RemoteInvocationResult remoteInvocationResult = invokeAndCreateResult(invocation, getService());
send(remoteInvocationResult, replyToAddress);
}
private void send(Object object, Address replyToAddress) {
Message message = messageConverter.toMessage(object, new MessageProperties());
getAmqpTemplate().send(replyToAddress.getExchangeName(), replyToAddress.getRoutingKey(), message);
}
public AmqpTemplate getAmqpTemplate() {
return amqpTemplate;
}
/**
* The AMQP template to use for sending the return value.
*
* <p>
* Note that the exchange and routing key parameters on this template are ignored for these return messages. Instead
* of those the respective parameters from the original message's <code>returnAddress</code> are being used.
* <p>
* Also, the template's {@link MessageConverter} is not used for the reply.
*
* @param amqpTemplate The amqp template.
*
* @see #setMessageConverter(MessageConverter)
*/
public void setAmqpTemplate(AmqpTemplate amqpTemplate) {
this.amqpTemplate = amqpTemplate;
}
public MessageConverter getMessageConverter() {
return messageConverter;
}
/**
* Set the message converter for this remote service. Used to deserialize remote method calls and to serialize their
* return values.
* <p>
* The default converter is a SimpleMessageConverter, which is able to handle byte arrays, Strings, and Serializable
* Objects depending on the message content type header.
* <p>
* Note that this class never uses the message converter of the underlying {@link AmqpTemplate}!
*
* @param messageConverter The message converter.
*
* @see org.springframework.amqp.support.converter.SimpleMessageConverter
*/
public void setMessageConverter(MessageConverter messageConverter) {
this.messageConverter = messageConverter;
}
}