DefaultSingleSelectionModel.java

/*
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 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
 *
 * This code is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License version 2 only, as
 * published by the Free Software Foundation. Oracle designates this
 * particular file as subject to the "Classpath" exception as provided
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 *
 * This code is distributed in the hope that it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
 * version 2 for more details (a copy is included in the LICENSE file that
 * accompanied this code).
 *
 * You should have received a copy of the GNU General Public License version
 * 2 along with this work; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
 *
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packagejavax.swing;

importjavax.swing.event.*;
importjava.io.Serializable;
importjava.util.EventListener;

/**
 * A generic implementation of SingleSelectionModel.
 * <p>
 * <strong>Warning:</strong>
 * Serialized objects of this class will not be compatible with
 * future Swing releases. The current serialization support is
 * appropriate for short term storage or RMI between applications running
 * the same version of Swing. As of 1.4, support for long term storage
 * of all JavaBeans
 * has been added to the <code>java.beans</code> package.
 * Please see {@link java.beans.XMLEncoder}.
 *
 * @author Dave Moore
 * @since 1.2
 */
@SuppressWarnings("serial") // Same-version serialization only
publicclassDefaultSingleSelectionModelimplementsSingleSelectionModel,
Serializable {
/**
 * Only one ModelChangeEvent is needed per model instance since the
 * event's only (read-only) state is the source property. The source
 * of events generated here is always "this".
 */
protectedtransientChangeEventchangeEvent = null;
/** The collection of registered listeners */
protectedEventListenerListlistenerList = newEventListenerList();

privateintindex = -1;

/**
 * Constructs a {@code DefaultSingleSelectionModel}.
 */
publicDefaultSingleSelectionModel() {}

/**
 * {@inheritDoc}
 */
publicintgetSelectedIndex() {
returnindex;
 }

/**
 * {@inheritDoc}
 */
publicvoidsetSelectedIndex(intindex) {
if (this.index != index) {
this.index = index;
fireStateChanged();
 }
 }

/**
 * {@inheritDoc}
 */
publicvoidclearSelection() {
setSelectedIndex(-1);
 }

/**
 * {@inheritDoc}
 */
publicbooleanisSelected() {
booleanret = false;
if (getSelectedIndex() != -1) {
ret = true;
 }
returnret;
 }

/**
 * Adds a <code>ChangeListener</code> to the button.
 */
publicvoidaddChangeListener(ChangeListenerl) {
listenerList.add(ChangeListener.class, l);
 }

/**
 * Removes a <code>ChangeListener</code> from the button.
 */
publicvoidremoveChangeListener(ChangeListenerl) {
listenerList.remove(ChangeListener.class, l);
 }

/**
 * Returns an array of all the change listeners
 * registered on this <code>DefaultSingleSelectionModel</code>.
 *
 * @return all of this model's <code>ChangeListener</code>s
 * or an empty
 * array if no change listeners are currently registered
 *
 * @see #addChangeListener
 * @see #removeChangeListener
 *
 * @since 1.4
 */
publicChangeListener[] getChangeListeners() {
returnlistenerList.getListeners(ChangeListener.class);
 }

/**
 * Notifies all listeners that have registered interest for
 * notification on this event type. The event instance
 * is created lazily.
 * @see EventListenerList
 */
protectedvoidfireStateChanged() {
// Guaranteed to return a non-null array
Object[] listeners = listenerList.getListenerList();
// Process the listeners last to first, notifying
// those that are interested in this event
for (inti = listeners.length-2; i>=0; i-=2) {
if (listeners[i]==ChangeListener.class) {
// Lazily create the event:
if (changeEvent == null)
changeEvent = newChangeEvent(this);
 ((ChangeListener)listeners[i+1]).stateChanged(changeEvent);
 }
 }
 }

/**
 * Returns an array of all the objects currently registered as
 * <code><em>Foo</em>Listener</code>s
 * upon this model.
 * <code><em>Foo</em>Listener</code>s
 * are registered using the <code>add<em>Foo</em>Listener</code> method.
 * <p>
 * You can specify the <code>listenerType</code> argument
 * with a class literal, such as <code><em>Foo</em>Listener.class</code>.
 * For example, you can query a <code>DefaultSingleSelectionModel</code>
 * instance <code>m</code>
 * for its change listeners
 * with the following code:
 *
 * <pre>ChangeListener[] cls = (ChangeListener[])(m.getListeners(ChangeListener.class));</pre>
 *
 * If no such listeners exist,
 * this method returns an empty array.
 *
 * @param <T> the type of {@code EventListener} class being requested
 * @param listenerType the type of listeners requested;
 * this parameter should specify an interface
 * that descends from <code>java.util.EventListener</code>
 * @return an array of all objects registered as
 * <code><em>Foo</em>Listener</code>s
 * on this model,
 * or an empty array if no such
 * listeners have been added
 * @throws ClassCastException if <code>listenerType</code> doesn't
 * specify a class or interface that implements
 * <code>java.util.EventListener</code>
 *
 * @see #getChangeListeners
 *
 * @since 1.3
 */
public <TextendsEventListener> T[] getListeners(Class<T> listenerType) {
returnlistenerList.getListeners(listenerType);
 }
}