/*

 * Copyright 1995-2004 Sun Microsystems, Inc.  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.  Sun designates this

 * particular file as subject to the "Classpath" exception as provided

 * by Sun 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 Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,

 * CA 95054 USA or visit www.sun.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 + "]";

    }

}