    /**
     * @class Ext.grid.feature.Summary
     * @extends Ext.grid.feature.AbstractSummary
     *
     * This feature is used to place a summary row at the bottom of the grid. If using a grouping,
     * see {@link Ext.grid.feature.GroupingSummary}. There are 2 aspects to calculating the summaries,
     * calculation and rendering.
     *
     * ## Calculation
     * The summary value needs to be calculated for each column in the grid. This is controlled
     * by the summaryType option specified on the column. There are several built in summary types,
     * which can be specified as a string on the column configuration. These call underlying methods
     * on the store:
     *
     *  - {@link Ext.data.Store#count count}
     *  - {@link Ext.data.Store#sum sum}
     *  - {@link Ext.data.Store#min min}
     *  - {@link Ext.data.Store#max max}
     *  - {@link Ext.data.Store#average average}
     *
     * Alternatively, the summaryType can be a function definition. If this is the case,
     * the function is called with an array of records to calculate the summary value.
     *
     * ## Rendering
     * Similar to a column, the summary also supports a summaryRenderer function. This
     * summaryRenderer is called before displaying a value. The function is optional, if
     * not specified the default calculated value is shown. The summaryRenderer is called with:
     *
     *  - value {Object} - The calculated value.
     *  - summaryData {Object} - Contains all raw summary values for the row.
     *  - field {String} - The name of the field we are calculating
     *
     * ## Example Usage
     *
     *     Ext.define('TestResult', {
     *         extend: 'Ext.data.Model',
     *         fields: ['student', {
     *             name: 'mark',
     *             type: 'int'
     *         }]
     *     });
     *
     *     Ext.create('Ext.grid.Panel', {
     *         width: 200,
     *         height: 140,
     *         renderTo: document.body,
     *         features: [{
     *             ftype: 'summary'
     *         }],
     *         store: {
     *             model: 'TestResult',
     *             data: [{
     *                 student: 'Student 1',
     *                 mark: 84
     *             },{
     *                 student: 'Student 2',
     *                 mark: 72
     *             },{
     *                 student: 'Student 3',
     *                 mark: 96
     *             },{
     *                 student: 'Student 4',
     *                 mark: 68
     *             }]
     *         },
     *         columns: [{
     *             dataIndex: 'student',
     *             text: 'Name',
     *             summaryType: 'count',
     *             summaryRenderer: function(value, summaryData, dataIndex) {
     *                 return Ext.String.format('{0} student{1}', value, value !== 1 ? 's' : '');
     *             }
     *         }, {
     *             dataIndex: 'mark',
     *             text: 'Mark',
     *             summaryType: 'average'
     *         }]
     *     });
     */
    Ext.define('Ext.grid.feature.Summary', {

        /* Begin Definitions */

        extend: 'Ext.grid.feature.AbstractSummary',

        alias: 'feature.summary',

        /* End Definitions */

        /**
         * Gets any fragments needed for the template.
         * @private
         * @return {Object} The fragments
         */
        getFragmentTpl: function() {
            // this gets called before render, so we'll setup the data here.
            this.summaryData = this.generateSummaryData();
            return this.getSummaryFragments();
        },

        /**
         * Overrides the closeRows method on the template so we can include our own custom
         * footer.
         * @private
         * @return {Object} The custom fragments
         */
        getTableFragments: function(){
            if (this.showSummaryRow) {
                return {
                    closeRows: this.closeRows
                };
            }
        },

        /**
         * Provide our own custom footer for the grid.
         * @private
         * @return {String} The custom footer
         */
        closeRows: function() {
            return '</tpl>{[this.printSummaryRow()]}';
        },

        /**
         * Gets the data for printing a template row
         * @private
         * @param {Number} index The index in the template
         * @return {Array} The template values
         */
        getPrintData: function(index){
            var me = this,
                columns = me.view.headerCt.getColumnsForTpl(),
                i = 0,
                length = columns.length,
                data = [],
                active = me.summaryData,
                column;

            for (; i < length; ++i) {
                column = columns[i];
                column.gridSummaryValue = this.getColumnValue(column, active);
                data.push(column);
            }
            return data;
        },

        /**
         * Generates all of the summary data to be used when processing the template
         * @private
         * @return {Object} The summary data
         */
        generateSummaryData: function(){
            var me = this,
                data = {},
                store = me.view.store,
                columns = me.view.headerCt.getColumnsForTpl(),
                i = 0,
                length = columns.length,
                fieldData,
                key,
                comp;

            for (i = 0, length = columns.length; i < length; ++i) {
                comp = Ext.getCmp(columns[i].id);
                data[comp.id] = me.getSummary(store, comp.summaryType, comp.dataIndex, false);
            }
            return data;
        }
    });