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Java > Open Source Codes > org > apache > ojb > broker > metadata > DescriptorBase


1 package org.apache.ojb.broker.metadata;
2
3 /* Copyright 2002-2005 The Apache Software Foundation
4  *
5  * Licensed under the Apache License, Version 2.0 (the "License");
6  * you may not use this file except in compliance with the License.
7  * You may obtain a copy of the License at
8  *
9  * http://www.apache.org/licenses/LICENSE-2.0
10  *
11  * Unless required by applicable law or agreed to in writing, software
12  * distributed under the License is distributed on an "AS IS" BASIS,
13  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
14  * See the License for the specific language governing permissions and
15  * limitations under the License.
16  */
17
18 import java.io.Serializable JavaDoc;
19 import java.util.*;
20
21 /**
22  * base class for all Descriptors. It is used to implement the AttributeContainer
23  * interface which provides mechanics for user defined attributes.
24  * @author Thomas Mahler
25  */
26 class DescriptorBase implements AttributeContainer, Serializable JavaDoc
27 {
28     static final long serialVersionUID = 713914612744155925L;
29     /** holds user defined attributes */
30     private Map attributeMap = null;
31
32     /**
33      * Constructor for DescriptorBase.
34      */
35     public DescriptorBase()
36     {
37     }
38
39     /**
40      * @see org.apache.ojb.broker.metadata.AttributeContainer#addAttribute(String, String)
41      */
42     public void addAttribute(String JavaDoc attributeName, String JavaDoc attributeValue)
43     {
44         // Don't allow null attribute names.
45 if (attributeName == null)
46         {
47             return;
48         }
49         // Set up the attribute list
50 if (attributeMap == null)
51         {
52             attributeMap = new HashMap();
53         }
54         // Add the entry.
55 attributeMap.put(attributeName, attributeValue);
56     }
57
58     /**
59      * @see org.apache.ojb.broker.metadata.AttributeContainer#getAttribute(String, String)
60      */
61     public String JavaDoc getAttribute(String JavaDoc attributeName, String JavaDoc defaultValue)
62     {
63         String JavaDoc result = defaultValue;
64         if (attributeMap != null)
65         {
66             result = (String JavaDoc) attributeMap.get(attributeName);
67             if (result == null)
68             {
69                 result = defaultValue;
70             }
71         }
72         return result;
73     }
74
75     /**
76      * @see org.apache.ojb.broker.metadata.AttributeContainer#getAttribute(String)
77      */
78     public String JavaDoc getAttribute(String JavaDoc attributeName)
79     {
80         return this.getAttribute(attributeName, null);
81     }
82
83     /**
84      * Returns the attribute map (name, value) of this descriptor. Note that the
85      * returned map is not modifiable.
86      *
87      * @return The attributes
88      */
89     public Map getAttributes()
90     {
91         return Collections.unmodifiableMap(attributeMap);
92     }
93
94     /**
95      * Returns an array of the names of all atributes of this descriptor.
96      *
97      * @return The list of attribute names (will not be <code>null</code>)
98      */
99     public String JavaDoc[] getAttributeNames()
100     {
101         Set keys = (attributeMap == null ? new HashSet() : attributeMap.keySet());
102         String JavaDoc[] result = new String JavaDoc[keys.size()];
103
104         keys.toArray(result);
105         return result;
106     }
107     
108     public String JavaDoc toString()
109     {
110         StringBuffer JavaDoc buf = new StringBuffer JavaDoc();
111         buf.append("custom attributes [");
112         buf.append(attributeMap);
113         buf.append("]");
114         return buf.toString();
115     }
116 }
117
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