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1
46
47 package org.mr.ra.inbound;
48
49 import org.apache.commons.logging.Log;
50 import org.apache.commons.logging.LogFactory;
51
52 import javax.jms.Message  ;
53 import javax.jms.MessageListener ;
54 import javax.resource.ResourceException ;
55 import javax.resource.spi.endpoint.MessageEndpoint ;
56 import java.lang.reflect.Method ;
57
58
61 public class MessageEndpointProxy implements MessageListener , MessageEndpoint {
62
63 private static final MessageEndpointState ALIVE = new MessageEndpointAlive();
64 private static final MessageEndpointState GOING_TO_DIE = new MessageEndpointInTheElectricChair();
65 private static final MessageEndpointState DEAD = new MessageEndpointDead();
66
67 private static final Log log = LogFactory.getLog(MessageEndpointProxy.class);
68
69 private static int proxyCount = 0;
70
71 private static int deliveryCount = 0;
72
73 private final int proxyID;
74
75 private MessageEndpoint endpoint;
76
77 private boolean alive = true;
78
79 private MessageEndpointState state = ALIVE;
80
81 private static int getID() {
82 return ++proxyCount;
83 }
84
85 private static int getNextDeliveryCount() {
86 return ++deliveryCount;
87 }
88
89
90 public MessageEndpointProxy(MessageEndpoint endpoint) {
91 if (!(endpoint instanceof MessageListener )) {
92 throw new IllegalArgumentException ("MessageEndpoint is not a MessageListener");
93 }
94 proxyID = getID();
95 this.endpoint = endpoint;
96 }
97
98 public void beforeDelivery(Method method) throws NoSuchMethodException , ResourceException {
99 state.beforeDelivery(this, method);
100 }
101
102 public void onMessage(Message message) {
103 state.onMessage(this, message);
105 }
106
107 public void afterDelivery() throws ResourceException {
108 state.afterDelivery(this);
109 }
110
111 public void release() {
112 state.release(this);
113 }
114
115 public String toString() {
116 return "MessageEndpointProxy{ " +
117 "proxyID: " + proxyID +
118 ", endpoint: " + endpoint +
119 " }";
120 }
121
122 private abstract static class MessageEndpointState {
123
124 public void beforeDelivery(MessageEndpointProxy proxy, Method method) throws NoSuchMethodException , ResourceException {
125 throw new IllegalStateException ();
126 }
127
128 public void onMessage(MessageEndpointProxy proxy, Message message) {
129 throw new IllegalStateException ();
130 }
131
132 public void afterDelivery(MessageEndpointProxy proxy) throws ResourceException {
133 throw new IllegalStateException ();
134 }
135
136 public void release(MessageEndpointProxy proxy) {
137 throw new IllegalStateException ();
138 }
139
140 protected final void transition(MessageEndpointProxy proxy, MessageEndpointState nextState) {
141 proxy.state = nextState;
142 nextState.enter(proxy);
143 }
144
145 protected void enter(MessageEndpointProxy proxy) {
146 }
147 }
148
149 private static class MessageEndpointAlive extends MessageEndpointState {
150
151 public void beforeDelivery(MessageEndpointProxy proxy, Method method) throws NoSuchMethodException , ResourceException {
152 try {
153 proxy.endpoint.beforeDelivery(method);
154 } catch (NoSuchMethodException e) {
155 transition(proxy, DEAD);
156 throw e;
157 } catch (ResourceException e) {
158 transition(proxy, DEAD);
159 throw e;
160 }
161 }
162
163 public void onMessage(MessageEndpointProxy proxy, Message message) {
164 try {
165 ((MessageListener ) proxy.endpoint).onMessage(message);
166 } catch (RuntimeException e) {
167 transition(proxy, GOING_TO_DIE);
168 throw e;
169 }
170 }
171
172 public void afterDelivery(MessageEndpointProxy proxy) throws ResourceException {
173 try {
174 proxy.endpoint.afterDelivery();
175 } catch (ResourceException e) {
176 transition(proxy, DEAD);
177 throw e;
178 }
179 }
180
181 public void release(MessageEndpointProxy proxy) {
182 transition(proxy, DEAD);
183 }
184 }
185
186 private static class MessageEndpointInTheElectricChair extends MessageEndpointState {
187
188 public void afterDelivery(MessageEndpointProxy proxy) throws ResourceException {
189 try {
190 proxy.endpoint.afterDelivery();
191 } catch (ResourceException e) {
192 throw e;
193 } finally {
194 transition(proxy, DEAD);
195 }
196 }
197
198 public void release(MessageEndpointProxy proxy) {
199 transition(proxy, DEAD);
200 }
201 }
202
203 private static class MessageEndpointDead extends MessageEndpointState {
204
205 protected void enter(MessageEndpointProxy proxy) {
206 proxy.endpoint.release();
207 proxy.endpoint = null;
208 }
209
210 public void beforeDelivery(MessageEndpointProxy proxy, Method method) throws NoSuchMethodException , ResourceException {
211 throw new InvalidMessageEndpointException();
212 }
213
214 public void onMessage(MessageEndpointProxy proxy, Message message) {
215 throw new InvalidMessageEndpointException();
216 }
217
218 public void afterDelivery(MessageEndpointProxy proxy) throws ResourceException {
219 throw new InvalidMessageEndpointException();
220 }
221
222 public void release(MessageEndpointProxy proxy) {
223 throw new InvalidMessageEndpointException();
224 }
225 }
226 }
227 |
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