/*
* 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 org.springframework.messaging.Message;
import org.springframework.messaging.converter.MessageConversionException;
import org.springframework.messaging.converter.MessageConverter;
/**
* An extension of {@link AbstractMessageSendingTemplate} that adds support for
* receive style operations as defined by {@link MessageReceivingOperations}.
*
* @author Mark Fisher
* @author Rossen Stoyanchev
* @author Stephane Nicoll
* @since 4.1
*/
public abstract class AbstractMessageReceivingTemplate<D> extends AbstractMessageSendingTemplate<D>
implements MessageReceivingOperations<D> {
@Override
public Message<?> receive() {
return doReceive(getRequiredDefaultDestination());
}
@Override
public Message<?> receive(D destination) {
return doReceive(destination);
}
/**
* Actually receive a message from the given destination.
* @param destination the target destination
* @return the received message, possibly {@code null} if the message could not
* be received, for example due to a timeout
*/
protected abstract Message<?> doReceive(D destination);
@Override
public <T> T receiveAndConvert(Class<T> targetClass) {
return receiveAndConvert(getRequiredDefaultDestination(), targetClass);
}
@Override
public <T> T receiveAndConvert(D destination, Class<T> targetClass) {
Message<?> message = doReceive(destination);
if (message != null) {
return doConvert(message, targetClass);
}
else {
return null;
}
}
/**
* Convert from the given message to the given target class.
* @param message the message to convert
* @param targetClass the target class to convert the payload to
* @return the converted payload of the reply message (never {@code null})
*/
@SuppressWarnings("unchecked")
protected <T> T doConvert(Message<?> message, Class<T> targetClass) {
MessageConverter messageConverter = getMessageConverter();
T value = (T) messageConverter.fromMessage(message, targetClass);
if (value == null) {
throw new MessageConversionException(message, "Unable to convert payload [" + message.getPayload() +
"] to type [" + targetClass + "] using converter [" + messageConverter + "]");
}
return value;
}
}