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package java.awt;


The CheckboxGroup class is used to group together a set of Checkbox buttons. 
 Exactly one check box button in a 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. 

The following code example produces a new check box group,
with three check boxes:

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));




This image depicts the check box group created by this example:




Author:     Sami Shaio
See Also:
Since:      1.0
/**
 * 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><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."
 * style="float:center; margin: 7px 10px;">
 *
 * @author      Sami Shaio
 * @see         java.awt.Checkbox
 * @since       1.0
 */
public class CheckboxGroup implements java.io.Serializable {
    
The current choice.

See Also:
@serial
/**
     * 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 CheckboxGroup. 
/**
     * 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 null if all check boxes in the group are off. 
See Also:
Returns: the check box that is currently in the "on" state, or null.
Since:   1.1
/**
     * 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    1.1
     */
    public Checkbox getSelectedCheckbox() {
        return getCurrent();
    }

    
Returns the current choice from this check box group or null if none of checkboxes are selected. 
Returns:the selected checkbox
Deprecated:As of JDK version 1.1, replaced by getSelectedCheckbox().
/**
     * Returns the current choice from this check box group
     * or {@code null} if none of checkboxes are selected.
     *
     * @return the selected checkbox
     * @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.

 If the check box argument is 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. 
Params:
  • box –  the Checkbox to set as the current selection.
See Also:
Since:   1.1
/**
     * 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 {@code 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    1.1
     */
    public void setSelectedCheckbox(Checkbox box) {
        setCurrent(box);
    }

    
Sets the currently selected check box in this group
to be the specified check box and unsets all others.

Params:
  • box – the Checkbox to set as the current selection.
Deprecated:As of JDK version 1.1, replaced by setSelectedCheckbox(Checkbox).
/**
     * Sets the currently selected check box in this group
     * to be the specified check box and unsets all others.
     *
     * @param  box the {@code Checkbox} to set as the
     *         current selection.
     * @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.

Returns:   a string representation of this check box group.
/**
     * 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 + "]";
    }

}