1 /* 2 * Copyright (c) 2000, 2008, 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 public abstract class AbstractSpinnerModel implements SpinnerModel, Serializable 50 { 51 52 /** 53 * Only one ChangeEvent is needed per model instance since the 54 * event's only (read-only) state is the source property. The source 55 * of events generated here is always "this". 56 */ 57 private transient ChangeEvent changeEvent = null; 58 59 60 /** 61 * The list of ChangeListeners for this model. Subclasses may 62 * store their own listeners here. 63 */ 64 protected EventListenerList listenerList = new EventListenerList(); 65 66 67 /** 68 * Adds a ChangeListener to the model's listener list. The 69 * ChangeListeners must be notified when the models value changes. 70 * 71 * @param l the ChangeListener to add 72 * @see #removeChangeListener 73 * @see SpinnerModel#addChangeListener 74 */ 75 public void addChangeListener(ChangeListener l) { 76 listenerList.add(ChangeListener.class, l); 77 } 78 79 80 /** 81 * Removes a ChangeListener from the model's listener list. 82 * 83 * @param l the ChangeListener to remove 84 * @see #addChangeListener 85 * @see SpinnerModel#removeChangeListener 86 */ 87 public void removeChangeListener(ChangeListener l) { 88 listenerList.remove(ChangeListener.class, l); 89 } 90 91 92 /** 93 * Returns an array of all the <code>ChangeListener</code>s added 94 * to this AbstractSpinnerModel with addChangeListener(). 95 * 96 * @return all of the <code>ChangeListener</code>s added or an empty 97 * array if no listeners have been added 98 * @since 1.4 99 */ 100 public ChangeListener[] getChangeListeners() { 101 return listenerList.getListeners(ChangeListener.class); 102 } 103 104 105 /** 106 * Run each ChangeListeners stateChanged() method. 107 * 108 * @see #setValue 109 * @see EventListenerList 110 */ 111 protected void fireStateChanged() 112 { 113 Object[] listeners = listenerList.getListenerList(); 114 for (int i = listeners.length - 2; i >= 0; i -=2 ) { 115 if (listeners[i] == ChangeListener.class) { 116 if (changeEvent == null) { 117 changeEvent = new ChangeEvent(this); 118 } 119 ((ChangeListener)listeners[i+1]).stateChanged(changeEvent); 120 } 121 } 122 } 123 124 125 /** 126 * Return an array of all the listeners of the given type that 127 * were added to this model. For example to find all of the 128 * ChangeListeners added to this model: 129 * <pre> 130 * myAbstractSpinnerModel.getListeners(ChangeListener.class); 131 * </pre> 132 * 133 * @param listenerType the type of listeners to return, e.g. ChangeListener.class 134 * @return all of the objects receiving <em>listenerType</em> notifications 135 * from this model 136 */ 137 public <T extends EventListener> T[] getListeners(Class<T> listenerType) { 138 return listenerList.getListeners(listenerType); 139 } 140 }