/**
                             Paginator's core functionality consists of keeping track of the current page
                             being displayed and providing information for previous and next pages.
                            
                             @module paginator
                             @submodule paginator-core
                             @since 3.11.0
                             */
                            
                            /**
                             _API docs for this extension are included in the Paginator class._
                            
                             Class extension providing the core API and structure for the Paginator module.
                            
                             Use this class extension with Widget or another Base-based superclass to
                             create the basic Paginator model API and composing class structure.
                            
                             @class Paginator.Core
                             @for Paginator
                             @since 3.11.0
                             */
                            
                            var PaginatorCore = Y.namespace('Paginator').Core = function () {};
                            
                            PaginatorCore.ATTRS = {
                                /**
                                 Current page count. First page is 1.
                            
                                 @attribute page
                                 @type Number
                                 @default 1
                                 **/
                                page: {
                                    value: 1
                                },
                            
                                /**
                                 Total number of pages to display
                            
                                 @readOnly
                                 @attribute totalPages
                                 @type Number
                                 **/
                                totalPages: {
                                    readOnly: true,
                                    getter: '_getTotalPagesFn'
                                },
                            
                                /**
                                 Maximum number of items per page. A value of negative one (-1) indicates
                                     all items on one page.
                            
                                 @attribute itemsPerPage
                                 @type Number
                                 @default 10
                                 **/
                                itemsPerPage: {
                                    value: 10
                                },
                            
                                /**
                                 Total number of items in all pages.
                            
                                 @attribute totalItems
                                 @type Number
                                 @default 0
                                 **/
                                totalItems: {
                                    value: 0
                                }
                            };
                            
                            Y.mix(PaginatorCore.prototype, {
                                /**
                                 Sets the page to the previous page in the set, if there is a previous page.
                                 @method prevPage
                                 @chainable
                                 */
                                prevPage: function () {
                                    if (this.hasPrevPage()) {
                                        this.set('page', this.get('page') - 1);
                                    }
                            
                                    return this;
                                },
                            
                                /**
                                 Sets the page to the next page in the set, if there is a next page.
                            
                                 @method nextPage
                                 @chainable
                                 */
                                nextPage: function () {
                                    if (this.hasNextPage()) {
                                        this.set('page', this.get('page') + 1);
                                    }
                            
                                    return this;
                                },
                            
                                /**
                                 Returns True if there is a previous page in the set.
                            
                                 @method hasPrevPage
                                 @return {Boolean} `true` if there is a previous page, `false` otherwise.
                                 */
                                hasPrevPage: function () {
                                    return this.get('page') > 1;
                                },
                            
                                /**
                                 Returns True if there is a next page in the set.
                            
                                 If totalItems isn't set, assume there is always next page.
                            
                                 @method hasNextPage
                                 @return {Boolean} `true` if there is a next page, `false` otherwise.
                                 */
                                hasNextPage: function () {
                                    return (!this.get('totalItems') || this.get('page') < this.get('totalPages'));
                                },
                            
                            
                                //--- P R O T E C T E D
                            
                                /**
                                 Returns the total number of pages based on the total number of
                                   items provided and the number of items per page
                            
                                 @protected
                                 @method _getTotalPagesFn
                                 @return {Number} Total number of pages based on total number of items and
                                   items per page or one if itemsPerPage is less than one
                                 */
                                _getTotalPagesFn: function () {
                                    var itemsPerPage = this.get('itemsPerPage');
                            
                                    return (itemsPerPage < 1) ? 1 : Math.ceil(this.get('totalItems') / itemsPerPage);
                                }
                            });