    /**
     * @author Ed Spencer
     * @class Ext.data.writer.Writer
     * @extends Object
     *
     * <p>Base Writer class used by most subclasses of {@link Ext.data.proxy.Server}. This class is
     * responsible for taking a set of {@link Ext.data.Operation} objects and a {@link Ext.data.Request}
     * object and modifying that request based on the Operations.</p>
     *
     * <p>For example a Ext.data.writer.Json would format the Operations and their {@link Ext.data.Model}
     * instances based on the config options passed to the JsonWriter's constructor.</p>
     *
     * <p>Writers are not needed for any kind of local storage - whether via a
     * {@link Ext.data.proxy.WebStorage Web Storage proxy} (see {@link Ext.data.proxy.LocalStorage localStorage}
     * and {@link Ext.data.proxy.SessionStorage sessionStorage}) or just in memory via a
     * {@link Ext.data.proxy.Memory MemoryProxy}.</p>
     *
     * @constructor
     * @param {Object} config Optional config object
     */
    Ext.define('Ext.data.writer.Writer', {
        alias: 'writer.base',
        alternateClassName: ['Ext.data.DataWriter', 'Ext.data.Writer'],

        /**
         * @cfg {Boolean} writeAllFields True to write all fields from the record to the server. If set to false it
         * will only send the fields that were modified. Defaults to <tt>true</tt>. Note that any fields that have
         * {@link Ext.data.Field#persist} set to false will still be ignored.
         */
        writeAllFields: true,

        /**
         * @cfg {String} nameProperty This property is used to read the key for each value that will be sent to the server.
         * For example:
         * <pre><code>
    Ext.define('Person', {
        extend: 'Ext.data.Model',
        fields: [{
            name: 'first',
            mapping: 'firstName'
        }, {
            name: 'last',
            mapping: 'lastName'
        }, {
            name: 'age'
        }]
    });
    new Ext.data.writer.Writer({
        writeAllFields: true,
        nameProperty: 'mapping'
    });

    // This will be sent to the server
    {
        firstName: 'first name value',
        lastName: 'last name value',
        age: 1
    }

         * </code></pre>
         * Defaults to <tt>name</tt>. If the value is not present, the field name will always be used.
         */
        nameProperty: 'name',

        constructor: function(config) {
            Ext.apply(this, config);
        },

        /**
         * Prepares a Proxy's Ext.data.Request object
         * @param {Ext.data.Request} request The request object
         * @return {Ext.data.Request} The modified request object
         */
        write: function(request) {
            var operation = request.operation,
                records   = operation.records || [],
                len       = records.length,
                i         = 0,
                data      = [];

            for (; i < len; i++) {
                data.push(this.getRecordData(records[i]));
            }
            return this.writeRecords(request, data);
        },

        /**
         * Formats the data for each record before sending it to the server. This
         * method should be overridden to format the data in a way that differs from the default.
         * @param {Object} record The record that we are writing to the server.
         * @return {Object} An object literal of name/value keys to be written to the server.
         * By default this method returns the data property on the record.
         */
        getRecordData: function(record) {
            var isPhantom = record.phantom === true,
                writeAll = this.writeAllFields || isPhantom,
                nameProperty = this.nameProperty,
                fields = record.fields,
                data = {},
                changes,
                name,
                field,
                key;

            if (writeAll) {
                fields.each(function(field){
                    if (field.persist) {
                        name = field[nameProperty] || field.name;
                        data[name] = record.get(field.name);
                    }
                });
            } else {
                // Only write the changes
                changes = record.getChanges();
                for (key in changes) {
                    if (changes.hasOwnProperty(key)) {
                        field = fields.get(key);
                        name = field[nameProperty] || field.name;
                        data[name] = changes[key];
                    }
                }
                if (!isPhantom) {
                    // always include the id for non phantoms
                    data[record.idProperty] = record.getId();
                }
            }
            return data;
        }
    });