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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   * LongIdentity.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 long field.
30   * @version 2.0
31   */
32  public class LongIdentity extends SingleFieldIdentity {
33  	
34      /** The key.
35       */
36      private long key;
37  
38      private void construct(long key) {
39          this.key = key;
40          hashCode = hashClassName() ^ (int)key;
41      }
42  
43      /** Constructor with class and key.
44       * @param pcClass the class
45       * @param key the key
46       */
47      public LongIdentity (Class pcClass, long key) {
48          super (pcClass);
49          construct(key);
50      }
51  
52      /** Constructor with class and key.
53       * @param pcClass the class
54       * @param key the key
55       */
56      public LongIdentity (Class pcClass, Long key) {
57          super(pcClass);
58          setKeyAsObject(key);
59          construct(key.longValue());
60      }
61  
62      /** Constructor with class and key.
63       * @param pcClass the class
64       * @param str the key
65       */
66      public LongIdentity (Class pcClass, String str) {
67          super(pcClass);
68          assertKeyNotNull(str);
69          construct(Long.parseLong(str));
70      }
71  
72      /** Constructor only for Externalizable.
73       */
74      public LongIdentity () {
75      }
76  
77      /** Return the key.
78       * @return the key
79       */
80      public long getKey () {
81          return key;
82      }
83  
84      /** Return the String form of the key.
85       * @return the String form of the key
86       */
87      public String toString () {
88          return Long.toString(key);
89      }
90  
91      /** Determine if the other object represents the same object id.
92       * @param obj the other object
93       * @return true if both objects represent the same object id
94       */
95      public boolean equals (Object obj) {
96          if (this == obj) {
97              return true;
98          } else if (!super.equals (obj)) {
99              return false;
100         } else {
101             LongIdentity other = (LongIdentity) obj;
102             return key == other.key;
103         }
104     }
105 
106     /** Determine the ordering of identity objects.
107      * @param o Other identity
108      * @return The relative ordering between the objects
109      * @since 2.2
110      */
111     public int compareTo(Object o) {
112         if (o instanceof LongIdentity) {
113         	LongIdentity other = (LongIdentity)o;
114             int result = super.compare(other);
115             if (result == 0) {
116                 long diff = key - other.key;
117                 if (diff == 0) {
118                     return 0;
119                 } else {
120                     if (diff < 0) {
121                         return -1;
122                     } else {
123                         return 1;
124                     }
125                 }
126             } else {
127                 return result;
128             }
129         }
130         else if (o == null) {
131             throw new ClassCastException("object is null");
132         }
133         throw new ClassCastException(this.getClass().getName() + " != " + o.getClass().getName());
134     }
135 
136     /** Create the key as an Object.
137      * @return the key as an Object
138      * @since 2.0
139      */
140     protected Object createKeyAsObject() {
141         return new Long(key);
142     }
143 
144     /** Write this object. Write the superclass first.
145      * @param out the output
146      */
147     public void writeExternal(ObjectOutput out) throws IOException {
148         super.writeExternal (out);
149         out.writeLong(key);
150     }
151 
152     /** Read this object. Read the superclass first.
153      * @param in the input
154      */
155     public void readExternal(ObjectInput in)
156 		throws IOException, ClassNotFoundException {
157         super.readExternal (in);
158         key = in.readLong();
159     }
160 
161 }