001 /**
002 * Licensed to the Apache Software Foundation (ASF) under one or more
003 * contributor license agreements. See the NOTICE file distributed with
004 * this work for additional information regarding copyright ownership.
005 * The ASF licenses this file to You under the Apache License, Version 2.0
006 * (the "License"); you may not use this file except in compliance with
007 * the License. You may obtain a copy of the License at
008 *
009 * http://www.apache.org/licenses/LICENSE-2.0
010 *
011 * Unless required by applicable law or agreed to in writing, software
012 * distributed under the License is distributed on an "AS IS" BASIS,
013 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
014 * See the License for the specific language governing permissions and
015 * limitations under the License.
016 */
017 package org.apache.activemq.ra;
018
019 import java.lang.reflect.Method;
020
021 import javax.jms.Message;
022 import javax.jms.MessageListener;
023 import javax.resource.ResourceException;
024 import javax.resource.spi.endpoint.MessageEndpoint;
025 import org.apache.commons.logging.Log;
026 import org.apache.commons.logging.LogFactory;
027
028 /**
029 * @author <a href="mailto:michael.gaffney@panacya.com">Michael Gaffney </a>
030 */
031 public class MessageEndpointProxy implements MessageListener, MessageEndpoint {
032
033 private static final MessageEndpointState ALIVE = new MessageEndpointAlive();
034 private static final MessageEndpointState DEAD = new MessageEndpointDead();
035 private static final Log LOG = LogFactory.getLog(MessageEndpointProxy.class);
036
037 private static int proxyCount;
038 private final int proxyID;
039
040 private final MessageEndpoint endpoint;
041 private final MessageListener messageListener;
042 private MessageEndpointState state = ALIVE;
043
044 public MessageEndpointProxy(MessageEndpoint endpoint) {
045 if (!(endpoint instanceof MessageListener)) {
046 throw new IllegalArgumentException("MessageEndpoint is not a MessageListener");
047 }
048 messageListener = (MessageListener)endpoint;
049 proxyID = getID();
050 this.endpoint = endpoint;
051 }
052
053 private static int getID() {
054 return ++proxyCount;
055 }
056
057 public void beforeDelivery(Method method) throws NoSuchMethodException, ResourceException {
058 LOG.trace("Invoking MessageEndpoint.beforeDelivery()");
059 state.beforeDelivery(this, method);
060 }
061
062 public void onMessage(Message message) {
063 LOG.trace("Invoking MessageEndpoint.onMethod()");
064 state.onMessage(this, message);
065 }
066
067 public void afterDelivery() throws ResourceException {
068 LOG.trace("Invoking MessageEndpoint.afterDelivery()");
069 state.afterDelivery(this);
070 }
071
072 public void release() {
073 LOG.trace("Invoking MessageEndpoint.release()");
074 state.release(this);
075 }
076
077 public String toString() {
078 return "MessageEndpointProxy{ " + "proxyID: " + proxyID + ", endpoint: " + endpoint + " }";
079 }
080
081 private abstract static class MessageEndpointState {
082
083 public void beforeDelivery(MessageEndpointProxy proxy, Method method) throws NoSuchMethodException, ResourceException {
084 throw new IllegalStateException();
085 }
086
087 public void onMessage(MessageEndpointProxy proxy, Message message) {
088 throw new IllegalStateException();
089 }
090
091 public void afterDelivery(MessageEndpointProxy proxy) throws ResourceException {
092 throw new IllegalStateException();
093 }
094
095 public void release(MessageEndpointProxy proxy) {
096 throw new IllegalStateException();
097 }
098
099 protected final void transition(MessageEndpointProxy proxy, MessageEndpointState nextState) {
100 proxy.state = nextState;
101 nextState.enter(proxy);
102 }
103
104 protected void enter(MessageEndpointProxy proxy) {
105 }
106 }
107
108 private static class MessageEndpointAlive extends MessageEndpointState {
109
110 public void beforeDelivery(MessageEndpointProxy proxy, Method method) throws NoSuchMethodException, ResourceException {
111 try {
112 proxy.endpoint.beforeDelivery(method);
113 } catch (NoSuchMethodException e) {
114 transition(proxy, DEAD);
115 throw e;
116 } catch (ResourceException e) {
117 transition(proxy, DEAD);
118 throw e;
119 }
120 }
121
122 public void onMessage(MessageEndpointProxy proxy, Message message) {
123 proxy.messageListener.onMessage(message);
124 }
125
126 public void afterDelivery(MessageEndpointProxy proxy) throws ResourceException {
127 try {
128 proxy.endpoint.afterDelivery();
129 } catch (ResourceException e) {
130 transition(proxy, DEAD);
131 throw e;
132 }
133 }
134
135 public void release(MessageEndpointProxy proxy) {
136 transition(proxy, DEAD);
137 }
138 }
139
140 private static class MessageEndpointDead extends MessageEndpointState {
141
142 protected void enter(MessageEndpointProxy proxy) {
143 proxy.endpoint.release();
144 }
145
146 public void beforeDelivery(MessageEndpointProxy proxy, Method method) throws NoSuchMethodException, ResourceException {
147 throw new InvalidMessageEndpointException();
148 }
149
150 public void onMessage(MessageEndpointProxy proxy, Message message) {
151 throw new InvalidMessageEndpointException();
152 }
153
154 public void afterDelivery(MessageEndpointProxy proxy) throws ResourceException {
155 throw new InvalidMessageEndpointException();
156 }
157
158 public void release(MessageEndpointProxy proxy) {
159 throw new InvalidMessageEndpointException();
160 }
161 }
162 }