Java example source code file (CheckboxGroup.java)

This example Java source code file (CheckboxGroup.java) is included in the alvinalexander.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" ^TM.

Learn more about this Java project at its project page.

Java - Java tags/keywords

checkbox, checkboxgroup, deprecated, string

The CheckboxGroup.java Java example source code

/*
 * Copyright (c) 1995, 2013, 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 class is used to group together
 * a set of <code>Checkbox buttons.
 * <p>
 * Exactly one check box button in a <code>CheckboxGroup 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:
 *
 * <hr>
 * 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>

 * <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."
 * style="float:center; margin: 7px 10px;">
 * <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.
     */
    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 if all check boxes in the
     * group are off.
     * @return   the check box that is currently in the
     *                 "on" state, or <code>null.
     * @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().
     */
    @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, 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 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).
     */
    @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 + "]";
    }

}