01: package org.apache.turbine.services;
02:
03: /*
04: * Copyright 2001-2005 The Apache Software Foundation.
05: *
06: * Licensed under the Apache License, Version 2.0 (the "License")
07: * you may not use this file except in compliance with the License.
08: * You may obtain a copy of the License at
09: *
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 264148 2005-08-29 14:21:04Z henning $
30: */
31: public interface Initable {
32: /**
33: * Provides an Initable with a reference to the InitableBroker
34: * that instantiated this object, so that it can access other
35: * Initables.
36: *
37: * @param broker The InitableBroker that instantiated this object.
38: */
39: void setInitableBroker(InitableBroker broker);
40:
41: /**
42: * Performs early initailization of an Initable
43: *
44: * During the startup of the system, different objects may be
45: * passed to your class using this method. It should ignore any
46: * objects that it doesn't need or understand.
47: *
48: * After the class changes its internal state so that getInit()
49: * returns true, this method will be called no more, and late
50: * initialization will not be performed.
51: *
52: * If your class relies on early initialization, and the object it
53: * expects was not received, you can use late initialization to
54: * throw an exception and complain.
55: *
56: * @param data An Object to use for initialization activities.
57: * @exception InitializationException if initilaization of this
58: * class was not successful.
59: */
60: void init(Object data) throws InitializationException;
61:
62: /**
63: * Performs late initialization of an Initable.
64: *
65: * When your class is being requested from an InitableBroker, it
66: * will call getInit(), and if it returns false, this method will
67: * be invoked.
68: *
69: * @exception InitializationException if initialization of this
70: * class was not successful.
71: */
72: void init() throws InitializationException;
73:
74: /**
75: * Returns an <code>Initable</code> to an uninitialized state.
76: *
77: * <p>This method must release all resources allocated by the
78: * <code>Initable</code> implementation, and resetting its internal state.
79: * You may chose to implement this operation or not. If you support
80: * this operation, getInit() should return false after successful
81: * shutdown of the service.
82: */
83: void shutdown();
84:
85: /**
86: * Returns initialization status of an Initable.
87: *
88: * @return Initialization status of an Initable.
89: */
90: boolean getInit();
91: }
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