datasource-local.js revision fe0ea97b22b09645b8fd2c2d03492479e030a88c
/**
* The DataSource utility provides a common configurable interface for widgets to
* access a variety of data, from JavaScript arrays to online database servers.
*
* @module datasource
*/
var LANG = Y.Lang,
/**
* Base class for the YUI DataSource utility.
* @class DataSource.Local
* @extends Base
* @constructor
*/
DSLocal = function() {
DSLocal.superclass.constructor.apply(this, arguments);
};
/////////////////////////////////////////////////////////////////////////////
//
// DataSource static properties
//
/////////////////////////////////////////////////////////////////////////////
Y.mix(DSLocal, {
/**
* Class name.
*
* @property NAME
* @type String
* @static
* @final
* @value "dataSourceLocal"
*/
NAME: "dataSourceLocal",
/////////////////////////////////////////////////////////////////////////////
//
// DataSource Attributes
//
/////////////////////////////////////////////////////////////////////////////
ATTRS: {
/**
* @attribute source
* @description Pointer to live data.
* @type MIXED
* @default null
*/
source: {
value: null
}
},
/**
* Global transaction counter.
*
* @property DataSource._tId
* @type Number
* @static
* @private
* @default 0
*/
_tId: 0,
/**
* Executes a given callback. The third param determines whether to execute
*
* @method DataSource.issueCallback
* @param callback {Object} The callback object.
* @param params {Array} params to be passed to the callback method
* @param error {Boolean} whether an error occurred
* @static
*/
issueCallback: function (e) {
if(e.callback) {
var callbackFunc = (e.error && e.callback.failure) || e.callback.success;
if (callbackFunc) {
callbackFunc(e);
}
}
}
});
Y.extend(DSLocal, Y.Base, {
/**
* Internal init() handler.
*
* @method initializer
* @param config {Object} Config object.
* @private
*/
initializer: function(config) {
this._initEvents();
},
/**
* This method creates all the events for this module.
* @method _initEvents
* @private
*/
_initEvents: function() {
/**
* Fired when a data request is received.
*
* @event request
* @param e {Event.Facade} Event Facade with the following properties:
* <dl>
* <dt>tId (Number)</dt> <dd>Unique transaction ID.</dd>
* <dt>request (Object)</dt> <dd>The request.</dd>
* <dt>callback (Object)</dt> <dd>The callback object.</dd>
* <dt>cfg (Object)</dt> <dd>Configuration object.</dd>
* </dl>
* @preventable _defRequestFn
*/
this.publish("request", {defaultFn: Y.bind("_defRequestFn", this), queuable:true});
/**
* Fired when raw data is received.
*
* @event data
* @param e {Event.Facade} Event Facade with the following properties:
* <dl>
* <dt>tId (Number)</dt> <dd>Unique transaction ID.</dd>
* <dt>request (Object)</dt> <dd>The request.</dd>
* <dt>callback (Object)</dt> <dd>The callback object with the following properties:
* <dl>
* <dt>success (Function)</dt> <dd>Success handler.</dd>
* <dt>failure (Function)</dt> <dd>Failure handler.</dd>
* </dl>
* </dd>
* <dt>cfg (Object)</dt> <dd>Configuration object.</dd>
* <dt>data (Object)</dt> <dd>Raw data.</dd>
* </dl>
* @preventable _defDataFn
*/
this.publish("data", {defaultFn: Y.bind("_defDataFn", this), queuable:true});
/**
* Fired when response is returned.
*
* @event response
* @param e {Event.Facade} Event Facade with the following properties:
* <dl>
* <dt>tId (Number)</dt> <dd>Unique transaction ID.</dd>
* <dt>request (Object)</dt> <dd>The request.</dd>
* <dt>callback (Object)</dt> <dd>The callback object with the following properties:
* <dl>
* <dt>success (Function)</dt> <dd>Success handler.</dd>
* <dt>failure (Function)</dt> <dd>Failure handler.</dd>
* </dl>
* </dd>
* <dt>cfg (Object)</dt> <dd>Configuration object.</dd>
* <dt>data (Object)</dt> <dd>Raw data.</dd>
* <dt>response (Object)</dt> <dd>Normalized response object with the following properties:
* <dl>
* <dt>results (Object)</dt> <dd>Parsed results.</dd>
* <dt>meta (Object)</dt> <dd>Parsed meta data.</dd>
* <dt>error (Boolean)</dt> <dd>Error flag.</dd>
* </dl>
* </dd>
* </dl>
* @preventable _defResponseFn
*/
this.publish("response", {defaultFn: Y.bind("_defResponseFn", this), queuable:true});
/**
* Fired when an error is encountered.
*
* @event error
* @param e {Event.Facade} Event Facade with the following properties:
* <dl>
* <dt>tId (Number)</dt> <dd>Unique transaction ID.</dd>
* <dt>request (Object)</dt> <dd>The request.</dd>
* <dt>callback (Object)</dt> <dd>The callback object with the following properties:
* <dl>
* <dt>success (Function)</dt> <dd>Success handler.</dd>
* <dt>failure (Function)</dt> <dd>Failure handler.</dd>
* </dl>
* </dd>
* <dt>cfg (Object)</dt> <dd>Configuration object.</dd>
* <dt>data (Object)</dt> <dd>Raw data.</dd>
* <dt>response (Object)</dt> <dd>Normalized response object with the following properties:
* <dl>
* <dt>results (Object)</dt> <dd>Parsed results.</dd>
* <dt>meta (Object)</dt> <dd>Parsed meta data.</dd>
* <dt>error (Object)</dt> <dd>Error object.</dd>
* </dl>
* </dd>
* </dl>
*/
},
/**
* Manages request/response transaction. Must fire <code>response</code>
* event when response is received. This method should be implemented by
* subclasses to achieve more complex behavior such as accessing remote data.
*
* @method _defRequestFn
* @param e {Event.Facade} Event Facadewith the following properties:
* <dl>
* <dt>tId (Number)</dt> <dd>Unique transaction ID.</dd>
* <dt>request (Object)</dt> <dd>The request.</dd>
* <dt>callback (Object)</dt> <dd>The callback object with the following properties:
* <dl>
* <dt>success (Function)</dt> <dd>Success handler.</dd>
* <dt>failure (Function)</dt> <dd>Failure handler.</dd>
* </dl>
* </dd>
* <dt>cfg (Object)</dt> <dd>Configuration object.</dd>
* </dl>
* @protected
*/
_defRequestFn: function(e) {
var data = this.get("source");
// Problematic data
if(LANG.isUndefined(data)) {
e.error = new Error("Local source undefined");
}
if(e.error) {
this.fire("error", e);
Y.log("Error in response", "error", "datasource-local");
}
this.fire("data", Y.mix({data:data}, e));
Y.log("Transaction " + e.tId + " complete. Request: " +
Y.dump(e.request) + " . Response: " + Y.dump(e.response), "info", "datasource-local");
},
/**
* Normalizes raw data into a response that includes results and meta properties.
*
* @method _defDataFn
* @param e {Event.Facade} Event Facade with the following properties:
* <dl>
* <dt>tId (Number)</dt> <dd>Unique transaction ID.</dd>
* <dt>request (Object)</dt> <dd>The request.</dd>
* <dt>callback (Object)</dt> <dd>The callback object with the following properties:
* <dl>
* <dt>success (Function)</dt> <dd>Success handler.</dd>
* <dt>failure (Function)</dt> <dd>Failure handler.</dd>
* </dl>
* </dd>
* <dt>cfg (Object)</dt> <dd>Configuration object.</dd>
* <dt>data (Object)</dt> <dd>Raw data.</dd>
* </dl>
* @protected
*/
_defDataFn: function(e) {
var data = e.data,
meta = e.meta,
response = {
results: (LANG.isArray(data)) ? data : [data],
meta: (meta) ? meta : {}
};
this.fire("response", Y.mix({response: response}, e));
},
/**
* Sends data as a normalized response to callback.
*
* @method _defResponseFn
* @param e {Event.Facade} Event Facade with the following properties:
* <dl>
* <dt>tId (Number)</dt> <dd>Unique transaction ID.</dd>
* <dt>request (Object)</dt> <dd>The request.</dd>
* <dt>callback (Object)</dt> <dd>The callback object with the following properties:
* <dl>
* <dt>success (Function)</dt> <dd>Success handler.</dd>
* <dt>failure (Function)</dt> <dd>Failure handler.</dd>
* </dl>
* </dd>
* <dt>cfg (Object)</dt> <dd>Configuration object.</dd>
* <dt>data (Object)</dt> <dd>Raw data.</dd>
* <dt>response (Object)</dt> <dd>Normalized response object with the following properties:
* <dl>
* <dt>results (Object)</dt> <dd>Parsed results.</dd>
* <dt>meta (Object)</dt> <dd>Parsed meta data.</dd>
* <dt>error (Boolean)</dt> <dd>Error flag.</dd>
* </dl>
* </dd>
* </dl>
* @protected
*/
_defResponseFn: function(e) {
// Send the response back to the callback
DSLocal.issueCallback(e);
},
/**
* Generates a unique transaction ID and fires <code>request</code> event.
*
* @method sendRequest
* @param request {Object} Request.
* @param callback {Object} An object literal with the following properties:
* <dl>
* <dt><code>success</code></dt>
* <dd>The function to call when the data is ready.</dd>
* <dt><code>failure</code></dt>
* <dd>The function to call upon a response failure condition.</dd>
* <dt><code>argument</code></dt>
* <dd>Arbitrary data payload that will be passed back to the success and failure handlers.</dd>
* </dl>
* @param cfg {Object} Configuration object
* @return {Number} Transaction ID.
*/
sendRequest: function(request, callback, cfg) {
var tId = DSLocal._tId++;
this.fire("request", {tId:tId, request:request, callback:callback, cfg:cfg || {}});
Y.log("Transaction " + tId + " sent request: " + Y.dump(request), "info", "datasource-local");
return tId;
}
});
Y.namespace("DataSource").Local = DSLocal;