SpinnerListModel


1   /*
2    * @(#)SpinnerListModel.java    1.11 04/05/05
3    *
4    * Copyright 2004 Sun Microsystems, Inc. All rights reserved.
5    * SUN PROPRIETARY/CONFIDENTIAL. Use is subject to license terms.
6    */
7   
8   package javax.swing;
9   
10  import java.util.*;
11  import java.io.Serializable  ;
12  
13  
14  /** 
15   * A simple implementation of <code>SpinnerModel</code> whose
16   * values are defined by an array or a <code>List</code>.
17   * For example to create a model defined by 
18   * an array of the names of the days of the week:
19   * <pre>
20   * String[] days = new DateFormatSymbols().getWeekdays();
21   * SpinnerModel model = new SpinnerListModel(Arrays.asList(days).subList(1, 8));
22   * </pre>
23   * This class only stores a reference to the array or <code>List</code>
24   * so if an element of the underlying sequence changes, it's up 
25   * to the application to notify the <code>ChangeListeners</code> by calling
26   * <code>fireStateChanged</code>.  
27   * <p>
28   * This model inherits a <code>ChangeListener</code>.  
29   * The <code>ChangeListener</code>s are notified whenever the
30   * model's <code>value</code> or <code>list</code> properties changes.
31   * 
32   * @see JSpinner
33   * @see SpinnerModel
34   * @see AbstractSpinnerModel
35   * @see SpinnerNumberModel
36   * @see SpinnerDateModel
37   * 
38   * @version 1.11 05/05/04
39   * @author Hans Muller
40   * @since 1.4
41   */
42  public class SpinnerListModel extends AbstractSpinnerModel   implements Serializable  
43  {
44      private List list;
45      private int index;
46  
47  
48      /**
49       * Constructs a <code>SpinnerModel</code> whose sequence of
50       * values is defined by the specified <code>List</code>. 
51       * The initial value (<i>current element</i>)
52       * of the model will be <code>values.get(0)</code>. 
53       * If <code>values</code> is <code>null</code> or has zero
54       * size, an <code>IllegalArugmentException</code> is thrown.
55       * 
56       * @param values the sequence this model represents
57       * @throws IllegalArugmentException if <code>values</code> is
58       *    <code>null</code> or zero size
59       */
60      public SpinnerListModel(List<?> values) {
61          if (values == null || values.size() == 0) {
62              throw new IllegalArgumentException  ("SpinnerListModel(List) expects non-null non-empty List");
63          }
64      this.list = values;
65      this.index = 0;
66      }
67  
68  
69      /**
70       * Constructs a <code>SpinnerModel</code> whose sequence of values
71       * is defined by the specified array.  The initial value of the model 
72       * will be <code>values[0]</code>.  If <code>values</code> is 
73       * <code>null</code> or has zero length, an
74       * <code>IllegalArugmentException</code> is thrown.
75       * 
76       * @param values the sequence this model represents
77       * @throws IllegalArugmentException if <code>values</code> is
78       *    <code>null</code> or zero length
79       */
80      public SpinnerListModel(Object  [] values) {
81          if (values == null || values.length == 0) {
82              throw new IllegalArgumentException  ("SpinnerListModel(Object[]) expects non-null non-empty Object[]");
83          }
84      this.list = Arrays.asList(values);
85          this.index = 0;
86      }
87  
88  
89      /**
90       * Constructs an effectively empty <code>SpinnerListModel</code>.  
91       * The model's list will contain a single
92       * <code>"empty"</code> string element.
93       */
94      public SpinnerListModel() {
95      this(new Object  []{"empty"});
96      }
97  
98  
99      /**
100      * Returns the <code>List</code> that defines the sequence for this model.
101      * 
102      * @return the value of the <code>list</code> property
103      * @see #setList
104      */
105     public List<?> getList() {
106     return list;
107     }
108 
109 
110     /**
111      * Changes the list that defines this sequence and resets the index
112      * of the models <code>value</code> to zero.  Note that <code>list</code>
113      * is not copied, the model just stores a reference to it.
114      * <p>
115      * This method fires a <code>ChangeEvent</code> if <code>list</code> is
116      * not equal to the current list.
117      * 
118      * @param list the sequence that this model represents
119      * @throws IllegalArgumentException if <code>list</code> is 
120      *    <code>null</code> or zero length
121      * @see #getList
122      */
123     public void setList(List<?> list) {
124     if ((list == null) || (list.size() == 0)) {
125         throw new IllegalArgumentException  ("invalid list");
126     }
127     if (!list.equals(this.list)) {
128         this.list = list;
129         index = 0;
130         fireStateChanged();
131     }
132     }
133 
134 
135     /**
136      * Returns the current element of the sequence.
137      * 
138      * @return the <code>value</code> property
139      * @see SpinnerModel#getValue
140      * @see #setValue
141      */
142     public Object   getValue() {
143     return list.get(index);
144     }
145 
146 
147     /**
148      * Changes the current element of the sequence and notifies
149      * <code>ChangeListeners</code>.  If the specified
150      * value is not equal to an element of the underlying sequence
151      * then an <code>IllegalArgumentException</code> is thrown.  
152      * In the following example the <code>setValue</code> call 
153      * would cause an exception to be thrown:
154      * <pre>
155      * String[] values = {"one", "two", "free", "four"};
156      * SpinnerModel model = new SpinnerListModel(values);
157      * model.setValue("TWO");
158      * </pre>
159      * 
160      * @param elt the sequence element that will be model's current value
161      * @throws IllegalArgumentException if the specified value isn't allowed
162      * @see SpinnerModel#setValue
163      * @see #getValue
164      */
165     public void setValue(Object   elt) {
166     int index = list.indexOf(elt);
167     if (index == -1) {
168         throw new IllegalArgumentException  ("invalid sequence element");
169     }
170     else if (index != this.index) {
171         this.index = index;
172         fireStateChanged();
173     }
174     }
175 
176 
177     /**
178      * Returns the next legal value of the underlying sequence or
179      * <code>null</code> if value is already the last element.
180      * 
181      * @return the next legal value of the underlying sequence or
182      *     <code>null</code> if value is already the last element
183      * @see SpinnerModel#getNextValue
184      * @see #getPreviousValue
185      */
186     public Object   getNextValue() {
187     return (index >= (list.size() - 1)) ? null : list.get(index + 1);
188     }
189 
190 
191     /**
192      * Returns the previous element of the underlying sequence or
193      * <code>null</code> if value is already the first element.
194      * 
195      * @return the previous element of the underlying sequence or 
196      *     <code>null</code> if value is already the first element 
197      * @see SpinnerModel#getPreviousValue
198      * @see #getNextValue
199      */
200     public Object   getPreviousValue() {
201     return (index <= 0) ? null : list.get(index - 1);
202     }
203 
204 
205     /**
206      * Returns the next object that starts with <code>substring</code>.
207      *
208      * @param substring the string to be matched
209      * @return the match
210      */
211     Object   findNextMatch(String   substring) {
212         int max = list.size();
213 
214         if (max == 0) {
215             return null;
216         }
217         int counter = index;
218 
219         do {
220             Object   value = list.get(counter);
221             String   string = value.toString();
222 
223             if (string != null && string.startsWith(substring)) {
224                 return value;
225             }
226             counter = (counter + 1) % max;
227         } while (counter != index);
228         return null;
229     }
230 }
231 
232
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