StaticLabeledEnum


1   /*
2    * Copyright 2002-2006 the original author or authors.
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  package org.springframework.core.enums;
18  
19  /**
20   * Base class for static type-safe labeled enum instances.
21   * 
22   * Usage example:
23   * 
24   * <pre>
25   * public class FlowSessionStatus extends StaticLabeledEnum {
26   *
27   *     // public static final instances!
28   *     public static FlowSessionStatus CREATED = new FlowSessionStatus(0, &quot;Created&quot;);
29   *     public static FlowSessionStatus ACTIVE = new FlowSessionStatus(1, &quot;Active&quot;);
30   *     public static FlowSessionStatus PAUSED = new FlowSessionStatus(2, &quot;Paused&quot;);
31   *     public static FlowSessionStatus SUSPENDED = new FlowSessionStatus(3, &quot;Suspended&quot;);
32   *     public static FlowSessionStatus ENDED = new FlowSessionStatus(4, &quot;Ended&quot;);
33   *     
34   *     // private constructor!
35   *     private FlowSessionStatus(int code, String label) {
36   *         super(code, label);
37   *     }
38   *     
39   *     // custom behavior
40   * }</pre>
41   * 
42   * @author Keith Donald
43   * @since 1.2.6
44   */
45  public abstract class StaticLabeledEnum extends AbstractLabeledEnum {
46  
47      /**
48       * The unique code of the enum.
49       */
50      private final Short   code;
51  
52      /**
53       * A descriptive label for the enum.
54       */
55      private final transient String   label;
56  
57  
58      /**
59       * Create a new StaticLabeledEnum instance.
60       * @param code the short code
61       * @param label the label (can be <code>null</code>)
62       */
63      protected StaticLabeledEnum(int code, String   label) {
64          this.code = new Short  ((short) code);
65          if (label != null) {
66              this.label = label;
67          }
68          else {
69              this.label = this.code.toString();
70          }
71      }
72  
73      public Comparable   getCode() {
74          return code;
75      }
76  
77      public String   getLabel() {
78          return label;
79      }
80  
81      /**
82       * Return the code of this LabeledEnum instance as a short.
83       */
84      public short shortValue() {
85          return ((Number  ) getCode()).shortValue();
86      }
87  
88  
89      //---------------------------------------------------------------------
90      // Serialization support
91      //---------------------------------------------------------------------
92  
93      /**
94       * Return the resolved type safe static enum instance.
95       */
96      protected Object   readResolve() {
97          return StaticLabeledEnumResolver.instance().getLabeledEnumByCode(getType(), getCode());
98      }
99  
100 }
101
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