/* * Copyright (c) 1995, 2004, Oracle and/or its affiliates. All rights reserved. * 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 * by Oracle in the LICENSE file that accompanied this code. * * 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. * * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA * or visit www.oracle.com if you need additional information or have any * questions. */package java.awt; /** * The <code>CheckboxGroup</code> class is used to group together * a set of <code>Checkbox</code> buttons. * <p> * Exactly one check box button in a <code>CheckboxGroup</code> can * be in the "on" state at any given time. Pushing any * button sets its state to "on" and forces any other button that * is in the "on" state into the "off" state. * <p> * The following code example produces a new check box group, * with three check boxes: * <p> * <hr><blockquote><pre> * setLayout(new GridLayout(3, 1)); * CheckboxGroup cbg = new CheckboxGroup(); * add(new Checkbox("one", cbg, true)); * add(new Checkbox("two", cbg, false)); * add(new Checkbox("three", cbg, false)); * </pre></blockquote><hr> * <p> * This image depicts the check box group created by this example: * <p> * <img src="doc-files/CheckboxGroup-1.gif" * alt="Shows three checkboxes, arranged vertically, labeled one, two, and three. Checkbox one is in the on state." * ALIGN=center HSPACE=10 VSPACE=7> * <p> * @author      Sami Shaio * @see         java.awt.Checkbox * @since       JDK1.0 */public class CheckboxGroup implements java.io.Serializable {    /**     * The current choice.     * @serial     * @see #getCurrent()     * @see #setCurrent(Checkbox)     */    Checkbox selectedCheckbox = null;     /*     * JDK 1.1 serialVersionUID     */    private static final long serialVersionUID = 3729780091441768983L;     /**     * Creates a new instance of <code>CheckboxGroup</code>.     */    public CheckboxGroup() {    }     /**     * Gets the current choice from this check box group.     * The current choice is the check box in this     * group that is currently in the "on" state,     * or <code>null</code> if all check boxes in the     * group are off.     * @return   the check box that is currently in the     *                 "on" state, or <code>null</code>.     * @see      java.awt.Checkbox     * @see      java.awt.CheckboxGroup#setSelectedCheckbox     * @since    JDK1.1     */    public Checkbox getSelectedCheckbox() {        return getCurrent();    }     /**     * @deprecated As of JDK version 1.1,     * replaced by <code>getSelectedCheckbox()</code>.     */    @Deprecated    public Checkbox getCurrent() {        return selectedCheckbox;    }     /**     * Sets the currently selected check box in this group     * to be the specified check box.     * This method sets the state of that check box to "on" and     * sets all other check boxes in the group to be off.     * <p>     * If the check box argument is <tt>null</tt>, all check boxes     * in this check box group are deselected. If the check box argument     * belongs to a different check box group, this method does     * nothing.     * @param     box   the <code>Checkbox</code> to set as the     *                      current selection.     * @see      java.awt.Checkbox     * @see      java.awt.CheckboxGroup#getSelectedCheckbox     * @since    JDK1.1     */    public void setSelectedCheckbox(Checkbox box) {        setCurrent(box);    }     /**     * @deprecated As of JDK version 1.1,     * replaced by <code>setSelectedCheckbox(Checkbox)</code>.     */    @Deprecated    public synchronized void setCurrent(Checkbox box) {        if (box != null && box.group != this) {            return;        }        Checkbox oldChoice = this.selectedCheckbox;        this.selectedCheckbox = box;        if (oldChoice != null && oldChoice != box && oldChoice.group == this) {            oldChoice.setState(false);        }        if (box != null && oldChoice != box && !box.getState()) {            box.setStateInternal(true);        }    }     /**     * Returns a string representation of this check box group,     * including the value of its current selection.     * @return    a string representation of this check box group.     */    public String toString() {        return getClass().getName() + "[selectedCheckbox=" + selectedCheckbox + "]";    } }