View Javadoc

1   /*
2    * Licensed to the Apache Software Foundation (ASF) under one or more
3    * contributor license agreements.  See the NOTICE file distributed with
4    * this work for additional information regarding copyright ownership.
5    * The ASF licenses this file to You under the Apache License, Version 2.0
6    * (the "License"); you may not use this file except in compliance with
7    * the License.  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  /*
19   * IntIdentity.java
20   *
21   */
22   
23  package javax.jdo.identity;
24  
25  import java.io.IOException;
26  import java.io.ObjectInput;
27  import java.io.ObjectOutput;
28  
29  /** This class is for identity with a single int field.
30   * @version 2.0
31   */
32  public class IntIdentity extends SingleFieldIdentity {
33  
34      private int key;
35  
36      private void construct(int key) {
37          this.key = key;
38          hashCode = hashClassName() ^ key;
39      }
40  
41      /** Constructor with class and key.
42       * @param pcClass the class
43       * @param key the key
44       */
45      public IntIdentity (Class pcClass, int key) {
46          super(pcClass);
47          construct(key);
48  	}
49  
50      /** Constructor with class and key.
51       * @param pcClass the class
52       * @param key the key
53       */
54      public IntIdentity (Class pcClass, Integer key) {
55          super(pcClass);
56          setKeyAsObject(key);
57          construct(key.intValue ());
58      }
59  
60  
61      /** Constructor with class and key.
62       * @param pcClass the class
63       * @param str the key
64       */
65      public IntIdentity (Class pcClass, String str) {
66          super(pcClass);
67          assertKeyNotNull(str);
68          construct(Integer.parseInt(str));
69      }
70  
71      /** Constructor only for Externalizable.
72       */
73      public IntIdentity () {
74      }
75  
76      /** Return the key.
77       * @return the key
78       */
79      public int getKey () {
80          return key;
81      }
82  
83      /** Return the String form of the key.
84       * @return the String form of the key
85       */
86      public String toString () {
87          return Integer.toString(key);
88      }
89  
90      /** Determine if the other object represents the same object id.
91       * @param obj the other object
92       * @return true if both objects represent the same object id
93       */
94      public boolean equals (Object obj) {
95          if (this == obj) {
96              return true;
97          } else if (!super.equals (obj)) {
98              return false;
99          } else {
100             IntIdentity other = (IntIdentity) obj;
101             return key == other.key;
102         }
103     }
104 
105     /** Determine the ordering of identity objects.
106      * @param o Other identity
107      * @return The relative ordering between the objects
108      * @since 2.2
109      */
110     public int compareTo(Object o) {
111         if (o instanceof IntIdentity) {
112         	IntIdentity other = (IntIdentity)o;
113             int result = super.compare(other);
114             if (result == 0) {
115                 return (key - other.key);
116             } else {
117                 return result;
118             }
119         }
120        else if (o == null) {
121             throw new ClassCastException("object is null");
122         }
123         throw new ClassCastException(this.getClass().getName() + " != " + o.getClass().getName());
124     }
125 
126     /** Create the key as an Object.
127      * @return the key as an Object
128      * @since 2.0
129      */
130     protected Object createKeyAsObject() {
131         return new Integer(key);
132     }
133 
134     /** Write this object. Write the superclass first.
135      * @param out the output
136      */
137     public void writeExternal(ObjectOutput out) throws IOException {
138         super.writeExternal (out);
139         out.writeInt(key);
140     }
141 
142     /** Read this object. Read the superclass first.
143      * @param in the input
144      */
145     public void readExternal(ObjectInput in)
146 		throws IOException, ClassNotFoundException {
147         super.readExternal (in);
148         key = in.readInt();
149     }
150 }