datasource-debug.js

这是YUI的源码及相关示例。里面有很多很炫的Javascript效果。

/*
Copyright (c) 2008, Yahoo! Inc. All rights reserved.
Code licensed under the BSD License:
http://developer.yahoo.net/yui/license.txt
version: 2.6.0
*/
(function () {

var lang   = YAHOO.lang,
    util   = YAHOO.util,
    Ev     = util.Event;

/**
 * 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
 * @requires yahoo, event
 * @optional json, get, connection 
 * @title DataSource Utility
 */

/****************************************************************************/
/****************************************************************************/
/****************************************************************************/

/**
 * Base class for the YUI DataSource utility.
 *
 * @namespace YAHOO.util
 * @class YAHOO.util.DataSourceBase
 * @constructor
 * @param oLiveData {HTMLElement}  Pointer to live data.
 * @param oConfigs {object} (optional) Object literal of configuration values.
 */
util.DataSourceBase = function(oLiveData, oConfigs) {
    if(oLiveData === null || oLiveData === undefined) {
        YAHOO.log("Could not instantiate DataSource due to invalid live database",
                "error", this.toString());
        return;
    }
    
    this.liveData = oLiveData;
    this._oQueue = {interval:null, conn:null, requests:[]};
    this.responseSchema = {};   

    // Set any config params passed in to override defaults
    if(oConfigs && (oConfigs.constructor == Object)) {
        for(var sConfig in oConfigs) {
            if(sConfig) {
                this[sConfig] = oConfigs[sConfig];
            }
        }
    }
    
    // Validate and initialize public configs
    var maxCacheEntries = this.maxCacheEntries;
    if(!lang.isNumber(maxCacheEntries) || (maxCacheEntries < 0)) {
        maxCacheEntries = 0;
    }

    // Initialize interval tracker
    this._aIntervals = [];

    /////////////////////////////////////////////////////////////////////////////
    //
    // Custom Events
    //
    /////////////////////////////////////////////////////////////////////////////

    /**
     * Fired when a request is made to the local cache.
     *
     * @event cacheRequestEvent
     * @param oArgs.request {Object} The request object.
     * @param oArgs.callback {Object} The callback object.
     * @param oArgs.caller {Object} (deprecated) Use callback.scope.
     */
    this.createEvent("cacheRequestEvent");

    /**
     * Fired when data is retrieved from the local cache.
     *
     * @event cacheResponseEvent
     * @param oArgs.request {Object} The request object.
     * @param oArgs.response {Object} The response object.
     * @param oArgs.callback {Object} The callback object.
     * @param oArgs.caller {Object} (deprecated) Use callback.scope.
     */
    this.createEvent("cacheResponseEvent");

    /**
     * Fired when a request is sent to the live data source.
     *
     * @event requestEvent
     * @param oArgs.request {Object} The request object.
     * @param oArgs.callback {Object} The callback object.
     * @param oArgs.tId {Number} Transaction ID.     
     * @param oArgs.caller {Object} (deprecated) Use callback.scope.
     */
    this.createEvent("requestEvent");

    /**
     * Fired when live data source sends response.
     *
     * @event responseEvent
     * @param oArgs.request {Object} The request object.
     * @param oArgs.response {Object} The raw response object.
     * @param oArgs.callback {Object} The callback object.
     * @param oArgs.tId {Number} Transaction ID.     
     * @param oArgs.caller {Object} (deprecated) Use callback.scope.
     */
    this.createEvent("responseEvent");

    /**
     * Fired when response is parsed.
     *
     * @event responseParseEvent
     * @param oArgs.request {Object} The request object.
     * @param oArgs.response {Object} The parsed response object.
     * @param oArgs.callback {Object} The callback object.
     * @param oArgs.caller {Object} (deprecated) Use callback.scope.
     */
    this.createEvent("responseParseEvent");

    /**
     * Fired when response is cached.
     *
     * @event responseCacheEvent
     * @param oArgs.request {Object} The request object.
     * @param oArgs.response {Object} The parsed response object.
     * @param oArgs.callback {Object} The callback object.
     * @param oArgs.caller {Object} (deprecated) Use callback.scope.
     */
    this.createEvent("responseCacheEvent");
    /**
     * Fired when an error is encountered with the live data source.
     *
     * @event dataErrorEvent
     * @param oArgs.request {Object} The request object.
     * @param oArgs.callback {Object} The callback object.
     * @param oArgs.caller {Object} (deprecated) Use callback.scope.
     * @param oArgs.message {String} The error message.
     */
    this.createEvent("dataErrorEvent");

    /**
     * Fired when the local cache is flushed.
     *
     * @event cacheFlushEvent
     */
    this.createEvent("cacheFlushEvent");

    var DS = util.DataSourceBase;
    this._sName = "DataSource instance" + DS._nIndex;
    DS._nIndex++;
    YAHOO.log("DataSource initialized", "info", this.toString());
};

var DS = util.DataSourceBase;

lang.augmentObject(DS, {

/////////////////////////////////////////////////////////////////////////////
//
// DataSourceBase public constants
//
/////////////////////////////////////////////////////////////////////////////

/**
 * Type is unknown.
 *
 * @property TYPE_UNKNOWN
 * @type Number
 * @final
 * @default -1
 */
TYPE_UNKNOWN : -1,

/**
 * Type is a JavaScript Array.
 *
 * @property TYPE_JSARRAY
 * @type Number
 * @final
 * @default 0
 */
TYPE_JSARRAY : 0,

/**
 * Type is a JavaScript Function.
 *
 * @property TYPE_JSFUNCTION
 * @type Number
 * @final
 * @default 1
 */
TYPE_JSFUNCTION : 1,

/**
 * Type is hosted on a server via an XHR connection.
 *
 * @property TYPE_XHR
 * @type Number
 * @final
 * @default 2
 */
TYPE_XHR : 2,

/**
 * Type is JSON.
 *
 * @property TYPE_JSON
 * @type Number
 * @final
 * @default 3
 */
TYPE_JSON : 3,

/**
 * Type is XML.
 *
 * @property TYPE_XML
 * @type Number
 * @final
 * @default 4
 */
TYPE_XML : 4,

/**
 * Type is plain text.
 *
 * @property TYPE_TEXT
 * @type Number
 * @final
 * @default 5
 */
TYPE_TEXT : 5,

/**
 * Type is an HTML TABLE element. Data is parsed out of TR elements from all TBODY elements.
 *
 * @property TYPE_HTMLTABLE
 * @type Number
 * @final
 * @default 6
 */
TYPE_HTMLTABLE : 6,

/**
 * Type is hosted on a server via a dynamic script node.
 *
 * @property TYPE_SCRIPTNODE
 * @type Number
 * @final
 * @default 7
 */
TYPE_SCRIPTNODE : 7,

/**
 * Type is local.
 *
 * @property TYPE_LOCAL
 * @type Number
 * @final
 * @default 8
 */
TYPE_LOCAL : 8,

/**
 * Error message for invalid dataresponses.
 *
 * @property ERROR_DATAINVALID
 * @type String
 * @final
 * @default "Invalid data"
 */
ERROR_DATAINVALID : "Invalid data",

/**
 * Error message for null data responses.
 *
 * @property ERROR_DATANULL
 * @type String
 * @final
 * @default "Null data"
 */
ERROR_DATANULL : "Null data",

/////////////////////////////////////////////////////////////////////////////
//
// DataSourceBase private static properties
//
/////////////////////////////////////////////////////////////////////////////

/**
 * Internal class variable to index multiple DataSource instances.
 *
 * @property DataSourceBase._nIndex
 * @type Number
 * @private
 * @static
 */
_nIndex : 0,

/**
 * Internal class variable to assign unique transaction IDs.
 *
 * @property DataSourceBase._nTransactionId
 * @type Number
 * @private
 * @static
 */
_nTransactionId : 0,

/////////////////////////////////////////////////////////////////////////////
//
// DataSourceBase public static methods
//
/////////////////////////////////////////////////////////////////////////////

/**
 * Executes a configured callback.  For object literal callbacks, the third
 * param determines whether to execute the success handler or failure handler.
 *  
 * @method issueCallback
 * @param callback {Function|Object} the callback to execute
 * @param params {Array} params to be passed to the callback method
 * @param error {Boolean} whether an error occurred
 * @param scope {Object} the scope from which to execute the callback
 * (deprecated - use an object literal callback)
 * @static     
 */
issueCallback : function (callback,params,error,scope) {
    if (lang.isFunction(callback)) {
        callback.apply(scope, params);
    } else if (lang.isObject(callback)) {
        scope = callback.scope || scope || window;
        var callbackFunc = callback.success;
        if (error) {
            callbackFunc = callback.failure;
        }
        if (callbackFunc) {
            callbackFunc.apply(scope, params.concat([callback.argument]));
        }
    }
},

/**
 * Converts data to type String.
 *
 * @method DataSourceBase.parseString
 * @param oData {String | Number | Boolean | Date | Array | Object} Data to parse.
 * The special values null and undefined will return null.
 * @return {Number} A string, or null.
 * @static
 */
parseString : function(oData) {
    // Special case null and undefined
    if(!lang.isValue(oData)) {
        return null;
    }
    
    //Convert to string
    var string = oData + "";

    // Validate
    if(lang.isString(string)) {
        return string;
    }
    else {
        YAHOO.log("Could not convert data " + lang.dump(oData) + " to type String", "warn", this.toString());
        return null;
    }
},

/**
 * Converts data to type Number.
 *
 * @method DataSourceBase.parseNumber
 * @param oData {String | Number | Boolean | Null} Data to convert. Beware, null
 * returns as 0.
 * @return {Number} A number, or null if NaN.
 * @static
 */
parseNumber : function(oData) {
    //Convert to number
    var number = oData * 1;