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Java > Open Source Codes > org > apache > turbine > services > InitableBroker


1 package org.apache.turbine.services;
2
3 /*
4  * Copyright 2001-2004 The Apache Software Foundation.
5  *
6  * Licensed under the Apache License, Version 2.0 (the "License")
7  * you may not use this file except in compliance with the License.
8  * You may obtain a copy of the License at
9  *
10  * http://www.apache.org/licenses/LICENSE-2.0
11  *
12  * Unless required by applicable law or agreed to in writing, software
13  * distributed under the License is distributed on an "AS IS" BASIS,
14  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
15  * See the License for the specific language governing permissions and
16  * limitations under the License.
17  */
18
19 /**
20  * Classes that implement this interface can act as a broker for
21  * <code>Initable</code> classes.
22  *
23  * Functionality provided by the broker includes:
24  *
25  * <ul>
26  *
27  * <li>Maintaining a single instance of each <code>Initable</code> in
28  * the system.</li>
29  *
30  * <li>Early initialization of <code>Initables</code> during system
31  * startup.</li>
32  *
33  * <li>Late initialization of <code>Initables</code> before they are
34  * used.</li>
35  *
36  * <li>Providing instances of <code>Initables</code> to requesting
37  * parties.</li>
38  *
39  * <li>Maintainging dependencies between <code>Initables</code> during
40  * early initalization phases, including circular dependencies
41  * detection.</li>
42  *
43  * </ul>
44  *
45  * @author <a HREF="mailto:burton@apache.org">Kevin Burton</a>
46  * @author <a HREF="mailto:krzewski@e-point.pl">Rafal Krzewski</a>
47  * @version $Id: InitableBroker.java,v 1.5.2.2 2004/05/20 03:05:18 seade Exp $
48  */
49 public interface InitableBroker
50 {
51     /**
52      * Performs early initialization of an Initable class.
53      *
54      * If your class depends on another Initable being initialized to
55      * perform early initialization, you should always ask your broker
56      * to initialize the other class with the objects that are passed
57      * to you, before you try to retrieve that Initable's instance with
58      * getInitable().
59      *
60      * @param className The name of the class to be initailized.
61      * @param data An object to be used for initialization activities.
62      * @exception InitializationException if initialization of this
63      * class was not successful.
64      */
65     void initClass(String JavaDoc className, Object JavaDoc data)
66             throws InitializationException;
67
68     /**
69      * Shutdowns an Initable class.
70      *
71      * This method is used to release resources allocated by an
72      * Initable class, and return it to initial (uninitailized)
73      * state.
74      *
75      * @param className The name of the class to be uninitialized.
76      */
77     void shutdownClass(String JavaDoc className);
78
79     /**
80      * Provides an instance of Initable class ready to work.
81      *
82      * If the requested class couldn't be instatiated or initialized,
83      * InstantiationException will be thrown. You needn't handle this
84      * exception in your code, since it indicates fatal
85      * misconfigurtion of the system.
86      *
87      * @param className The name of the Initable requested.
88      * @return An instance of requested Initable.
89      * @exception InstantiationException if there was a problem
90      * during instantiation or initialization of the Initable.
91      */
92     Initable getInitable(String JavaDoc className) throws InstantiationException JavaDoc;
93 }
94
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