    /**
     * A {@link Ext.form.FieldContainer field container} which has a specialized layout for arranging
     * {@link Ext.form.field.Radio} controls into columns, and provides convenience {@link Ext.form.field.Field}
     * methods for {@link #getValue getting}, {@link #setValue setting}, and {@link #validate validating} the
     * group of radio buttons as a whole.
     *
     * # Validation
     *
     * Individual radio buttons themselves have no default validation behavior, but
     * sometimes you want to require a user to select one of a group of radios. RadioGroup
     * allows this by setting the config `{@link #allowBlank}:false`; when the user does not check at
     * one of the radio buttons, the entire group will be highlighted as invalid and the
     * {@link #blankText error message} will be displayed according to the {@link #msgTarget} config.</p>
     *
     * # Layout
     *
     * The default layout for RadioGroup makes it easy to arrange the radio buttons into
     * columns; see the {@link #columns} and {@link #vertical} config documentation for details. You may also
     * use a completely different layout by setting the {@link #layout} to one of the other supported layout
     * types; for instance you may wish to use a custom arrangement of hbox and vbox containers. In that case
     * the Radio components at any depth will still be managed by the RadioGroup's validation.
     *
     * {@img Ext.form.RadioGroup/Ext.form.RadioGroup.png Ext.form.RadioGroup component}
     *
     * # Example usage
     *
     *     Ext.create('Ext.form.Panel', {
     *         title: 'RadioGroup Example',
     *         width: 300,
     *         height: 125,
     *         bodyPadding: 10,
     *         renderTo: Ext.getBody(),
     *         items:[{
     *             xtype: 'radiogroup',
     *             fieldLabel: 'Two Columns',
     *             // Arrange radio buttons into two columns, distributed vertically
     *             columns: 2,
     *             vertical: true,
     *             items: [
     *                 {boxLabel: 'Item 1', name: 'rb', inputValue: '1'},
     *                 {boxLabel: 'Item 2', name: 'rb', inputValue: '2', checked: true},
     *                 {boxLabel: 'Item 3', name: 'rb', inputValue: '3'},
     *                 {boxLabel: 'Item 4', name: 'rb', inputValue: '4'},
     *                 {boxLabel: 'Item 5', name: 'rb', inputValue: '5'},
     *                 {boxLabel: 'Item 6', name: 'rb', inputValue: '6'}
     *             ]
     *         }]
     *     });
     *
     */
    Ext.define('Ext.form.RadioGroup', {
        extend: 'Ext.form.CheckboxGroup',
        alias: 'widget.radiogroup',

        /**
         * @cfg {Array} items An Array of {@link Ext.form.field.Radio Radio}s or Radio config objects
         * to arrange in the group.
         */
        /**
         * @cfg {Boolean} allowBlank True to allow every item in the group to be blank (defaults to true).
         * If allowBlank = false and no items are selected at validation time, {@link #blankText} will
         * be used as the error text.
         */
        allowBlank : true,
        /**
         * @cfg {String} blankText Error text to display if the {@link #allowBlank} validation fails
         * (defaults to 'You must select one item in this group')
         */
        blankText : 'You must select one item in this group',

        // private
        defaultType : 'radiofield',

        // private
        groupCls : Ext.baseCSSPrefix + 'form-radio-group',

        getBoxes: function() {
            return this.query('[isRadio]');
        }

    });