KickJava   Java API By Example, From Geeks To Geeks.

Java > Open Source Codes > jegg > EggBase


1 /*
2  * Copyright (c) 2004, Bruce Lowery
3  * All rights reserved.
4  *
5  * Redistribution and use in source and binary forms, with or without
6  * modification, are permitted provided that the following conditions are met:
7  *
8  * - Redistributions of source code must retain the above copyright notice,
9  * this list of conditions and the following disclaimer.
10  * - Redistributions in binary form must reproduce the above copyright
11  * notice, this list of conditions and the following disclaimer in the
12  * documentation and/or other materials provided with the distribution.
13  * - Neither the name of GOSSIP nor the names of its contributors may be used
14  * to endorse or promote products derived from this software without
15  * specific prior written permission.
16  *
17  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
18  * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
19  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
20  * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
21  * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
22  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
23  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
24  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
25  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
26  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
27  * POSSIBILITY OF SUCH DAMAGE.
28  */
29 package jegg;
30
31
32 /**
33  * A convenience base class for a concrete egg implementation. Rather
34  * than directly implement the jegg.Egg interface, an application egg can
35  * extend this base class.
36  * <p>
37  * This class handles the context configuration from the JEgg framework
38  * and makes the context available to the derived class via a getter method,
39  * and provides a default implementation of the <code>init</code> method that
40  * the framework calls to complete the initialization of the egg, prior to
41  * delivering the first application message to the egg.
42  * </p>
43  * <p>
44  * For each message type that the derived class can handle, it should
45  * include a method of the following form:
46  * <pre>
47  * public void handle([message-type]);
48  * </pre>
49  * where [message-type] is the concrete class name of the message type that
50  * method can handle. All handler methods should follow this naming
51  * convention - it's expected by the message dispatcher.
52  * </p>
53  */
54 public abstract class EggBase implements Egg
55 {
56     /** The egg's context instance. */
57     private EggContext _context;
58     
59     /*
60      * (non-Javadoc)
61      * @see jegg.Egg#setContext(jegg.EggContext)
62      */
63     public final void setContext(final EggContext c) {_context = c;}
64     
65     /**
66      * A default implementation, that does nothing, of the initialization
67      * method used by the framework to complete the initialization of the
68      * derived class egg.
69      */
70     public void init() throws UnableToInitializeException { /*OVERRIDE IN SUBCLASS*/ }
71     
72     /**
73      * Return this egg's current context.
74      */
75     protected final EggContext getContext() { return _context;}
76     
77     /**
78      * Return this egg's message port.
79      * @return this egg's message port.
80      */
81     protected Port getPort() { return getContext().getPort();}
82 }
83
Popular Tags