KickJava   Java API By Example, From Geeks To Geeks.

Java > Open Source Codes > org > apache > avalon > framework > component > Component


1 /* ====================================================================
2  * The Apache Software License, Version 1.1
3  *
4  * Copyright (c) 1997-2003 The Apache Software Foundation. All rights
5  * reserved.
6  *
7  * Redistribution and use in source and binary forms, with or without
8  * modification, are permitted provided that the following conditions
9  * are met:
10  *
11  * 1. Redistributions of source code must retain the above copyright
12  * notice, this list of conditions and the following disclaimer.
13  *
14  * 2. Redistributions in binary form must reproduce the above copyright
15  * notice, this list of conditions and the following disclaimer in
16  * the documentation and/or other materials provided with the
17  * distribution.
18  *
19  * 3. The end-user documentation included with the redistribution,
20  * if any, must include the following acknowledgment:
21  * "This product includes software developed by the
22  * Apache Software Foundation (http://www.apache.org/)."
23  * Alternately, this acknowledgment may appear in the software
24  * itself, if and wherever such third-party acknowledgments
25  * normally appear.
26  *
27  * 4. The names "Jakarta", "Avalon", and "Apache Software Foundation"
28  * must not be used to endorse or promote products derived from this
29  * software without prior written permission. For written
30  * permission, please contact apache@apache.org.
31  *
32  * 5. Products derived from this software may not be called "Apache",
33  * nor may "Apache" appear in their name, without prior written
34  * permission of the Apache Software Foundation.
35  *
36  * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED
37  * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
38  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
39  * DISCLAIMED. IN NO EVENT SHALL THE APACHE SOFTWARE FOUNDATION OR
40  * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
41  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
42  * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
43  * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
44  * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
45  * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
46  * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
47  * SUCH DAMAGE.
48  * ====================================================================
49  *
50  * This software consists of voluntary contributions made by many
51  * individuals on behalf of the Apache Software Foundation. For more
52  * information on the Apache Software Foundation, please see
53  * <http://www.apache.org/>.
54  */
55 package org.apache.avalon.framework.component;
56
57 /**
58  * This interface identifies classes that can be used as <code>Components</code>
59  * by a <code>Composable</code>.
60  *
61  * <p>
62  * The contract surrounding the <code>Component</code> is that it is
63  * used, but not a user. When a class implements this interface, it
64  * is stating that other entities may use that class.
65  * </p>
66  *
67  * <p>
68  * A <code>Component</code> is the basic building block of the Avalon Framework.
69  * When a class implements this interface, it allows itself to be
70  * managed by a <code>ComponentManager</code> and used by an outside
71  * element called a <code>Composable</code>. The <code>Composable</code>
72  * must know what type of <code>Component</code> it is accessing, so
73  * it will re-cast the <code>Component</code> into the type it needs.
74  * </p>
75  *
76  * <p>
77  * In order for a <code>Component</code> to be useful you must either
78  * extend this interface, or implement this interface in conjunction
79  * with one that actually has methods. The new interface is the contract
80  * with the <code>Composable</code> that this is a particular type of
81  * component, and as such it can perform those functions on that type
82  * of component.
83  * </p>
84  *
85  * <p>
86  * For example, we want a component that performs a logging function
87  * so we extend the <code>Component</code> to be a <code>LoggingComponent</code>.
88  * </p>
89  *
90  * <pre>
91  * interface LoggingComponent
92  * extends Component
93  * {
94  * log(String message);
95  * }
96  * </pre>
97  *
98  * <p>
99  * Now all <code>Composable</code>s that want to use this type of component,
100  * will re-cast the <code>Component</code> into a <code>LoggingComponent</code>
101  * and the <code>Composable</code> will be able to use the <code>log</code>
102  * method.
103  * </p>
104  *
105  * <p>
106  * <span style="color: red">Deprecated: </span><i>
107  * Deprecated without replacement. Should only be used while migrating away
108  * from a system based on Composable/ComponentManager. A generic <code>java.lang.Object</code>
109  * can be used as a replacement.
110  * </i>
111  * </p>
112  *
113  * @author <a HREF="mailto:dev@avalon.apache.org">Avalon Development Team</a>
114  * @version CVS $Revision: 1.14 $ $Date: 2003/02/11 15:58:38 $
115  */
116 public interface Component
117 {
118 }
119
Popular Tags