1 /*
2 * Copyright (c) 2000, 2014, 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 import java.io.Serializable;
31
32
33 /**
34 * This class provides the ChangeListener part of the
35 * SpinnerModel interface that should be suitable for most concrete SpinnerModel
36 * implementations. Subclasses must provide an implementation of the
37 * <code>setValue</code>, <code>getValue</code>, <code>getNextValue</code> and
38 * <code>getPreviousValue</code> methods.
39 *
40 * @see JSpinner
41 * @see SpinnerModel
42 * @see SpinnerListModel
43 * @see SpinnerNumberModel
44 * @see SpinnerDateModel
45 *
46 * @author Hans Muller
47 * @since 1.4
48 */
49 @SuppressWarnings("serial") // Field contents are not serializable across versions
50 public abstract class AbstractSpinnerModel implements SpinnerModel, Serializable
51 {
52
53 /**
54 * Only one ChangeEvent is needed per model instance since the
55 * event's only (read-only) state is the source property. The source
56 * of events generated here is always "this".
57 */
58 private transient ChangeEvent changeEvent = null;
59
60
61 /**
62 * The list of ChangeListeners for this model. Subclasses may
63 * store their own listeners here.
64 */
65 protected EventListenerList listenerList = new EventListenerList();
66
67
68 /**
69 * Adds a ChangeListener to the model's listener list. The
70 * ChangeListeners must be notified when the models value changes.
71 *
72 * @param l the ChangeListener to add
73 * @see #removeChangeListener
74 * @see SpinnerModel#addChangeListener
75 */
76 public void addChangeListener(ChangeListener l) {
77 listenerList.add(ChangeListener.class, l);
78 }
79
80
81 /**
82 * Removes a ChangeListener from the model's listener list.
83 *
84 * @param l the ChangeListener to remove
85 * @see #addChangeListener
86 * @see SpinnerModel#removeChangeListener
87 */
88 public void removeChangeListener(ChangeListener l) {
89 listenerList.remove(ChangeListener.class, l);
90 }
91
92
93 /**
94 * Returns an array of all the <code>ChangeListener</code>s added
95 * to this AbstractSpinnerModel with addChangeListener().
96 *
97 * @return all of the <code>ChangeListener</code>s added or an empty
98 * array if no listeners have been added
99 * @since 1.4
100 */
101 public ChangeListener[] getChangeListeners() {
102 return listenerList.getListeners(ChangeListener.class);
103 }
104
105
106 /**
107 * Run each ChangeListeners stateChanged() method.
108 *
109 * @see #setValue
110 * @see EventListenerList
111 */
112 protected void fireStateChanged()
113 {
114 Object[] listeners = listenerList.getListenerList();
115 for (int i = listeners.length - 2; i >= 0; i -=2 ) {
116 if (listeners[i] == ChangeListener.class) {
117 if (changeEvent == null) {
118 changeEvent = new ChangeEvent(this);
119 }
120 ((ChangeListener)listeners[i+1]).stateChanged(changeEvent);
121 }
122 }
123 }
124
125
126 /**
127 * Return an array of all the listeners of the given type that
128 * were added to this model. For example to find all of the
129 * ChangeListeners added to this model:
130 * <pre>
131 * myAbstractSpinnerModel.getListeners(ChangeListener.class);
132 * </pre>
133 *
134 * @param listenerType the type of listeners to return, e.g. ChangeListener.class
135 * @return all of the objects receiving <em>listenerType</em> notifications
136 * from this model
137 */
138 public <T extends EventListener> T[] getListeners(Class<T> listenerType) {
139 return listenerList.getListeners(listenerType);
140 }
141 }