Instance


1   package org.eclipse.emf.examples.jet.article2.model;
2   
3   
4   import java.util.Iterator  ;
5   import java.util.Properties  ;
6   
7   
8   /**
9    * Class modelling an Singleton instance of an enumeration. An instance has a
10   * name, a set of attribute values, and knows whether it is the default instance
11   * of the enumeration.
12   * 
13   * @author Remko Popma
14   * @version $Revision: 1.1 $ ($Date: 2004/05/31 21:35:35 $)
15   */
16  public class Instance
17  {
18  
19    private TypesafeEnum mType = null;
20  
21    private String   mName = "";
22  
23    private Properties   mValues = new Properties  ();
24  
25    /**
26     * Creates an uninitialized <code>Instance</code>.
27     */
28    public Instance()
29    {
30    }
31  
32    /**
33     * Creates an <code>Instance</code> with the specified name.
34     * 
35     * @param name
36     *          the name of this instance
37     */
38    public Instance(String   name)
39    {
40      mName = name;
41    }
42  
43    /**
44     * Creates an <code>Instance</code> with the specified name and attribute
45     * values.
46     * 
47     * @param name
48     *          the name of this instance
49     * @param values
50     *          a <code>Properties</code> object mapping attribute names to the
51     *          attribute values for this instance
52     */
53    public Instance(String   name, Properties   values)
54    {
55      super();
56      mName = name;
57      mValues = values;
58    }
59  
60    /**
61     * Convenience method that returns a description of the key attribute names
62     * and values.
63     * 
64     * @return a comma-separated list of key attribute names and values, formatted
65     *         like
66     *         <code>attrib1-name = attrib1-value, attrib2-name = attrib2-value (, ...)</code>
67     * @throws IllegalStateException
68     *           if this instance has not been added to a type
69     */
70    public String   keyDescription()
71    {
72      assertTypeNotNull();
73  
74      StringBuffer   result = new StringBuffer  ();
75      for (Iterator   i = mType.keyAttributes(); i.hasNext();)
76      {
77        Attribute attribute = (Attribute)i.next();
78        result.append(attribute.getCappedName());
79        result.append(" = ");
80        result.append(getAttributeValue(attribute));
81        if (i.hasNext())
82        {
83          result.append(", ");
84        }
85      }
86      return result.toString();
87    }
88  
89    /**
90     * Convenience method that returns the attribute values of this instance, in
91     * the order expected by the constructor of this instance.
92     * 
93     * @return a comma-separated list of all attribute values of this instance,
94     *         formatted like <code>attrib1-value, attrib2-value (, ...)</code>
95     * @throws IllegalStateException
96     *           if this instance has not been added to a type
97     */
98    public String   constructorValues()
99    {
100     assertTypeNotNull(); // check we've been added to a TypesafeEnum
101 
102     StringBuffer   result = new StringBuffer  ();
103     for (Iterator   i = getType().attributes(); i.hasNext();)
104     {
105       Attribute attribute = (Attribute)i.next();
106       result.append(getAttributeValue(attribute));
107       if (i.hasNext())
108       {
109         result.append(", ");
110       }
111     }
112     return result.toString();
113   }
114 
115   /**
116    * Returns the name of this instance converted to a java class name. For
117    * example, a constant name like <code>THIS_IS_A_CONSTANT</code> is
118    * converted to <code>ThisIsAConstant</code>.
119    * 
120    * @return the name of this instance converted to a java class name
121    */
122   public String   getCappedName()
123   {
124     return NameUtil.constantToJavaClassName(getName());
125   }
126 
127   /**
128    * Returns the name of this instance.
129    * 
130    * @return the name of this instance
131    */
132   public String   getName()
133   {
134     return mName;
135   }
136 
137   /**
138    * Returns the <code>Properties</code> object mapping attribute names to the
139    * attribute values for this instance
140    * 
141    * @return the <code>Properties</code> object mapping attribute names to the
142    *         attribute values for this instance
143    */
144   public Properties   getValues()
145   {
146     return mValues;
147   }
148 
149   /**
150    * Returns the value of the specified attribute for this instance.
151    * 
152    * @param attribute
153    *          the attribute whose value to return
154    * @return the value of the specified attribute for this instance
155    */
156   public String   getAttributeValue(Attribute attribute)
157   {
158     return getAttributeValue(attribute.getName());
159   }
160 
161   /**
162    * Returns the value of the specified attribute for this instance.
163    * 
164    * @param attributeName
165    *          the name of the attribute whose value to return
166    * @return the value of the specified attribute for this instance
167    */
168   public String   getAttributeValue(String   attributeName)
169   {
170     return mValues.getProperty(attributeName);
171   }
172 
173   /**
174    * Sets the name of this instance.
175    * 
176    * @param name
177    *          the name of this instance
178    */
179   public void setName(String   name)
180   {
181     mName = name;
182   }
183 
184   /**
185    * Sets the <code>Properties</code> object mapping attribute names to the
186    * attribute values for this instance.
187    * 
188    * @param values
189    *          the <code>Properties</code> object mapping attribute names to
190    *          the attribute values for this instance
191    */
192   public void setValues(Properties   values)
193   {
194     mValues = values;
195   }
196 
197   /**
198    * Returns the <code>TypesafeEnum</code> parent for this instance.
199    * 
200    * @return the <code>TypesafeEnum</code> parent for this instance
201    */
202   public TypesafeEnum getType()
203   {
204     return mType;
205   }
206 
207   /**
208    * Sets the <code>TypesafeEnum</code> parent for this instance.
209    * 
210    * @param type
211    *          the <code>TypesafeEnum</code> parent for this instance
212    */
213   /* package */void setType(TypesafeEnum type)
214   {
215     mType = type;
216   }
217 
218   /**
219    * Returns whether this instance is the default instance of the parent
220    * <code>TypesafeEnum</code>.
221    * 
222    * @return whether this instance is the default instance of the parent
223    *         <code>TypesafeEnum</code>
224    * @throws IllegalStateException
225    *           if this instance has not been added to a type
226    */
227   public boolean isDefault()
228   {
229     assertTypeNotNull();
230     return getType().getDefaultInstance() == this;
231   }
232 
233   /**
234    * Sets whether this instance is the default instance of the parent
235    * <code>TypesafeEnum</code>.
236    * 
237    * @param isDefault
238    *          whether this instance is the default instance of the parent
239    *          <code>TypesafeEnum</code>
240    * @throws IllegalStateException
241    *           if this instance has not been added to a type
242    */
243   public void setDefault()
244   {
245     assertTypeNotNull();
246     getType().setDefaultInstance(this);
247   }
248 
249   private void assertTypeNotNull()
250   {
251     if (getType() == null)
252     {
253       throw new IllegalStateException  ("Type is null. This instance has not been added to a type yet.");
254     }
255   }
256 }
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