001/*
002 * Copyright 2002-2017 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 java.util.UUID;
020
021import org.springframework.messaging.MessageHeaders;
022import org.springframework.util.IdGenerator;
023
024/**
025 * A {@link org.springframework.messaging.support.MessageHeaderInitializer MessageHeaderInitializer}
026 * to customize the strategy for ID and TIMESTAMP message header generation.
027 *
028 * @author Rossen Stoyanchev
029 * @since 4.1
030 */
031public class IdTimestampMessageHeaderInitializer implements MessageHeaderInitializer {
032
033        private IdGenerator idGenerator;
034
035        private boolean enableTimestamp;
036
037
038        /**
039         * Configure the IdGenerator strategy to initialize {@code MessageHeaderAccessor}
040         * instances with.
041         * <p>By default this property is set to {@code null} in which case the default
042         * IdGenerator of {@link org.springframework.messaging.MessageHeaders} is used.
043         * <p>To have no ids generated at all, see {@link #setDisableIdGeneration()}.
044         */
045        public void setIdGenerator(IdGenerator idGenerator) {
046                this.idGenerator = idGenerator;
047        }
048
049        /**
050         * Return the configured {@code IdGenerator}, if any.
051         */
052        public IdGenerator getIdGenerator() {
053                return this.idGenerator;
054        }
055
056        /**
057         * A shortcut for calling {@link #setIdGenerator} with an id generation strategy
058         * to disable id generation completely.
059         */
060        public void setDisableIdGeneration() {
061                this.idGenerator = ID_VALUE_NONE_GENERATOR;
062        }
063
064        /**
065         * Whether to enable the automatic addition of the
066         * {@link org.springframework.messaging.MessageHeaders#TIMESTAMP} header on
067         * {@code MessageHeaderAccessor} instances being initialized.
068         * <p>By default this property is set to false.
069         */
070        public void setEnableTimestamp(boolean enableTimestamp) {
071                this.enableTimestamp = enableTimestamp;
072        }
073
074        /**
075         * Return whether the timestamp header is enabled or not.
076         */
077        public boolean isEnableTimestamp() {
078                return this.enableTimestamp;
079        }
080
081
082        @Override
083        public void initHeaders(MessageHeaderAccessor headerAccessor) {
084                headerAccessor.setIdGenerator(getIdGenerator());
085                headerAccessor.setEnableTimestamp(isEnableTimestamp());
086        }
087
088
089        private static final IdGenerator ID_VALUE_NONE_GENERATOR = new IdGenerator() {
090                @Override
091                public UUID generateId() {
092                        return MessageHeaders.ID_VALUE_NONE;
093                }
094        };
095
096}