/**
                             * The Rating Utility - The Thumb Rating creates a non-obstrusive star rating
                             * control with only two options using Thumb Up and Thumb Down icons.
                             *
                             * @module aui-rating
                             */
                            
                            var getCN = A.getClassName,
                            
                                CSS_ICON = getCN('glyphicon'),
                                CSS_ICON_THUMBS_DOWN = getCN('glyphicon', 'thumbs', 'down'),
                                CSS_ICON_THUMBS_UP = getCN('glyphicon', 'thumbs', 'up'),
                                CSS_RATING_OFF = getCN('rating', 'off'),
                                CSS_RATING_ON = getCN('rating', 'on');
                            
                            /**
                             * A base class for ThumbRating, providing:
                             *
                             * - A non-obstrusive star rating control using Thumb up and Thumb down icons
                             * - Could be based on a set of radio input boxes
                             *
                             * Check the [live demo](http://alloyui.com/examples/rating/).
                             *
                             * @class A.ThumbRating
                             * @extends A.Rating
                             * @param {Object} config Object literal specifying widget configuration
                             *     properties.
                             * @constructor
                             */
                            var ThumbRating = A.Component.create({
                                /**
                                 * Static property provides a string to identify the class.
                                 *
                                 * @property NAME
                                 * @type String
                                 * @static
                                 */
                                NAME: 'ThumbRating',
                            
                                /**
                                 * Static property used to define the default attribute
                                 * configuration for the ThumbRating.
                                 *
                                 * @property ATTRS
                                 * @type Object
                                 * @static
                                 */
                                ATTRS: {
                            
                                    /**
                                     * CSS classes applied on ThumbRating.
                                     *
                                     * @attribute cssClasses
                                     * @type Object
                                     */
                                    cssClasses: {
                                        value: {
                                            down: [CSS_ICON, CSS_ICON_THUMBS_DOWN].join(' '),
                                            element: CSS_RATING_OFF,
                                            hover: CSS_RATING_ON,
                                            off: CSS_RATING_OFF,
                                            on: CSS_RATING_ON,
                                            up: [CSS_ICON, CSS_ICON_THUMBS_UP].join(' ')
                                        }
                                    },
                            
                                    /**
                                     * The size on ThumbRating is always 2 (i.e., thumb up and thumb down).
                                     *
                                     * @attribute size
                                     * @default 2
                                     * @readOnly
                                     * @type Number
                                     */
                                    size: {
                                        value: 2,
                                        readOnly: true
                                    }
                                },
                            
                                /**
                                 * Static property used to define which component it extends.
                                 *
                                 * @property EXTENDS
                                 * @type Object
                                 * @static
                                 */
                                EXTENDS: A.Rating,
                            
                                prototype: {
                            
                                    /**
                                     * Create the DOM structure for the ThumbRating. Lifecycle.
                                     *
                                     * @method renderUI
                                     * @protected
                                     */
                                    renderUI: function() {
                                        var instance = this,
                                            cssClasses = instance.get('cssClasses');
                            
                                        ThumbRating.superclass.renderUI.apply(this, arguments);
                            
                                        var elements = instance.get('elements');
                            
                                        elements.addClass(cssClasses.off);
                                        elements.item(0).addClass(cssClasses.up);
                                        elements.item(1).addClass(cssClasses.down);
                                    },
                            
                                    /**
                                     * Add the `className` on the the `index` element
                                     * and all the previous Rating elements.
                                     *
                                     * @method fillTo
                                     * @param {Number} index Index to be selected
                                     * @param {String} className Class name to be applied when fill the
                                     *     Rating elements
                                     */
                                    fillTo: function(index) {
                                        var instance = this,
                                            cssClasses = instance.get('cssClasses');
                            
                                        this.clearSelection();
                            
                                        if (index >= 0) {
                                            var el = this.get('elements').item(index);
                                            el.addClass(cssClasses.on);
                                            el.removeClass(cssClasses.off);
                                        }
                                    },
                            
                                    /**
                                     * Empty method, no logic needed on this method on ThumbRating.
                                     *
                                     * @method _syncElements
                                     * @protected
                                     */
                                    _syncElements: function() {}
                                }
                            });
                            
                            A.ThumbRating = ThumbRating;