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


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 need initialization before
21  * they can work.
22  *
23  * These classes rely also on an <code>InitableBroker</code> that
24  * ensures that there is only one instance of the class in the system,
25  * and handles dependencies between <code>Initables</code>.
26  *
27  * @author <a HREF="mailto:burton@apache.org">Kevin Burton</a>
28  * @author <a HREF="mailto:krzewski@e-point.pl">Rafal Krzewski</a>
29  * @version $Id: Initable.java,v 1.5.2.2 2004/05/20 03:05:18 seade Exp $
30  */
31 public interface Initable
32 {
33     /**
34      * Provides an Initable with a reference to the InitableBroker
35      * that instantiated this object, so that it can access other
36      * Initables.
37      *
38      * @param broker The InitableBroker that instantiated this object.
39      */
40     void setInitableBroker(InitableBroker broker);
41
42     /**
43      * Performs early initailization of an Initable
44      *
45      * During the startup of the system, different objects may be
46      * passed to your class using this method. It should ignore any
47      * objects that it doesn't need or understand.
48      *
49      * After the class changes its internal state so that getInit()
50      * returns true, this method will be called no more, and late
51      * initialization will not be performed.
52      *
53      * If your class relies on early initialization, and the object it
54      * expects was not received, you can use late initialization to
55      * throw an exception and complain.
56      *
57      * @param data An Object to use for initialization activities.
58      * @exception InitializationException if initilaization of this
59      * class was not successful.
60      */
61     void init(Object JavaDoc data) throws InitializationException;
62
63     /**
64      * Performs late initialization of an Initable.
65      *
66      * When your class is being requested from an InitableBroker, it
67      * will call getInit(), and if it returns false, this method will
68      * be invoked.
69      *
70      * @exception InitializationException if initialization of this
71      * class was not successful.
72      */
73     void init() throws InitializationException;
74
75     /**
76      * Returns an <code>Initable</code> to an uninitialized state.
77      *
78      * <p>This method must release all resources allocated by the
79      * <code>Initable</code> implementation, and resetting its internal state.
80      * You may chose to implement this operation or not. If you support
81      * this operation, getInit() should return false after successful
82      * shutdown of the service.
83      */
84     void shutdown();
85
86     /**
87      * Returns initialization status of an Initable.
88      *
89      * @return Initialization status of an Initable.
90      */
91     boolean getInit();
92 }
93
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