1 /* SpinnerListModel.java -- A spinner model backed by a list or an array.
2 Copyright (C) 2004, 2005 Free Software Foundation, Inc.
4 This file is part of GNU Classpath.
6 GNU Classpath is free software; you can redistribute it and/or modify
7 it under the terms of the GNU General Public License as published by
8 the Free Software Foundation; either version 2, or (at your option)
11 GNU Classpath is distributed in the hope that it will be useful, but
12 WITHOUT ANY WARRANTY; without even the implied warranty of
13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
14 General Public License for more details.
16 You should have received a copy of the GNU General Public License
17 along with GNU Classpath; see the file COPYING. If not, write to the
18 Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
21 Linking this library statically or dynamically with other modules is
22 making a combined work based on this library. Thus, the terms and
23 conditions of the GNU General Public License cover the whole
26 As a special exception, the copyright holders of this library give you
27 permission to link this library with independent modules to produce an
28 executable, regardless of the license terms of these independent
29 modules, and to copy and distribute the resulting executable under
30 terms of your choice, provided that you also meet, for each linked
31 independent module, the terms and conditions of the license of that
32 module. An independent module is a module which is not derived from
33 or based on this library. If you modify this library, you may extend
34 this exception to your version of the library, but you are not
35 obligated to do so. If you do not wish to do so, delete this
36 exception statement from your version. */
40 import java.io.Serializable;
41 import java.util.ArrayList;
42 import java.util.Arrays;
43 import java.util.List;
45 import javax.swing.event.ChangeEvent;
48 * An implementation of <code>SpinnerModel</code> which uses the values
49 * contained within a list or an array. The backing list or array is
50 * only stored as a reference within the class. As a result, changes
51 * made elsewhere to the members of the list or array are reflected by
55 * The model itself inherits a list of <code>ChangeListener</code>s from
56 * <code>AbstractSpinnerModel</code>. As this code is unaware of changes
57 * made to the backing list or array, it is the responsibility of the
58 * application using the model to invoke <code>fireStateChanged()</code>,
59 * in order to notify any <code>ChangeListener</code>s, when the list or array
60 * changes. The model handles notification when the reference itself
61 * is changed via <code>setList()</code> or when the current value is
62 * set directly using <code>setValue()</code>.
64 * @author Andrew John Hughes (gnu_andrew@member.fsf.org)
66 * @see AbstractSpinnerModel
71 public class SpinnerListModel
72 extends AbstractSpinnerModel
73 implements Serializable
76 * For compatability with Sun's JDK
78 private static final long serialVersionUID = 3358804052191994516L;
81 * The backing list for this model.
86 * The current index in the list.
88 private transient int index;
91 * Constructs a default <code>SpinnerListModel</code>. This
92 * is a model backed by a list containing only the single
93 * <code>String</code> element, "empty".
95 public SpinnerListModel()
99 /* Create an empty list */
100 defaultList = new ArrayList();
101 /* Add the string "empty" */
102 defaultList.add("empty");
104 setList(defaultList);
108 * Constructs a <code>SpinnerListModel</code> using the supplied list.
109 * The model maintains a reference to this list, and returns
110 * consecutive elements in response to calls to <code>getNextValue()</code>.
111 * The initial value is that at position 0, so an initial call
112 * to <code>getValue()</code> returns the same as <code>list.get(0)</code>.
114 * @param list The list to use for this model.
115 * @throws IllegalArgumentException if the list is null or contains no
117 * @see SpinnerListModel#getNextValue()
118 * @see SpinnerListModel#getValue()
120 public SpinnerListModel(List list)
122 /* Retain a reference to the valid list */
127 * Constructs a <code>SpinnerListModel</code> using the supplied array.
128 * The model stores a reference to the wrapper list returned by
129 * <code>Arrays.asList()</code>. The wrapper list reflects modifications
130 * in the underlying array, so these changes will also be reflected
131 * by the model. The model produces consecutive elements from the array
132 * in response to calls to <code>getNextValue()</code>. The initial
133 * value returned by <code>getValue()</code> is the same as
134 * <code>array[0]</code>.
136 * @param array The array to use for this model.
137 * @throws IllegalArgumentException if the array is null or contains
139 * @see Arrays#asList(Object[])
140 * @see SpinnerListModel#getNextValue()
141 * @see SpinnerListModel#getValue()
143 public SpinnerListModel(Object[] array)
145 /* Check for a null or zero-sized array */
146 if (array == null || array.length == 0)
148 throw new IllegalArgumentException("The supplied array was invalid.");
151 Retain a reference to a wrapper around the valid array
152 The array, in list form, will be tested again here, but we can't really
153 avoid this -- a null value to Arrays.asList will throw a NullPointerException
155 setList(Arrays.asList(array));
159 * Returns the backing list for this model.
161 * @return The backing list.
163 public List getList()
169 * Returns the next value from the list, which is the same as the element
170 * stored at the current index + 1. Null is returned if there are no more
171 * values to be returned (the end of the list has been reached). An
172 * ambiguity can occur here, as null may also be returned as a valid list
173 * element. This operation does not change the current value.
175 * @return The next value from the list or null.
177 public Object getNextValue()
179 /* Check for a next value */
180 if (index < (list.size() - 1))
182 /* Return the element at the next index */
183 return list.get(index + 1);
187 /* Return null as this is the end of the list */
193 * Returns the previous value from the list, which is the same as the element
194 * stored at the current index - 1. Null is returned if there are no more
195 * values to be returned (the start of the list has been reached). An
196 * ambiguity can occur here, as null may also be returned as a valid list
197 * element. This operation does not change the current value.
199 * @return The previous value from the list or null.
201 public Object getPreviousValue()
203 /* Check for a previous value. */
206 /* Return the element at the previous position */
207 return list.get(index - 1);
211 /* Return null as this is the start of the list */
217 * Returns the current value of the model. Initially, this will
218 * be the element at position 0. On later invocations, this will
219 * be the last element returned by <code>getNextValue()</code>
220 * or <code>getPreviousValue()</code>.
222 * @return The current value.
223 * @see SpinnerListModel#getPreviousValue()
224 * @see SpinnerListModel#getNextValue()
226 public Object getValue()
228 return list.get(index);
232 * Changes the backing list for this model. The model only stores
233 * a reference to the list, so any changes made to the list elsewhere
234 * will be reflected in the values returned by the model. A
235 * <code>ChangeEvent</code> is fired if the list being used actually
236 * changes (i.e. the new list is not referentially equal (!=) to the
239 * @param list The new list to use.
240 * @throws IllegalArgumentException if the list is null or contains
244 public void setList(List list)
246 /* Check for null or zero size list */
247 if (list == null || list.size() == 0)
249 throw new IllegalArgumentException("The supplied list was invalid.");
251 /* Check for a change of referenced list */
252 if (this.list != list)
254 /* Store the new list */
256 /* Notify listeners of a change */
259 /* We reset the other values in either case */
260 /* Set the index to 0 */
265 * Sets the current value of the model to be the one supplied.
266 * The value must exist within the backing list in order for
267 * the change to take place. Otherwise, an exception is thrown.
268 * The value used is the first occurrence of the value within
269 * the backing list. Listeners are notified of this change.
270 * Following the change, <code>getNextValue()</code> and
271 * <code>getPreviousValue()</code> return the objects following
272 * and prior to the supplied value, respectively.
274 * @param value The requested new value of the list.
275 * @throws IllegalArgumentException if the supplied value does
276 * not exist in the backing list.
277 * @see SpinnerListModel#getPreviousValue()
278 * @see SpinnerListModel#getNextValue()
280 public void setValue(Object value)
284 /* Search for the value in the list */
285 valueIndex = list.indexOf(value);
286 /* Check for the value being found */
287 if (valueIndex == -1)
289 throw new IllegalArgumentException("The supplied value does not "
290 + "exist in this list");
292 /* Make the indices match */
294 /* Notify the listeners */