|
1
18 package org.apache.activemq.ra;
19
20 import java.lang.reflect.Method  ;
21
22 import javax.jms.Message ;
23 import javax.jms.MessageListener ;
24 import javax.resource.ResourceException ;
25 import javax.resource.spi.endpoint.MessageEndpoint ;
26
27
30 public class MessageEndpointProxy implements MessageListener , MessageEndpoint {
31
32 private static final MessageEndpointState ALIVE = new MessageEndpointAlive();
33 private static final MessageEndpointState DEAD = new MessageEndpointDead();
34
35
36 private static int proxyCount = 0;
37 private final int proxyID;
38
39 private final MessageEndpoint endpoint;
40 private final MessageListener messageListener;
41 private MessageEndpointState state = ALIVE;
42
43 private static int getID() {
44 return ++proxyCount;
45 }
46
47 public MessageEndpointProxy(MessageEndpoint endpoint) {
48 if (!(endpoint instanceof MessageListener )) {
49 throw new IllegalArgumentException ("MessageEndpoint is not a MessageListener");
50 }
51 messageListener = (MessageListener ) endpoint;
52 proxyID = getID();
53 this.endpoint = endpoint;
54 }
55
56 public void beforeDelivery(Method method) throws NoSuchMethodException , ResourceException {
57 state.beforeDelivery(this, method);
58 }
59
60 public void onMessage(Message message) {
61 state.onMessage(this, message);
62 }
63
64 public void afterDelivery() throws ResourceException {
65 state.afterDelivery(this);
66 }
67
68 public void release() {
69 state.release(this);
70 }
71
72 public String toString() {
73 return "MessageEndpointProxy{ " +
74 "proxyID: " + proxyID +
75 ", endpoint: " + endpoint +
76 " }";
77 }
78
79 private abstract static class MessageEndpointState {
80
81 public void beforeDelivery(MessageEndpointProxy proxy, Method method) throws NoSuchMethodException , ResourceException {
82 throw new IllegalStateException ();
83 }
84
85 public void onMessage(MessageEndpointProxy proxy, Message message) {
86 throw new IllegalStateException ();
87 }
88
89 public void afterDelivery(MessageEndpointProxy proxy) throws ResourceException {
90 throw new IllegalStateException ();
91 }
92
93 public void release(MessageEndpointProxy proxy) {
94 throw new IllegalStateException ();
95 }
96
97 protected final void transition(MessageEndpointProxy proxy, MessageEndpointState nextState) {
98 proxy.state = nextState;
99 nextState.enter(proxy);
100 }
101
102 protected void enter(MessageEndpointProxy proxy) {
103 }
104 }
105
106 private static class MessageEndpointAlive extends MessageEndpointState {
107
108 public void beforeDelivery(MessageEndpointProxy proxy, Method method) throws NoSuchMethodException , ResourceException {
109 try {
110 proxy.endpoint.beforeDelivery(method);
111 } catch (NoSuchMethodException e) {
112 transition(proxy, DEAD);
113 throw e;
114 } catch (ResourceException e) {
115 transition(proxy, DEAD);
116 throw e;
117 }
118 }
119
120 public void onMessage(MessageEndpointProxy proxy, Message message) {
121 proxy.messageListener.onMessage(message);
122 }
123
124 public void afterDelivery(MessageEndpointProxy proxy) throws ResourceException {
125 try {
126 proxy.endpoint.afterDelivery();
127 } catch (ResourceException e) {
128 transition(proxy, DEAD);
129 throw e;
130 }
131 }
132
133 public void release(MessageEndpointProxy proxy) {
134 transition(proxy, DEAD);
135 }
136 }
137
138 private static class MessageEndpointDead extends MessageEndpointState {
139
140 protected void enter(MessageEndpointProxy proxy) {
141 proxy.endpoint.release();
142 }
143
144 public void beforeDelivery(MessageEndpointProxy proxy, Method method) throws NoSuchMethodException , ResourceException {
145 throw new InvalidMessageEndpointException();
146 }
147
148 public void onMessage(MessageEndpointProxy proxy, Message message) {
149 throw new InvalidMessageEndpointException();
150 }
151
152 public void afterDelivery(MessageEndpointProxy proxy) throws ResourceException {
153 throw new InvalidMessageEndpointException();
154 }
155
156 public void release(MessageEndpointProxy proxy) {
157 throw new InvalidMessageEndpointException();
158 }
159 }
160 }
161 |
Popular Tags |
Java API By Example, From Geeks To Geeks.