KickJava   Java API By Example, From Geeks To Geeks.

Java > Open Source Codes > javax > jdo > identity > CharIdentity


1 /*
2  * Copyright 2005 The Apache Software Foundation.
3  *
4  * Licensed under the Apache License, Version 2.0 (the "License");
5  * you may not use this file except in compliance with the License.
6  * You may obtain a copy of the License at
7  *
8  * http://www.apache.org/licenses/LICENSE-2.0
9  *
10  * Unless required by applicable law or agreed to in writing, software
11  * distributed under the License is distributed on an "AS IS" BASIS,
12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13  * See the License for the specific language governing permissions and
14  * limitations under the License.
15  */
16
17 /*
18  * CharIdentity.java
19  *
20  */
21
22 package javax.jdo.identity;
23
24 import java.io.IOException JavaDoc;
25 import java.io.ObjectInput JavaDoc;
26 import java.io.ObjectOutput JavaDoc;
27
28 import javax.jdo.spi.I18NHelper;
29
30 /** This class is for identity with a single character field.
31  * @version 2.0
32  */
33 public class CharIdentity extends SingleFieldIdentity {
34
35     /** The Internationalization message helper.
36      */
37     private static I18NHelper msg = I18NHelper.getInstance ("javax.jdo.Bundle"); //NOI18N
38
39     /** The key.
40      */
41     private char key;
42
43     private void construct(char key) {
44         this.key = key;
45         hashCode = hashClassName() ^ key;
46     }
47
48     /** Constructor with class and key.
49      * @param pcClass the target class
50      * @param key the key
51      */
52     public CharIdentity (Class JavaDoc pcClass, char key) {
53         super (pcClass);
54         construct(key);
55     }
56
57     /** Constructor with class and key.
58      * @param pcClass the target class
59      * @param key the key
60      */
61     public CharIdentity (Class JavaDoc pcClass, Character JavaDoc key) {
62         super (pcClass);
63         setKeyAsObject(key);
64         construct(key.charValue());
65     }
66
67     /** Constructor with class and key. The String must have exactly one
68      * character.
69      * @param pcClass the target class
70      * @param str the key
71      */
72     public CharIdentity (Class JavaDoc pcClass, String JavaDoc str) {
73         super(pcClass);
74         assertKeyNotNull(str);
75         if (str.length() != 1)
76             throw new IllegalArgumentException JavaDoc(
77                 msg.msg("EXC_StringWrongLength")); //NOI18N
78 construct(str.charAt(0));
79     }
80
81     /** Constructor only for Externalizable.
82      */
83     public CharIdentity () {
84     }
85
86     /** Return the key.
87      * @return the key
88      */
89     public char getKey () {
90         return key;
91     }
92
93     /** Return the String form of the key.
94      * @return the String form of the key
95      */
96     public String JavaDoc toString () {
97         return Character.toString(key);
98     }
99
100     /** Determine if the other object represents the same object id.
101      * @param obj the other object
102      * @return true if both objects represent the same object id
103      */
104     public boolean equals (Object JavaDoc obj) {
105         if (this == obj) {
106             return true;
107         } else if (!super.equals (obj)) {
108             return false;
109         } else {
110             CharIdentity other = (CharIdentity) obj;
111             return key == other.key;
112         }
113     }
114
115     /** Create the key as an Object.
116      * @return the key as an Object
117      * @since 2.0
118      */
119     protected Object JavaDoc createKeyAsObject() {
120         return new Character JavaDoc(key);
121     }
122
123     /** Write this object. Write the superclass first.
124      * @param out the output
125      */
126     public void writeExternal(ObjectOutput JavaDoc out) throws IOException JavaDoc {
127         super.writeExternal (out);
128         out.writeChar(key);
129     }
130
131     /** Read this object. Read the superclass first.
132      * @param in the input
133      */
134     public void readExternal(ObjectInput JavaDoc in)
135         throws IOException JavaDoc, ClassNotFoundException JavaDoc {
136         super.readExternal (in);
137         key = in.readChar();
138     }
139     
140     private void computeHashCode() {
141         hashCode = hashClassName() ^ key;
142     }
143 }
144
Popular Tags