001/*
002 * Copyright 2002-2014 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.messaging.converter;
018
019import org.springframework.messaging.Message;
020import org.springframework.messaging.MessageHeaders;
021import org.springframework.messaging.support.MessageBuilder;
022import org.springframework.messaging.support.MessageHeaderAccessor;
023import org.springframework.util.ClassUtils;
024
025/**
026 * A simple converter that simply unwraps the message payload as long as it matches the
027 * expected target class. Or reversely, simply wraps the payload in a message.
028 *
029 * <p>Note that this converter ignores any content type information that may be present in
030 * message headers and should not be used if payload conversion is actually required.
031 *
032 * @author Rossen Stoyanchev
033 * @since 4.0
034 */
035public class SimpleMessageConverter implements MessageConverter {
036
037        @Override
038        public Object fromMessage(Message<?> message, Class<?> targetClass) {
039                Object payload = message.getPayload();
040                if (targetClass == null) {
041                        return payload;
042                }
043                return (ClassUtils.isAssignableValue(targetClass, payload) ? payload : null);
044        }
045
046        @Override
047        public Message<?> toMessage(Object payload, MessageHeaders headers) {
048                if (payload == null) {
049                        return null;
050                }
051                if (headers != null) {
052                        MessageHeaderAccessor accessor = MessageHeaderAccessor.getAccessor(headers, MessageHeaderAccessor.class);
053                        if (accessor != null && accessor.isMutable()) {
054                                return MessageBuilder.createMessage(payload, accessor.getMessageHeaders());
055                        }
056                }
057                return MessageBuilder.withPayload(payload).copyHeaders(headers).build();
058        }
059
060}