/**
 * @author Ed Spencer
 * @class Ext.data.ArrayReader
 * @extends Ext.data.JsonReader
 * 
 * 
Data reader class to create an Array of {@link Ext.data.Model} objects from an Array.
 * Each element of that Array represents a row of data fields. The
 * fields are pulled into a Record object using as a subscript, the mapping property
 * of the field definition if it exists, or the field's ordinal position in the definition.
 * 
 * 
Example code:
 * 

var Employee = Ext.regModel('Employee', {
    fields: [
        'id',
        {name: 'name', mapping: 1},         // "mapping" only needed if an "id" field is present which
        {name: 'occupation', mapping: 2}    // precludes using the ordinal position as the index.        
    ]
});

var myReader = new Ext.data.ArrayReader({
    model: 'Employee'
}, Employee);

 * 
 * 
This would consume an Array like this:
 * 

[ [1, 'Bill', 'Gardener'], [2, 'Ben', 'Horticulturalist'] ]

 * 
 * @constructor
 * Create a new ArrayReader
 * @param {Object} meta Metadata configuration options.
 */
Ext.define('Ext.data.ArrayReader', {
    extend: 'Ext.data.JsonReader',
    alias : 'reader.array',

    /**
     * @private
     * Most of the work is done for us by JsonReader, but we need to overwrite the field accessors to just
     * reference the correct position in the array.
     */
    buildExtractors: function() {
        Ext.data.ArrayReader.superclass.buildExtractors.apply(this, arguments);
        
        var fields = this.model.prototype.fields.items,
            length = fields.length,
            extractorFunctions = [],
            i;
        
        for (i = 0; i < length; i++) {
            extractorFunctions.push(function(index) {
                return function(data) {
                    return data[index];
                };
            }(fields[i].mapping || i));
        }
        
        this.extractorFunctions = extractorFunctions;
    }
});