/*
* 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.messaging.core;
import java.util.concurrent.CountDownLatch;
import java.util.concurrent.TimeUnit;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.springframework.beans.BeansException;
import org.springframework.beans.factory.BeanFactory;
import org.springframework.beans.factory.BeanFactoryAware;
import org.springframework.messaging.Message;
import org.springframework.messaging.MessageChannel;
import org.springframework.messaging.MessageDeliveryException;
import org.springframework.messaging.MessageHeaders;
import org.springframework.messaging.PollableChannel;
import org.springframework.messaging.support.MessageBuilder;
import org.springframework.messaging.support.MessageHeaderAccessor;
import org.springframework.util.Assert;
/**
* A messaging template that resolves destinations names to {@link MessageChannel}'s
* to send and receive messages from.
*
* @author Mark Fisher
* @author Rossen Stoyanchev
* @since 4.0
*/
public class GenericMessagingTemplate extends AbstractDestinationResolvingMessagingTemplate<MessageChannel>
implements BeanFactoryAware {
private volatile long sendTimeout = -1;
private volatile long receiveTimeout = -1;
private volatile boolean throwExceptionOnLateReply = false;
/**
* Configure the timeout value to use for send operations.
* @param sendTimeout the send timeout in milliseconds
*/
public void setSendTimeout(long sendTimeout) {
this.sendTimeout = sendTimeout;
}
/**
* Return the configured send operation timeout value.
*/
public long getSendTimeout() {
return this.sendTimeout;
}
/**
* Configure the timeout value to use for receive operations.
* @param receiveTimeout the receive timeout in milliseconds
*/
public void setReceiveTimeout(long receiveTimeout) {
this.receiveTimeout = receiveTimeout;
}
/**
* Return the configured receive operation timeout value.
*/
public long getReceiveTimeout() {
return this.receiveTimeout;
}
/**
* Whether the thread sending a reply should have an exception raised if the
* receiving thread isn't going to receive the reply either because it timed out,
* or because it already received a reply, or because it got an exception while
* sending the request message.
* <p>The default value is {@code false} in which case only a WARN message is logged.
* If set to {@code true} a {@link MessageDeliveryException} is raised in addition
* to the log message.
* @param throwExceptionOnLateReply whether to throw an exception or not
*/
public void setThrowExceptionOnLateReply(boolean throwExceptionOnLateReply) {
this.throwExceptionOnLateReply = throwExceptionOnLateReply;
}
@Override
public void setBeanFactory(BeanFactory beanFactory) throws BeansException {
super.setDestinationResolver(new BeanFactoryMessageChannelDestinationResolver(beanFactory));
}
@Override
protected final void doSend(MessageChannel channel, Message<?> message) {
Assert.notNull(channel, "'channel' is required");
MessageHeaderAccessor accessor = MessageHeaderAccessor.getAccessor(message, MessageHeaderAccessor.class);
if (accessor != null && accessor.isMutable()) {
accessor.setImmutable();
}
long timeout = this.sendTimeout;
boolean sent = (timeout >= 0 ? channel.send(message, timeout) : channel.send(message));
if (!sent) {
throw new MessageDeliveryException(message,
"failed to send message to channel '" + channel + "' within timeout: " + timeout);
}
}
@Override
protected final Message<?> doReceive(MessageChannel channel) {
Assert.notNull(channel, "'channel' is required");
Assert.state(channel instanceof PollableChannel, "A PollableChannel is required to receive messages");
long timeout = this.receiveTimeout;
Message<?> message = (timeout >= 0 ?
((PollableChannel) channel).receive(timeout) : ((PollableChannel) channel).receive());
if (message == null && this.logger.isTraceEnabled()) {
this.logger.trace("Failed to receive message from channel '" + channel + "' within timeout: " + timeout);
}
return message;
}
@Override
protected final Message<?> doSendAndReceive(MessageChannel channel, Message<?> requestMessage) {
Assert.notNull(channel, "'channel' is required");
Object originalReplyChannelHeader = requestMessage.getHeaders().getReplyChannel();
Object originalErrorChannelHeader = requestMessage.getHeaders().getErrorChannel();
TemporaryReplyChannel tempReplyChannel = new TemporaryReplyChannel();
requestMessage = MessageBuilder.fromMessage(requestMessage).setReplyChannel(tempReplyChannel).
setErrorChannel(tempReplyChannel).build();
try {
doSend(channel, requestMessage);
}
catch (RuntimeException ex) {
tempReplyChannel.setSendFailed(true);
throw ex;
}
Message<?> replyMessage = this.doReceive(tempReplyChannel);
if (replyMessage != null) {
replyMessage = MessageBuilder.fromMessage(replyMessage)
.setHeader(MessageHeaders.REPLY_CHANNEL, originalReplyChannelHeader)
.setHeader(MessageHeaders.ERROR_CHANNEL, originalErrorChannelHeader)
.build();
}
return replyMessage;
}
/**
* A temporary channel for receiving a single reply message.
*/
private class TemporaryReplyChannel implements PollableChannel {
private final Log logger = LogFactory.getLog(TemporaryReplyChannel.class);
private final CountDownLatch replyLatch = new CountDownLatch(1);
private volatile Message<?> replyMessage;
private volatile boolean hasReceived;
private volatile boolean hasTimedOut;
private volatile boolean hasSendFailed;
public void setSendFailed(boolean hasSendError) {
this.hasSendFailed = hasSendError;
}
@Override
public Message<?> receive() {
return this.receive(-1);
}
@Override
public Message<?> receive(long timeout) {
try {
if (GenericMessagingTemplate.this.receiveTimeout < 0) {
this.replyLatch.await();
this.hasReceived = true;
}
else {
if (this.replyLatch.await(GenericMessagingTemplate.this.receiveTimeout, TimeUnit.MILLISECONDS)) {
this.hasReceived = true;
}
else {
this.hasTimedOut = true;
}
}
}
catch (InterruptedException e) {
Thread.currentThread().interrupt();
}
return this.replyMessage;
}
@Override
public boolean send(Message<?> message) {
return this.send(message, -1);
}
@Override
public boolean send(Message<?> message, long timeout) {
this.replyMessage = message;
boolean alreadyReceivedReply = this.hasReceived;
this.replyLatch.countDown();
String errorDescription = null;
if (this.hasTimedOut) {
errorDescription = "Reply message received but the receiving thread has exited due to a timeout";
}
else if (alreadyReceivedReply) {
errorDescription = "Reply message received but the receiving thread has already received a reply";
}
else if (this.hasSendFailed) {
errorDescription = "Reply message received but the receiving thread has exited due to " +
"an exception while sending the request message";
}
if (errorDescription != null) {
if (logger.isWarnEnabled()) {
logger.warn(errorDescription + ":" + message);
}
if (GenericMessagingTemplate.this.throwExceptionOnLateReply) {
throw new MessageDeliveryException(message, errorDescription);
}
}
return true;
}
}
}