001/*
002 * Copyright 2006-2007 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.batch.item.jms;
018
019import javax.jms.JMSException;
020import javax.jms.Message;
021
022import org.springframework.batch.item.UnexpectedInputException;
023import org.springframework.retry.interceptor.MethodArgumentsKeyGenerator;
024
025/**
026 * A {@link MethodArgumentsKeyGenerator} for JMS 
027 * 
028 * @author Dave Syer
029 * 
030 */
031public class JmsMethodArgumentsKeyGenerator implements MethodArgumentsKeyGenerator {
032
033        /**
034         * If the message is a {@link Message} then returns the JMS message ID.
035         * Otherwise just return the first argument.
036         * 
037         * @see org.springframework.retry.interceptor.MethodArgumentsKeyGenerator#getKey(Object[])
038         * 
039         * @throws UnexpectedInputException if the JMS id cannot be determined from
040         * a JMS Message
041         * @throws IllegalArgumentException if the arguments are empty
042         */
043    @Override
044        public Object getKey(Object[] items) {
045                for (Object item : items) {
046                        if (item instanceof Message) {
047                                try {
048                                        return ((Message) item).getJMSMessageID();
049                                }
050                                catch (JMSException e) {
051                                        throw new UnexpectedInputException("Could not extract message ID", e);
052                                }
053                        }
054                }
055                if (items.length == 0) {
056                        throw new IllegalArgumentException(
057                                        "Method parameters are empty.  The key generator cannot determine a unique key.");
058                }
059                return items[0];
060        }
061
062}