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Java > Open Source Codes > org > apache > avalon > meta > info > ServiceDescriptor


1 /*
2
3  ============================================================================
4                    The Apache Software License, Version 1.1
5  ============================================================================
6
7  Copyright (C) 1999-2002 The Apache Software Foundation. All rights reserved.
8
9  Redistribution and use in source and binary forms, with or without modifica-
10  tion, are permitted provided that the following conditions are met:
11
12  1. Redistributions of source code must retain the above copyright notice,
13     this list of conditions and the following disclaimer.
14
15  2. Redistributions in binary form must reproduce the above copyright notice,
16     this list of conditions and the following disclaimer in the documentation
17     and/or other materials provided with the distribution.
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19  3. The end-user documentation included with the redistribution, if any, must
20     include the following acknowledgment: "This product includes software
21     developed by the Apache Software Foundation (http://www.apache.org/)."
22     Alternately, this acknowledgment may appear in the software itself, if
23     and wherever such third-party acknowledgments normally appear.
24
25  4. The names "Jakarta", "Apache Avalon", "Avalon Framework" and
26     "Apache Software Foundation" must not be used to endorse or promote
27     products derived from this software without prior written
28     permission. For written permission, please contact apache@apache.org.
29
30  5. Products derived from this software may not be called "Apache", nor may
31     "Apache" appear in their name, without prior written permission of the
32     Apache Software Foundation.
33
34  THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED WARRANTIES,
35  INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND
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39  DING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
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45  This software consists of voluntary contributions made by many individuals
46  on behalf of the Apache Software Foundation. For more information on the
47  Apache Software Foundation, please see <http://www.apache.org/>.
48
49 */
50
51 package org.apache.avalon.meta.info;
52
53 import java.util.Properties JavaDoc;
54
55 /**
56  * This descriptor defines the type of service offerend or required
57  * by a component. The type corresponds to the class name of the
58  * class/interface implemented by component. Associated with each
59  * classname is a version object so that different versions of same
60  * interface can be represented.
61  *
62  * <p>Also associated with each service is a set of arbitrary
63  * attributes that can be used to store extra information
64  * about service. See {@link InfoDescriptor} for example
65  * of how to declare the container specific attributes.</p>
66  *
67  * <p>Possible uses for the attributes are to declare a service
68  * as "stateless", "pass-by-value", "remotable" or even to attach
69  * attributes such as security or transaction constraints. These
70  * attributes are container specific and should not be relied
71  * upon to work in all containers.</p>
72  *
73  * @author <a HREF="mailto:dev@avalon.apache.org">Avalon Development Team</a>
74  * @version $Revision: 1.4 $ $Date: 2003/07/12 13:34:27 $
75  */
76 public class ServiceDescriptor
77         extends Descriptor
78 {
79     /**
80      * The service reference that descriptor is describing.
81      */
82     private final ReferenceDescriptor m_designator;
83
84     /**
85      * Construct a service descriptor.
86      *
87      * @param descriptor the service descriptor
88      * @exception NullPointerException if the descriptor argument is null
89      */
90     public ServiceDescriptor( final ServiceDescriptor descriptor )
91             throws NullPointerException JavaDoc
92     {
93         super( descriptor.getProperties() );
94         m_designator = descriptor.getReference();
95     }
96
97
98     /**
99      * Construct a service descriptor for specified ReferenceDescriptor
100      *
101      * @param designator the service reference
102      * @exception NullPointerException if the designator argument is null
103      */
104     public ServiceDescriptor( final ReferenceDescriptor designator )
105             throws NullPointerException JavaDoc
106     {
107         this( designator, null );
108     }
109
110     /**
111      * Construct a service with specified name, version and attributes.
112      *
113      * @param designator the ReferenceDescriptor
114      * @param attributes the attributes of service
115      * @exception NullPointerException if the designator argument is null
116      */
117     public ServiceDescriptor( final ReferenceDescriptor designator,
118                               final Properties JavaDoc attributes )
119             throws NullPointerException JavaDoc
120     {
121         super( attributes );
122
123         if ( null == designator )
124         {
125             throw new NullPointerException JavaDoc( "designator" );
126         }
127
128         m_designator = designator;
129     }
130
131     /**
132      * Retrieve the reference that service descriptor refers to.
133      *
134      * @return the reference that service descriptor refers to.
135      */
136     public ReferenceDescriptor getReference()
137     {
138         return m_designator;
139     }
140
141     /**
142      * Return the cashcode for this instance.
143      * @return the instance hashcode
144      */
145     public int hashCode()
146     {
147         return m_designator.hashCode();
148     }
149
150    /**
151     * Test is the supplied object is equal to this object.
152     * @return true if the object are equivalent
153     */
154     public boolean equals(Object JavaDoc other)
155     {
156         boolean isEqual = super.equals( other ) && other instanceof ServiceDescriptor;
157         isEqual = isEqual && m_designator.equals( ( (ServiceDescriptor) other ).m_designator );
158         return isEqual;
159     }
160 }
161
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