1 /*
2 * Copyright (c) 2000, 2007, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation. Oracle designates this
8 * particular file as subject to the "Classpath" exception as provided
9 * by Oracle in the LICENSE file that accompanied this code.
10 *
11 * This code is distributed in the hope that it will be useful, but WITHOUT
12 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
13 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
14 * version 2 for more details (a copy is included in the LICENSE file that
15 * accompanied this code).
16 *
17 * You should have received a copy of the GNU General Public License version
18 * 2 along with this work; if not, write to the Free Software Foundation,
19 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
20 *
21 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
22 * or visit www.oracle.com if you need additional information or have any
23 * questions.
24 */
25
26 package javax.swing;
27
28 import java.util.*;
29 import javax.swing.event.*;
30
31
32 /**
33 * This class provides the ChangeListener part of the
34 * SpinnerModel interface that should be suitable for most concrete SpinnerModel
35 * implementations. Subclasses must provide an implementation of the
36 * <code>setValue</code>, <code>getValue</code>, <code>getNextValue</code> and
37 * <code>getPreviousValue</code> methods.
38 *
39 * @see JSpinner
40 * @see SpinnerModel
41 * @see SpinnerListModel
42 * @see SpinnerNumberModel
43 * @see SpinnerDateModel
44 *
45 * @author Hans Muller
46 * @since 1.4
47 */
48 public abstract class AbstractSpinnerModel implements SpinnerModel
49 {
50
51 /**
52 * Only one ChangeEvent is needed per model instance since the
53 * event's only (read-only) state is the source property. The source
54 * of events generated here is always "this".
55 */
56 private transient ChangeEvent changeEvent = null;
57
58
59 /**
60 * The list of ChangeListeners for this model. Subclasses may
61 * store their own listeners here.
62 */
63 protected EventListenerList listenerList = new EventListenerList();
64
65
66 /**
67 * Adds a ChangeListener to the model's listener list. The
68 * ChangeListeners must be notified when the models value changes.
69 *
70 * @param l the ChangeListener to add
71 * @see #removeChangeListener
72 * @see SpinnerModel#addChangeListener
73 */
74 public void addChangeListener(ChangeListener l) {
75 listenerList.add(ChangeListener.class, l);
76 }
77
78
79 /**
80 * Removes a ChangeListener from the model's listener list.
81 *
82 * @param l the ChangeListener to remove
83 * @see #addChangeListener
84 * @see SpinnerModel#removeChangeListener
85 */
86 public void removeChangeListener(ChangeListener l) {
87 listenerList.remove(ChangeListener.class, l);
88 }
89
90
91 /**
92 * Returns an array of all the <code>ChangeListener</code>s added
93 * to this AbstractSpinnerModel with addChangeListener().
94 *
95 * @return all of the <code>ChangeListener</code>s added or an empty
96 * array if no listeners have been added
97 * @since 1.4
98 */
99 public ChangeListener[] getChangeListeners() {
100 return listenerList.getListeners(ChangeListener.class);
101 }
102
103
104 /**
105 * Run each ChangeListeners stateChanged() method.
106 *
107 * @see #setValue
108 * @see EventListenerList
109 */
110 protected void fireStateChanged()
111 {
112 Object[] listeners = listenerList.getListenerList();
113 for (int i = listeners.length - 2; i >= 0; i -=2 ) {
114 if (listeners[i] == ChangeListener.class) {
115 if (changeEvent == null) {
116 changeEvent = new ChangeEvent(this);
117 }
118 ((ChangeListener)listeners[i+1]).stateChanged(changeEvent);
119 }
120 }
121 }
122
123
124 /**
125 * Return an array of all the listeners of the given type that
126 * were added to this model. For example to find all of the
127 * ChangeListeners added to this model:
128 * <pre>
129 * myAbstractSpinnerModel.getListeners(ChangeListener.class);
130 * </pre>
131 *
132 * @param listenerType the type of listeners to return, e.g. ChangeListener.class
133 * @return all of the objects receiving <em>listenerType</em> notifications
134 * from this model
135 */
136 public <T extends EventListener> T[] getListeners(Class<T> listenerType) {
137 return listenerList.getListeners(listenerType);
138 }
139 }