DateKey


1   package org.apache.torque.om;
2   
3   /*
4    * Licensed to the Apache Software Foundation (ASF) under one
5    * or more contributor license agreements.  See the NOTICE file
6    * distributed with this work for additional information
7    * regarding copyright ownership.  The ASF licenses this file
8    * to you under the Apache License, Version 2.0 (the
9    * "License"); you may not use this file except in compliance
10   * with the License.  You may obtain a copy of the License at
11   *
12   *   http://www.apache.org/licenses/LICENSE-2.0
13   *
14   * Unless required by applicable law or agreed to in writing,
15   * software distributed under the License is distributed on an
16   * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
17   * KIND, either express or implied.  See the License for the
18   * specific language governing permissions and limitations
19   * under the License.
20   */
21  
22  import java.util.Date  ;
23  
24  /**
25   * This class can be used as an ObjectKey to uniquely identify an
26   * object within an application where the id is a Date.
27   *
28   * @author <a HREF="mailto:jmcnally@apache.org">John McNally</a>
29   * @version $Id: DateKey.java 476550 2006-11-18 16:08:37Z tfischer $
30   */
31  public class DateKey extends SimpleKey
32  {
33      /**
34       * Serial version
35       */
36      private static final long serialVersionUID = 3102583536685348517L;
37  
38      /**
39       * Creates an DateKey whose internal representation will be
40       * set later, through a set method
41       */
42      public DateKey()
43      {
44      }
45  
46      /**
47       * Creates a DateKey whose internal representation is a Date
48       * given by the long number given by the String
49       *
50       * @param key the key value
51       * @throws NumberFormatException if key is not valid
52       */
53      public DateKey(String   key)
54      {
55          this.key = new Date  (Long.parseLong(key));
56      }
57  
58      /**
59       * Creates a DateKey
60       *
61       * @param key the key value
62       */
63      public DateKey(Date   key)
64      {
65          this.key = key;
66      }
67  
68      /**
69       * Creates a DateKey that is equivalent to key.
70       *
71       * @param key the key value
72       */
73      public DateKey(DateKey key)
74      {
75          if (key != null)
76          {
77              this.key = key.getValue();
78          }
79          else
80          {
81              this.key = null;
82          }
83      }
84  
85      /**
86       * Sets the internal representation to a String
87       *
88       * @param key the key value
89       */
90      public void setValue(String   key)
91      {
92          this.key = new Date  (Long.parseLong(key));
93      }
94  
95      /**
96       * Sets the internal representation to the same object used by key.
97       *
98       * @param key the key value
99       */
100     public void setValue(DateKey key)
101     {
102         if (key != null)
103         {
104             this.key = key.getValue();
105         }
106         else
107         {
108             this.key = null;
109         }
110     }
111 
112     /**
113      * Access the underlying Date object.
114      *
115      * @return a <code>Date</code> value
116      */
117     public Date   getDate()
118     {
119         return (Date  ) key;
120     }
121 
122     /**
123      * keyObj is equal to this DateKey if keyObj is a DateKey or String
124      * that contains the same information this key contains.  Two ObjectKeys
125      * that both contain null values are not considered equal.
126      *
127      * @param keyObj the comparison value
128      * @return whether the two objects are equal
129      */
130     public boolean equals(Object   keyObj)
131     {
132         boolean isEqual = false;
133 
134         if (key != null)
135         {
136             if (keyObj instanceof String  )
137             {
138                 isEqual =  toString().equals(keyObj);
139             }
140             // check against a DateKey. Two keys are equal, if their
141             // internal keys equivalent.
142             else if (keyObj instanceof DateKey)
143             {
144                 Object   obj = ((DateKey) keyObj).getValue();
145                 isEqual =  key.equals(obj);
146             }
147         }
148         return isEqual;
149     }
150 
151     /**
152      * get a String representation
153      *
154      * @return a String representation of the Date or an empty String if the
155      *          Date is null
156      */
157     public String   toString()
158     {
159         Date   dt = getDate();
160         return (dt == null ? "" : Long.toString(dt.getTime()));
161     }
162 }
163
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