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.support;
018
019import org.springframework.messaging.Message;
020import org.springframework.messaging.MessageChannel;
021
022/**
023 * A simpler interceptor that calls {@link MessageHeaderAccessor#setImmutable()}
024 * on the headers of messages passed through the preSend method.
025 *
026 * <p>When configured as the last interceptor in a chain, it allows the component
027 * sending the message to leave headers mutable for interceptors to modify prior
028 * to the message actually being sent and exposed to concurrent access.
029 *
030 * @author Rossen Stoyanchev
031 * @since 4.1.2
032 */
033public class ImmutableMessageChannelInterceptor extends ChannelInterceptorAdapter {
034
035        @Override
036        public Message<?> preSend(Message<?> message, MessageChannel channel) {
037                MessageHeaderAccessor accessor = MessageHeaderAccessor.getAccessor(message, MessageHeaderAccessor.class);
038                if (accessor != null && accessor.isMutable()) {
039                        accessor.setImmutable();
040                }
041                return message;
042        }
043
044}