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 }