StringKey


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  /**
23   * This class can be used as an ObjectKey to uniquely identify an
24   * object within an application where the id  consists
25   * of a single entity such a GUID or the value of a db row's primary key.
26   *
27   * @author <a HREF="mailto:jmcnally@apache.org">John McNally</a>
28   * @version $Id: StringKey.java 473821 2006-11-11 22:37:25Z tv $
29   */
30  public class StringKey extends SimpleKey
31  {
32      /**
33       * Serial version
34       */
35      private static final long serialVersionUID = 5109588772086713341L;
36  
37      /**
38       * Creates an SimpleKey whose internal representation will be
39       * set later, through a set method
40       */
41      public StringKey()
42      {
43      }
44  
45      /**
46       * Creates a StringKey whose internal representation is a String
47       *
48       * @param key the key value
49       */
50      public StringKey(String   key)
51      {
52          this.key = key;
53      }
54  
55      /**
56       * Creates a StringKey that is equivalent to key.
57       *
58       * @param key the key value
59       */
60      public StringKey(StringKey key)
61      {
62          if (key != null)
63          {
64              this.key = key.getValue();
65          }
66          else
67          {
68              this.key = null;
69          }
70      }
71  
72      /**
73       * Sets the internal representation to a String
74       *
75       * @param key the key value
76       */
77      public void setValue(String   key)
78      {
79          this.key = key;
80      }
81  
82      /**
83       * Sets the internal representation to the same object used by key.
84       *
85       * @param key the key value
86       */
87      public void setValue(StringKey key)
88      {
89          if (key != null)
90          {
91              this.key = key.getValue();
92          }
93          else
94          {
95              this.key = null;
96          }
97      }
98  
99      /**
100      * Access the underlying String object.
101      *
102      * @return a <code>String</code> value
103      */
104     public String   getString()
105     {
106         return (String  ) key;
107     }
108 
109     /**
110      * keyObj is equal to this StringKey if keyObj is a StringKey or String
111      * that contains the same information this key contains.  Two ObjectKeys
112      * that both contain null values are not considered equal.
113      *
114      * @param keyObj the comparison value
115      * @return whether the two objects are equal
116      */
117     public boolean equals(Object   keyObj)
118     {
119         boolean isEqual = false;
120 
121         if (key != null)
122         {
123             if (keyObj instanceof String  )
124             {
125                 isEqual = keyObj.equals(key);
126             }
127             // check against a StringKey. Two keys are equal, if their
128             // internal keys equivalent.
129             else if (keyObj instanceof StringKey)
130             {
131                 Object   obj = ((StringKey) keyObj).getValue();
132                 isEqual =  key.equals(obj);
133             }
134         }
135         return isEqual;
136     }
137 
138     /**
139      * get a String representation
140      *
141      * @return a String representation of an empty String if the value is null
142      */
143     public String   toString()
144     {
145         if (key != null)
146         {
147             return (String  ) key;
148         }
149         return "";
150     }
151 }
152
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