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Java > Open Source Codes > org > apache > cayenne > remote > BaseConnection


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19
20 package org.apache.cayenne.remote;
21
22 import org.apache.commons.logging.Log;
23 import org.apache.commons.logging.LogFactory;
24 import org.apache.cayenne.CayenneRuntimeException;
25
26 /**
27  * A common base class for concrete ClientConnection implementations. Provides message
28  * logging functionality via commons-logging.
29  *
30  * @since 1.2
31  * @author Andrus Adamchik
32  */
33 public abstract class BaseConnection implements ClientConnection {
34
35     protected Log logger;
36     protected long messageId;
37
38     /**
39      * Default constructor that initializes logging and a single threaded EventManager.
40      */
41     protected BaseConnection() {
42         this.logger = LogFactory.getLog(getClass());
43     }
44
45     /**
46      * Invokes 'beforeSendMessage' on self, then invokes 'doSendMessage'. Implements basic
47      * logging functionality. Do not override this method unless absolutely necessary.
48      * Override 'beforeSendMessage' and 'doSendMessage' instead.
49      */
50     public Object JavaDoc sendMessage(ClientMessage message) throws CayenneRuntimeException {
51         if (message == null) {
52             throw new NullPointerException JavaDoc("Null message");
53         }
54
55         beforeSendMessage(message);
56
57         // log start...
58 long t0 = 0;
59         String JavaDoc messageLabel = "";
60
61         // using sequential number for message id ... it can be useful for some basic
62 // connector stats.
63 long messageId = this.messageId++;
64
65         if (logger.isInfoEnabled()) {
66             t0 = System.currentTimeMillis();
67             messageLabel = message.toString();
68             logger.info("--- Message " + messageId + ": " + messageLabel);
69         }
70
71         Object JavaDoc response;
72         try {
73             response = doSendMessage(message);
74         }
75         catch (CayenneRuntimeException e) {
76
77             // log error
78 if (logger.isInfoEnabled()) {
79                 long time = System.currentTimeMillis() - t0;
80                 logger.info("*** Message error for "
81                         + messageId
82                         + ": "
83                         + messageLabel
84                         + " - took "
85                         + time
86                         + " ms.");
87             }
88
89             throw e;
90         }
91
92         // log success...
93 if (logger.isInfoEnabled()) {
94             long time = System.currentTimeMillis() - t0;
95             logger.info("=== Message "
96                     + messageId
97                     + ": "
98                     + messageLabel
99                     + " done - took "
100                     + time
101                     + " ms.");
102         }
103
104         return response;
105     }
106
107     /**
108      * Returns a count of processed messages since the beginning of life of this
109      * connector.
110      */
111     public long getProcessedMessagesCount() {
112         return messageId + 1;
113     }
114
115     /**
116      * Called before logging the beginning of message processing.
117      */
118     protected abstract void beforeSendMessage(ClientMessage message)
119             throws CayenneRuntimeException;
120
121     /**
122      * The worker method invoked to process message.
123      */
124     protected abstract Object JavaDoc doSendMessage(ClientMessage message)
125             throws CayenneRuntimeException;
126 }
127
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