1 /***
2 *
3 * Copyright 2005 LogicBlaze, Inc.
4 *
5 * Licensed under the Apache License, Version 2.0 (the "License");
6 * you may not use this file except in compliance with the License.
7 * You may obtain a copy of the License at
8 *
9 * http://www.apache.org/licenses/LICENSE-2.0
10 *
11 * Unless required by applicable law or agreed to in writing, software
12 * distributed under the License is distributed on an "AS IS" BASIS,
13 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
14 * See the License for the specific language governing permissions and
15 * limitations under the License.
16 *
17 **/
18 package org.logicblaze.lingo.jms.impl;
19
20 import org.apache.commons.logging.Log;
21 import org.apache.commons.logging.LogFactory;
22 import org.logicblaze.lingo.ResultJoinStrategy;
23 import org.logicblaze.lingo.jms.ReplyHandler;
24 import org.logicblaze.lingo.jms.marshall.Marshaller;
25 import org.springframework.remoting.support.RemoteInvocationResult;
26
27 import javax.jms.JMSException;
28 import javax.jms.Message;
29
30 /***
31 * A {@link org.logicblaze.lingo.jms.ReplyHandler} which can handle join
32 * multiple results to the same request which are then aggregated together into
33 * a single value.
34 *
35 * @version $Revision$
36 */
37 public class ResultJoinHandler implements ReplyHandler {
38
39 private static final Log log = LogFactory.getLog(ResultJoinHandler.class);
40
41 private Marshaller marshaller;
42 private ResultJoinStrategy joinStrategy;
43 private Object lock = new Object();
44 private int responseCount;
45 private RemoteInvocationResult result;
46 private long timeout = 2000;
47
48 public ResultJoinHandler(Marshaller marshaller, ResultJoinStrategy joinStrategy) {
49 this.marshaller = marshaller;
50 this.joinStrategy = joinStrategy;
51 }
52
53 public boolean handle(Message message) throws JMSException {
54 RemoteInvocationResult newResult = marshaller.extractInvocationResult(message);
55 synchronized (lock) {
56 ++responseCount;
57 if (result == null) {
58 result = newResult;
59 }
60 else {
61 result = joinStrategy.mergeResponses(result, newResult, responseCount);
62 }
63 if (joinStrategy.unblockCallerThread(result, responseCount)) {
64 lock.notifyAll();
65 }
66 }
67 return joinStrategy.removeHandler(result, responseCount);
68 }
69
70 /***
71 * This method will block the calling thread until the result is available.
72 */
73 public RemoteInvocationResult waitForResult() {
74 while (true) {
75 synchronized (lock) {
76 if (result != null) {
77 return result;
78 }
79 try {
80 lock.wait(timeout);
81 }
82 catch (InterruptedException e) {
83 log.debug("Ignored interrupt exception: " + e, e);
84 }
85 }
86 }
87 }
88
89 public RemoteInvocationResult pollResult() {
90 synchronized (lock) {
91 return result;
92 }
93 }
94
95 public int getResponseCount() {
96 synchronized (lock) {
97 return responseCount;
98 }
99 }
100
101 public long getTimeout() {
102 return timeout;
103 }
104
105 /***
106 * Sets the {@link #wait(long)} method timeout period before resuming the
107 * wait.
108 */
109 public void setTimeout(long timeout) {
110 this.timeout = timeout;
111 }
112
113 }