1 /*
2 * Copyright 2006-2007 the original author or authors.
3 *
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
7 *
8 * http://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
15 */
16
17 package org.springframework.batch.item.jms;
18
19 import javax.jms.JMSException;
20 import javax.jms.Message;
21
22 import org.springframework.batch.item.UnexpectedInputException;
23 import org.springframework.retry.interceptor.MethodArgumentsKeyGenerator;
24
25 /**
26 * A {@link MethodArgumentsKeyGenerator} for JMS
27 *
28 * @author Dave Syer
29 *
30 */
31 public class JmsMethodArgumentsKeyGenerator implements MethodArgumentsKeyGenerator {
32
33 /**
34 * If the message is a {@link Message} then returns the JMS message ID.
35 * Otherwise just return the first argument.
36 *
37 * @see org.springframework.retry.interceptor.MethodArgumentsKeyGenerator#getKey(Object[])
38 *
39 * @throws UnexpectedInputException if the JMS id cannot be determined from
40 * a JMS Message
41 * @throws IllegalArgumentException if the arguments are empty
42 */
43 @Override
44 public Object getKey(Object[] items) {
45 for (Object item : items) {
46 if (item instanceof Message) {
47 try {
48 return ((Message) item).getJMSMessageID();
49 }
50 catch (JMSException e) {
51 throw new UnexpectedInputException("Could not extract message ID", e);
52 }
53 }
54 }
55 if (items.length == 0) {
56 throw new IllegalArgumentException(
57 "Method parameters are empty. The key generator cannot determine a unique key.");
58 }
59 return items[0];
60 }
61
62 }