# Yahoo! UI Library

### DataSource Utility 2.5.1

Yahoo! UI Library > datasource > DataSource.js (source view)

Show Private Show Protected

    /**
     * The DataSource utility provides a common configurable interface for widgets
     * to access a variety of data, from JavaScript arrays to online servers over
     * XHR.
     *
     * @namespace YAHOO.util
     * @module datasource
     * @requires yahoo, event
     * @optional connection
     * @title DataSource Utility
     * @beta
     */

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

    /**
     * The DataSource class defines and manages a live set of data for widgets to
     * interact with. Examples of live databases include in-memory
     * local data such as a JavaScript array, a JavaScript function, or JSON, or
     * remote data such as data retrieved through an XHR connection.
     *
     * @class DataSource
     * @uses YAHOO.util.EventProvider
     * @constructor
     * @param oLiveData {Object} Pointer to live database.
     * @param oConfigs {Object} (optional) Object literal of configuration values.
     */
    YAHOO.util.DataSource = function(oLiveData, oConfigs) {
        if(!oLiveData) {
            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:[]};

        if(oLiveData.nodeType && oLiveData.nodeType == 9) {
            this.dataType = YAHOO.util.DataSource.TYPE_XML;
        }
        else if(YAHOO.lang.isArray(oLiveData)) {
            this.dataType = YAHOO.util.DataSource.TYPE_JSARRAY;
        }
        else if(YAHOO.lang.isString(oLiveData)) {
            this.dataType = YAHOO.util.DataSource.TYPE_XHR;
        }
        else if(YAHOO.lang.isFunction(oLiveData)) {
            this.dataType = YAHOO.util.DataSource.TYPE_JSFUNCTION;
        }
        else if(oLiveData.nodeName && (oLiveData.nodeName.toLowerCase() == "table")) {
            this.dataType = YAHOO.util.DataSource.TYPE_HTMLTABLE;
            this.liveData = oLiveData.cloneNode(true);
        }
        else if(YAHOO.lang.isObject(oLiveData)) {
            this.dataType = YAHOO.util.DataSource.TYPE_JSON;
        }
        else {
            this.dataType = YAHOO.util.DataSource.TYPE_UNKNOWN;
        }

        // 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(!YAHOO.lang.isNumber(maxCacheEntries) || (maxCacheEntries < 0)) {
            maxCacheEntries = 0;
        }

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

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

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

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

    YAHOO.augment(YAHOO.util.DataSource, YAHOO.util.EventProvider);

    /////////////////////////////////////////////////////////////////////////////
    //
    // Public constants
    //
    /////////////////////////////////////////////////////////////////////////////

    /**
     * Type is unknown.
     *
     * @property TYPE_UNKNOWN
     * @type Number
     * @final
     * @default -1
     */
    YAHOO.util.DataSource.TYPE_UNKNOWN = -1;

    /**
     * Type is a JavaScript Array.
     *
     * @property TYPE_JSARRAY
     * @type Number
     * @final
     * @default 0
     */
    YAHOO.util.DataSource.TYPE_JSARRAY = 0;

    /**
     * Type is a JavaScript Function.
     *
     * @property TYPE_JSFUNCTION
     * @type Number
     * @final
     * @default 1
     */
    YAHOO.util.DataSource.TYPE_JSFUNCTION = 1;

    /**
     * Type is hosted on a server via an XHR connection.
     *
     * @property TYPE_XHR
     * @type Number
     * @final
     * @default 2
     */
    YAHOO.util.DataSource.TYPE_XHR = 2;

    /**
     * Type is JSON.
     *
     * @property TYPE_JSON
     * @type Number
     * @final
     * @default 3
     */
    YAHOO.util.DataSource.TYPE_JSON = 3;

    /**
     * Type is XML.
     *
     * @property TYPE_XML
     * @type Number
     * @final
     * @default 4
     */
    YAHOO.util.DataSource.TYPE_XML = 4;

    /**
     * Type is plain text.
     *
     * @property TYPE_TEXT
     * @type Number
     * @final
     * @default 5
     */
    YAHOO.util.DataSource.TYPE_TEXT = 5;

    /**
     * Type is an HTML TABLE element.
     *
     * @property TYPE_HTMLTABLE
     * @type Number
     * @final
     * @default 6
     */
    YAHOO.util.DataSource.TYPE_HTMLTABLE = 6;

    /**
     * Error message for invalid dataresponses.
     *
     * @property ERROR_DATAINVALID
     * @type String
     * @final
     * @default "Invalid data"
     */
    YAHOO.util.DataSource.ERROR_DATAINVALID = "Invalid data";

    /**
     * Error message for null data responses.
     *
     * @property ERROR_DATANULL
     * @type String
     * @final
     * @default "Null data"
     */
    YAHOO.util.DataSource.ERROR_DATANULL = "Null data";

    /////////////////////////////////////////////////////////////////////////////
    //
    // Private variables
    //
    /////////////////////////////////////////////////////////////////////////////

    /**
     * Internal class variable to index multiple DataSource instances.
     *
     * @property DataSource._nIndex
     * @type Number
     * @private
     * @static
     */
    YAHOO.util.DataSource._nIndex = 0;

    /**
     * Internal class variable to assign unique transaction IDs.
     *
     * @property DataSource._nTransactionId
     * @type Number
     * @private
     * @static
     */
    YAHOO.util.DataSource._nTransactionId = 0;

    /**
     * Name of DataSource instance.
     *
     * @property _sName
     * @type String
     * @private
     */
    YAHOO.util.DataSource.prototype._sName = null;

    /**
     * Local cache of data result object literals indexed chronologically.
     *
     * @property _aCache
     * @type Object[]
     * @private
     */
    YAHOO.util.DataSource.prototype._aCache = null;

    /**
     * Local queue of request connections, enabled if queue needs to be managed.
     *
     * @property _oQueue
     * @type Object
     * @private
     */
    YAHOO.util.DataSource.prototype._oQueue = null;

    /**
     * Array of polling interval IDs that have been enabled, needed to clear all intervals.
     *
     * @property _aIntervals
     * @type Array
     * @private
     */
    YAHOO.util.DataSource.prototype._aIntervals = null;

    /////////////////////////////////////////////////////////////////////////////
    //
    // Private methods
    //
    /////////////////////////////////////////////////////////////////////////////

    /////////////////////////////////////////////////////////////////////////////
    //
    // Public member variables
    //
    /////////////////////////////////////////////////////////////////////////////

    /**
     * Max size of the local cache.  Set to 0 to turn off caching.  Caching is
     * useful to reduce the number of server connections.  Recommended only for data
     * sources that return comprehensive results for queries or when stale data is
     * not an issue.
     *
     * @property maxCacheEntries
     * @type Number
     * @default 0
     */
    YAHOO.util.DataSource.prototype.maxCacheEntries = 0;

     /**
     * Pointer to live database.
     *
     * @property liveData
     * @type Object
     */
    YAHOO.util.DataSource.prototype.liveData = null;

    /**
     * Where the live data is held.
     *
     * @property dataType
     * @type Number
     * @default YAHOO.util.DataSource.TYPE_UNKNOWN
     *
     */
    YAHOO.util.DataSource.prototype.dataType = YAHOO.util.DataSource.TYPE_UNKNOWN;

    /**
     * Format of response.
     *
     * @property responseType
     * @type Number
     * @default YAHOO.util.DataSource.TYPE_UNKNOWN
     */
    YAHOO.util.DataSource.prototype.responseType = YAHOO.util.DataSource.TYPE_UNKNOWN;

    /**
     * Response schema object literal takes a combination of the following properties:
     *
     * <dl>
     * <dt>resultsList</dt> <dd>Pointer to array of tabular data</dd>
     * <dt>resultNode</dt> <dd>Pointer to node name of row data (XML data only)</dd>
     * <dt>recordDelim</dt> <dd>Record delimiter (text data only)</dd>
     * <dt>fieldDelim</dt> <dd>Field delimiter (text data only)</dd>
     * <dt>fields</dt> <dd>Array of field names (aka keys), or array of object literals
     * such as: {key:"fieldname",parser:YAHOO.util.DataSource.parseDate}</dd>
     * <dt>metaFields</dt> <dd>Object literal of keys to include in the oParsedResponse.meta collection</dd>
     * <dt>metaNode</dt> <dd>Name of the node under which to search for meta information in XML response data</dd>
     * </dl>
     *
     * @property responseSchema
     * @type Object
     */
    YAHOO.util.DataSource.prototype.responseSchema = null;

     /**
     * Alias to YUI Connection Manager, to allow implementers to customize the utility.
     *
     * @property connMgr
     * @type Object
     * @default YAHOO.util.Connect
     */
    YAHOO.util.DataSource.prototype.connMgr = null;

     /**
     * If data is accessed over XHR via Connection Manager, this setting defines
     * request/response management in the following manner:
     * <dl>
     *     <dt>queueRequests</dt>
     *     <dd>If a request is already in progress, wait until response is returned
     *     before sending the next request.</dd>
     *
     *     <dt>cancelStaleRequests</dt>
     *     <dd>If a request is already in progress, cancel it before sending the next
     *     request.</dd>
     *
     *     <dt>ignoreStaleResponses</dt>
     *     <dd>Send all requests, but handle only the response for the most recently
     *     sent request.</dd>
     *
     *     <dt>allowAll</dt>
     *     <dd>Send all requests and handle all responses.</dd>
     *
     * </dl>
     *
     * @property connXhrMode
     * @type String
     * @default "allowAll"
     */
    YAHOO.util.DataSource.prototype.connXhrMode = "allowAll";

     /**
     * If data is accessed over XHR via Connection Manager, true if data should be
     * sent via POST, otherwise data will be sent via GET.
     *
     * @property connMethodPost
     * @type Boolean
     * @default false
     */
    YAHOO.util.DataSource.prototype.connMethodPost = false;

     /**
     * If data is accessed over XHR via Connection Manager, the connection timeout
     * defines how many  milliseconds the XHR connection will wait for a server
     * response. Any non-zero value will enable the Connection utility's
     * Auto-Abort feature.
     *
     * @property connTimeout
     * @type Number
     * @default 0
     */
    YAHOO.util.DataSource.prototype.connTimeout = 0;

    /////////////////////////////////////////////////////////////////////////////
    //
    // Public static methods
    //
    /////////////////////////////////////////////////////////////////////////////

    /**
     * Converts data to type String.
     *
     * @method DataSource.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
     */
    YAHOO.util.DataSource.parseString = function(oData) {
        // Special case null and undefined
        if(!YAHOO.lang.isValue(oData)) {
            return null;
        }

        //Convert to string
        var string = oData + "";

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

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

        // Validate
        if(YAHOO.lang.isNumber(number)) {
            return number;
        }
        else {
            YAHOO.log("Could not convert data " + YAHOO.lang.dump(oData) + " to type Number", "warn", this.toString());
            return null;
        }
    };
    // Backward compatibility
    YAHOO.util.DataSource.convertNumber = function(oData) {
        YAHOO.log("The method YAHOO.util.DataSource.convertNumber() has been" +
        " deprecated in favor of YAHOO.util.DataSource.parseNumber()", "warn",
        this.toString());
        return YAHOO.util.DataSource.parseNumber(oData);
    };

    /**
     * Converts data to type Date.
     *
     * @method DataSource.parseDate
     * @param oData {Date | String | Number} Data to convert.
     * @return {Date} A Date instance.
     * @static
     */
    YAHOO.util.DataSource.parseDate = function(oData) {
        var date = null;

        //Convert to date
        if(!(oData instanceof Date)) {
            date = new Date(oData);
        }
        else {
            return oData;
        }

        // Validate
        if(date instanceof Date) {
            return date;
        }
        else {
            YAHOO.log("Could not convert data " + YAHOO.lang.dump(oData) + " to type Date", "warn", this.toString());
            return null;
        }
    };
    // Backward compatibility
    YAHOO.util.DataSource.convertDate = function(oData) {
        YAHOO.log("The method YAHOO.util.DataSource.convertDate() has been" +
        " deprecated in favor of YAHOO.util.DataSource.parseDate()", "warn",
        this.toString());
        return YAHOO.util.DataSource.parseDate(oData);
    };

    /////////////////////////////////////////////////////////////////////////////
    //
    // Public methods
    //
    /////////////////////////////////////////////////////////////////////////////

    /**
     * Public accessor to the unique name of the DataSource instance.
     *
     * @method toString
     * @return {String} Unique name of the DataSource instance.
     */
    YAHOO.util.DataSource.prototype.toString = function() {
        return this._sName;
    };

    /**
     * Overridable method passes request to cache and returns cached response if any,
     * refreshing the hit in the cache as the newest item. Returns null if there is
     * no cache hit.
     *
     * @method getCachedResponse
     * @param oRequest {Object} Request object.
     * @param oCallback {Function} Handler function to receive the response.
     * @param oCaller {Object} The Calling object that is making the request.
     * @return {Object} Cached response object or null.
     */
    YAHOO.util.DataSource.prototype.getCachedResponse = function(oRequest, oCallback, oCaller) {
        var aCache = this._aCache;

        // If cache is enabled...
        if(this.maxCacheEntries > 0) {
            // Initialize local cache
            if(!aCache) {
                this._aCache = [];
                YAHOO.log("Cache initialized", "info", this.toString());
            }
            // Look in local cache
            else {
                var nCacheLength = aCache.length;
                if(nCacheLength > 0) {
                    var oResponse = null;
                    this.fireEvent("cacheRequestEvent", {request:oRequest,callback:oCallback,caller:oCaller});

                    // Loop through each cached element
                    for(var i = nCacheLength-1; i >= 0; i--) {
                        var oCacheElem = aCache[i];

                        // Defer cache hit logic to a public overridable method
                        if(this.isCacheHit(oRequest,oCacheElem.request)) {
                            // The cache returned a hit!
                            // Grab the cached response
                            oResponse = oCacheElem.response;
                            this.fireEvent("cacheResponseEvent", {request:oRequest,response:oResponse,callback:oCallback,caller:oCaller});

                            // Refresh the position of the cache hit
                            if(i < nCacheLength-1) {
                                YAHOO.log("Refreshing cache position of the response for \"" +  oRequest + "\"", "info", this.toString());
                                // Remove element from its original location
                                aCache.splice(i,1);
                                YAHOO.log("Cleared from cache the response for \"" +  oRequest + "\"", "info", this.toString());
                                // Add as newest
                                this.addToCache(oRequest, oResponse);
                            }
                            break;
                        }
                    }
                    YAHOO.log("The cached response for \"" + YAHOO.lang.dump(oRequest) +
                            "\" is " + YAHOO.lang.dump(oResponse), "info", this.toString());
                    return oResponse;
                }
            }
        }
        else if(aCache) {
            this._aCache = null;
            YAHOO.log("Cache destroyed", "info", this.toString());
        }
        return null;
    };

    /**
     * Default overridable method matches given request to given cached request.
     * Returns true if is a hit, returns false otherwise.  Implementers should
     * override this method to customize the cache-matching algorithm.
     *
     * @method isCacheHit
     * @param oRequest {Object} Request object.
     * @param oCachedRequest {Object} Cached request object.
     * @return {Boolean} True if given request matches cached request, false otherwise.
     */
    YAHOO.util.DataSource.prototype.isCacheHit = function(oRequest, oCachedRequest) {
        return (oRequest === oCachedRequest);
    };

    /**
     * Adds a new item to the cache. If cache is full, evicts the stalest item
     * before adding the new item.
     *
     * @method addToCache
     * @param oRequest {Object} Request object.
     * @param oResponse {Object} Response object to cache.
     */
    YAHOO.util.DataSource.prototype.addToCache = function(oRequest, oResponse) {
        var aCache = this._aCache;
        if(!aCache) {
            return;
        }

        // If the cache is full, make room by removing stalest element (index=0)
        while(aCache.length >= this.maxCacheEntries) {
            aCache.shift();
        }

        // Add to cache in the newest position, at the end of the array
        var oCacheElem = {request:oRequest,response:oResponse};
        aCache[aCache.length] = oCacheElem;
        this.fireEvent("responseCacheEvent", {request:oRequest,response:oResponse});
        YAHOO.log("Cached the response for \"" +  oRequest + "\"", "info", this.toString());
    };

    /**
     * Flushes cache.
     *
     * @method flushCache
     */
    YAHOO.util.DataSource.prototype.flushCache = function() {
        if(this._aCache) {
            this._aCache = [];
            this.fireEvent("cacheFlushEvent");
            YAHOO.log("Flushed the cache", "info", this.toString());
        }
    };

    /**
     * Sets up a polling mechanism to send requests at set intervals and forward
     * responses to given callback.
     *
     * @method setInterval
     * @param nMsec {Number} Length of interval in milliseconds.
     * @param oRequest {Object} Request object.
     * @param oCallback {Function} Handler function to receive the response.
     * @param oCaller {Object} (deprecated) Use oCallback.scope.
     * @return {Number} Interval ID.
     */
    YAHOO.util.DataSource.prototype.setInterval = function(nMsec, oRequest, oCallback, oCaller) {
        if(YAHOO.lang.isNumber(nMsec) && (nMsec >= 0)) {
            YAHOO.log("Enabling polling to live data for \"" + oRequest + "\" at interval " + nMsec, "info", this.toString());
            var oSelf = this;
            var nId = setInterval(function() {
                oSelf.makeConnection(oRequest, oCallback, oCaller);
            }, nMsec);
            this._aIntervals.push(nId);
            return nId;
        }
        else {
            YAHOO.log("Could not enable polling to live data for \"" + oRequest + "\" at interval " + nMsec, "info", this.toString());
        }
    };

    /**
     * Disables polling mechanism associated with the given interval ID.
     *
     * @method clearInterval
     * @param nId {Number} Interval ID.
     */
    YAHOO.util.DataSource.prototype.clearInterval = function(nId) {
        // Remove from tracker if there
        var tracker = this._aIntervals || [];
        for(var i=tracker.length-1; i>-1; i--) {
            if(tracker[i] === nId) {
                tracker.splice(i,1);
                clearInterval(nId);
            }
        }
    };

    /**
     * Disables all known polling intervals.
     *
     * @method clearAllIntervals
     */
    YAHOO.util.DataSource.prototype.clearAllIntervals = function(nId) {
        var tracker = this._aIntervals || [];
        for(var i=tracker.length-1; i>-1; i--) {
            tracker.splice(i,1);
            clearInterval(nId);
        }
    };

    /**
     * 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)
     */
    YAHOO.util.DataSource.issueCallback = function (callback,params,error,scope) {
        if (YAHOO.lang.isFunction(callback)) {
            callback.apply(scope, params);
        } else if (YAHOO.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]));
            }
        }
    };

    /**
     * First looks for cached response, then sends request to live data.
     *
     * @method sendRequest
     * @param oRequest {Object} Request object.
     * @param oCallback {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>scope</code></dt>
     *     <dd>The object to serve as the scope for the success and failure handlers.</dd>
     *     <dt><code>argument</code></dt>
     *     <dd>Arbitrary data that will be passed back to the success and failure handlers.</dd>
     *     </dl>
     * @param oCaller {Object} (deprecated) Use oCallback.scope.
     * @return {Number} Transaction ID, or null if response found in cache.
     */
    YAHOO.util.DataSource.prototype.sendRequest = function(oRequest, oCallback, oCaller) {
        // First look in cache
        var oCachedResponse = this.getCachedResponse(oRequest, oCallback, oCaller);
        if(oCachedResponse) {
            YAHOO.util.DataSource.issueCallback(oCallback,[oRequest,oCachedResponse],false,oCaller);
            return null;
        }

        // Not in cache, so forward request to live data
        YAHOO.log("Making connection to live data for \"" + oRequest + "\"", "info", this.toString());
        return this.makeConnection(oRequest, oCallback, oCaller);
    };

    /**
     * Overridable method provides default functionality to make a connection to
     * live data in order to send request. The response coming back is then
     * forwarded to the handleResponse function. This method should be customized
     * to achieve more complex implementations.
     *
     * @method makeConnection
     * @param oRequest {Object} Request object.
     * @param oCallback {Object} Callback object literal.
     * @param oCaller {Object} (deprecated) Use oCallback.scope.
     * @return {Number} Transaction ID.
     */
    YAHOO.util.DataSource.prototype.makeConnection = function(oRequest, oCallback, oCaller) {
        this.fireEvent("requestEvent", {request:oRequest,callback:oCallback,caller:oCaller});
        var oRawResponse = null;
        var tId = YAHOO.util.DataSource._nTransactionId++;

        // How to make the connection depends on the type of data
        switch(this.dataType) {
            // If the live data is a JavaScript Function
            // pass the request in as a parameter and
            // forward the return value to the handler
            case YAHOO.util.DataSource.TYPE_JSFUNCTION:
                oRawResponse = this.liveData(oRequest);
                this.handleResponse(oRequest, oRawResponse, oCallback, oCaller, tId);
                break;
            // If the live data is over Connection Manager
            // set up the callback object and
            // pass the request in as a URL query and
            // forward the response to the handler
            case YAHOO.util.DataSource.TYPE_XHR:
                var oSelf = this;
                var oConnMgr = this.connMgr || YAHOO.util.Connect;
                var oQueue = this._oQueue;

                /**
                 * Define Connection Manager success handler
                 *
                 * @method _xhrSuccess
                 * @param oResponse {Object} HTTPXMLRequest object
                 * @private
                 */
                var _xhrSuccess = function(oResponse) {
                    // If response ID does not match last made request ID,
                    // silently fail and wait for the next response
                    if(oResponse && (this.connXhrMode == "ignoreStaleResponses") &&
                            (oResponse.tId != oQueue.conn.tId)) {
                        YAHOO.log("Ignored stale response", "warn", this.toString());
                        return null;
                    }
                    // Error if no response
                    else if(!oResponse) {
                        this.fireEvent("dataErrorEvent", {request:oRequest,
                                callback:oCallback, caller:oCaller,
                                message:YAHOO.util.DataSource.ERROR_DATANULL});
                        YAHOO.log(YAHOO.util.DataSource.ERROR_DATANULL, "error", this.toString());

                        // Send error response back to the caller with the error flag on
                        // TODO: should this send oResponse, considering the fork?
                        YAHOO.util.DataSource.issueCallback(oCallback,[oRequest, {error:true}], true, oCaller);

                        return null;
                    }
                    // Forward to handler
                    else {
                        this.handleResponse(oRequest, oResponse, oCallback, oCaller, tId);
                    }
                };

                /**
                 * Define Connection Manager failure handler
                 *
                 * @method _xhrFailure
                 * @param oResponse {Object} HTTPXMLRequest object
                 * @private
                 */
                var _xhrFailure = function(oResponse) {
                    this.fireEvent("dataErrorEvent", {request:oRequest,
                            callback:oCallback, caller:oCaller,
                            message:YAHOO.util.DataSource.ERROR_DATAINVALID});
                    YAHOO.log(YAHOO.util.DataSource.ERROR_DATAINVALID + ": " +
                            oResponse.statusText, "error", this.toString());

                    // Backward compatibility
                    if((this.liveData.lastIndexOf("?") !== this.liveData.length-1) &&
                        (oRequest.indexOf("?") !== 0)){
                            YAHOO.log("DataSources using XHR no longer supply a \"?\"" +
                            " between the host and query parameters" +
                            " -- please check that the request URL is correct", "warn", this.toString());
                    }

                    // Send failure response back to the caller with the error flag on
                    oResponse = oResponse || {};
                    oResponse.error = true;
                    YAHOO.util.DataSource.issueCallback(oCallback,[oRequest,oResponse],true, oCaller);

                    return null;
                };

                /**
                 * Define Connection Manager callback object
                 *
                 * @property _xhrCallback
                 * @param oResponse {Object} HTTPXMLRequest object
                 * @private
                 */
                 var _xhrCallback = {
                    success:_xhrSuccess,
                    failure:_xhrFailure,
                    scope: this
                };

                // Apply Connection Manager timeout
                if(YAHOO.lang.isNumber(this.connTimeout)) {
                    _xhrCallback.timeout = this.connTimeout;
                }

                // Cancel stale requests
                if(this.connXhrMode == "cancelStaleRequests") {
                        // Look in queue for stale requests
                        if(oQueue.conn) {
                            if(oConnMgr.abort) {
                                oConnMgr.abort(oQueue.conn);
                                oQueue.conn = null;
                                YAHOO.log("Canceled stale request", "warn", this.toString());
                            }
                            else {
                                YAHOO.log("Could not find Connection Manager abort() function", "error", this.toString());
                            }
                        }
                }

                // Get ready to send the request URL
                if(oConnMgr && oConnMgr.asyncRequest) {
                    var sLiveData = this.liveData;
                    var isPost = this.connMethodPost;
                    var sMethod = (isPost) ? "POST" : "GET";
                    var sUri = (isPost) ? sLiveData : sLiveData+oRequest;
                    var sRequest = (isPost) ? oRequest : null;

                    // Send the request right away
                    if(this.connXhrMode != "queueRequests") {
                        oQueue.conn = oConnMgr.asyncRequest(sMethod, sUri, _xhrCallback, sRequest);
                    }
                    // Queue up then send the request
                    else {
                        // Found a request already in progress
                        if(oQueue.conn) {
                            // Add request to queue
                            oQueue.requests.push({request:oRequest, callback:_xhrCallback});

                            // Interval needs to be started
                            if(!oQueue.interval) {
                                oQueue.interval = setInterval(function() {
                                    // Connection is in progress
                                    if(oConnMgr.isCallInProgress(oQueue.conn)) {
                                        return;
                                    }
                                    else {
                                        // Send next request
                                        if(oQueue.requests.length > 0) {
                                            sUri = (isPost) ? sLiveData : sLiveData+oQueue.requests[0].request;
                                            sRequest = (isPost) ? oQueue.requests[0].request : null;
                                            oQueue.conn = oConnMgr.asyncRequest(sMethod, sUri, oQueue.requests[0].callback, sRequest);

                                            // Remove request from queue
                                            oQueue.requests.shift();
                                        }
                                        // No more requests
                                        else {
                                            clearInterval(oQueue.interval);
                                            oQueue.interval = null;
                                        }
                                    }
                                }, 50);
                            }
                        }
                        // Nothing is in progress
                        else {
                            oQueue.conn = oConnMgr.asyncRequest(sMethod, sUri, _xhrCallback, sRequest);
                        }
                    }
                }
                else {
                    YAHOO.log("Could not find Connection Manager asyncRequest() function", "error", this.toString());
                    // Send null response back to the caller with the error flag on
                    YAHOO.util.DataSource.issueCallback(oCallback,[oRequest,{error:true}],true,oCaller);
                }

                break;
            // Simply forward the entire data object to the handler
            default:
                /* accounts for the following cases:
                YAHOO.util.DataSource.TYPE_UNKNOWN:
                YAHOO.util.DataSource.TYPE_JSARRAY:
                YAHOO.util.DataSource.TYPE_JSON:
                YAHOO.util.DataSource.TYPE_HTMLTABLE:
                YAHOO.util.DataSource.TYPE_XML:
                */
                oRawResponse = this.liveData;
                this.handleResponse(oRequest, oRawResponse, oCallback, oCaller, tId);
                break;
        }
        return tId;
    };

    /**
     * Receives raw data response and type converts to XML, JSON, etc as necessary.
     * Forwards oFullResponse to appropriate parsing function to get turned into
     * oParsedResponse. Calls doBeforeCallback() and adds oParsedResponse to
     * the cache when appropriate before calling issueCallback().
     *
     * The oParsedResponse object literal has the following properties:
     * <dl>
     *     <dd><dt>tId {Number}</dt> Unique transaction ID</dd>
     *     <dd><dt>results {Array}</dt> Array of parsed data results</dd>
     *     <dd><dt>error {Boolean}</dt> True if there was an error</dd>
     *     <dd><dt>totalRecords {Number}</dt> Total number of records (if available)</dd>
     * </dl>
     *
     * @method handleResponse
     * @param oRequest {Object} Request object
     * @param oRawResponse {Object} The raw response from the live database.
     * @param oCallback {Object} Callback object literal.
     * @param oCaller {Object} (deprecated) Use oCallback.scope.
     * @param tId {Number} Transaction ID.
     */
    YAHOO.util.DataSource.prototype.handleResponse = function(oRequest, oRawResponse, oCallback, oCaller, tId) {
        this.fireEvent("responseEvent", {request:oRequest, response:oRawResponse,
                callback:oCallback, caller:oCaller, tId: tId});
        YAHOO.log("Received live data response for \"" + oRequest + "\"", "info", this.toString());
        var xhr = (this.dataType == YAHOO.util.DataSource.TYPE_XHR) ? true : false;
        var oParsedResponse = null;
        var oFullResponse = oRawResponse;

        switch(this.responseType) {
            case YAHOO.util.DataSource.TYPE_JSARRAY:
                if(xhr && oRawResponse.responseText) {
                    oFullResponse = oRawResponse.responseText;
                }
                oFullResponse = this.doBeforeParseData(oRequest, oFullResponse);
                oParsedResponse = this.parseArrayData(oRequest, oFullResponse);
                break;
            case YAHOO.util.DataSource.TYPE_JSON:
                if(xhr && oRawResponse.responseText) {
                    oFullResponse = oRawResponse.responseText;
                }
                try {
                    // Convert to JSON object if it's a string
                    if(YAHOO.lang.isString(oFullResponse)) {
                        // Check for YUI JSON Util
                        if(YAHOO.lang.JSON) {
                            oFullResponse = YAHOO.lang.JSON.parse(oFullResponse);
                        }
                        // Look for JSON parsers using an API similar to json2.js
                        else if(window.JSON && JSON.parse) {
                            oFullResponse = JSON.parse(oFullResponse);
                        }
                        // Look for JSON parsers using an API similar to json.js
                        else if(oFullResponse.parseJSON) {
                            oFullResponse = oFullResponse.parseJSON();
                        }
                        // No JSON lib found so parse the string
                        else {
                            // Trim leading spaces
                            while (oFullResponse.length > 0 &&
                                    (oFullResponse.charAt(0) != "{") &&
                                    (oFullResponse.charAt(0) != "[")) {
                                oFullResponse = oFullResponse.substring(1, oFullResponse.length);
                            }

                            if(oFullResponse.length > 0) {
                                // Strip extraneous stuff at the end
                                var objEnd = Math.max(oFullResponse.lastIndexOf("]"),oFullResponse.lastIndexOf("}"));
                                oFullResponse = oFullResponse.substring(0,objEnd+1);

                                // Turn the string into an object literal...
                                // ...eval is necessary here
                                oFullResponse = eval("(" + oFullResponse + ")");

                            }
                        }
                    }
                }
                catch(e) {
                }

                oFullResponse = this.doBeforeParseData(oRequest, oFullResponse);
                oParsedResponse = this.parseJSONData(oRequest, oFullResponse);
                break;
            case YAHOO.util.DataSource.TYPE_HTMLTABLE:
                if(xhr && oRawResponse.responseText) {
                    oFullResponse = oRawResponse.responseText;
                }
                oFullResponse = this.doBeforeParseData(oRequest, oFullResponse);
                oParsedResponse = this.parseHTMLTableData(oRequest, oFullResponse);
                break;
            case YAHOO.util.DataSource.TYPE_XML:
                if(xhr && oRawResponse.responseXML) {
                    oFullResponse = oRawResponse.responseXML;
                }
                oFullResponse = this.doBeforeParseData(oRequest, oFullResponse);
                oParsedResponse = this.parseXMLData(oRequest, oFullResponse);
                break;
            case YAHOO.util.DataSource.TYPE_TEXT:
                if(xhr && oRawResponse.responseText) {
                    oFullResponse = oRawResponse.responseText;
                }
                oFullResponse = this.doBeforeParseData(oRequest, oFullResponse);
                oParsedResponse = this.parseTextData(oRequest, oFullResponse);
                break;
            default:
                //var contentType = oRawResponse.getResponseHeader["Content-Type"];
                YAHOO.log("Passing along unknown response type", "warn", this.toString());
                oFullResponse = this.doBeforeParseData(oRequest, oFullResponse);
                oParsedResponse = this.doBeforeParseData(oRequest, oFullResponse);
                break;
        }

        if(oParsedResponse && !oParsedResponse.error) {
            // Last chance to touch the raw response or the parsed response
            oParsedResponse = this.doBeforeCallback(oRequest, oFullResponse, oParsedResponse);
            this.fireEvent("responseParseEvent", {request:oRequest,
                    response:oParsedResponse, callback:oCallback, caller:oCaller});
            // Cache the response
            this.addToCache(oRequest, oParsedResponse);
        }
        else {
            this.fireEvent("dataErrorEvent", {request:oRequest, response: oRawResponse, callback:oCallback,
                    caller:oCaller, message:YAHOO.util.DataSource.ERROR_DATANULL});
            YAHOO.log(YAHOO.util.DataSource.ERROR_DATANULL, "error", this.toString());

            // Be sure the error flag is on
            oParsedResponse = oParsedResponse || {};
            oParsedResponse.error = true;
        }

        // Send the response back to the caller
        oParsedResponse.tId = tId;
        YAHOO.util.DataSource.issueCallback(oCallback,[oRequest,oParsedResponse],oParsedResponse.error,oCaller);
    };

    /**
     * Overridable method gives implementers access to the original full response
     * before the data gets parsed. Implementers should take care not to return an
     * unparsable or otherwise invalid response.
     *
     * @method doBeforeParseData
     * @param oRequest {Object} Request object.
     * @param oFullResponse {Object} The full response from the live database.
     * @return {Object} Full response for parsing.
     */
    YAHOO.util.DataSource.prototype.doBeforeParseData = function(oRequest, oFullResponse) {
        return oFullResponse;
    };

    /**
     * Overridable method gives implementers access to the original full response and
     * the parsed response (parsed against the given schema) before the data
     * is added to the cache (if applicable) and then sent back to callback function.
     * This is your chance to access the raw response and/or populate the parsed
     * response with any custom data.
     *
     * @method doBeforeCallback
     * @param oRequest {Object} Request object.
     * @param oFullResponse {Object} The full response from the live database.
     * @param oParsedResponse {Object} The parsed response to return to calling object.
     * @return {Object} Parsed response object.
     */
    YAHOO.util.DataSource.prototype.doBeforeCallback = function(oRequest, oFullResponse, oParsedResponse) {
        return oParsedResponse;
    };

    /**
     * Overridable method parses Array data into a response object.
     *
     * @method parseArrayData
     * @param oRequest {Object} Request object.
     * @param oFullResponse {Object} The full Array from the live database.
     * @return {Object} Parsed response object with the following properties:<br>
     *     - results (Array) Array of parsed data results<br>
     *     - error (Boolean) True if there was an error<br>
     *     - totalRecords (Number) Total number of records (if available)
     */
    YAHOO.util.DataSource.prototype.parseArrayData = function(oRequest, oFullResponse) {
        if(YAHOO.lang.isArray(oFullResponse)) {
            if(YAHOO.lang.isArray(this.responseSchema.fields)) {
                var results = [],
                    fields = this.responseSchema.fields,
                    i;
                for (i = fields.length - 1; i >= 0; --i) {
                    if (typeof fields[i] !== 'object') {
                        fields[i] = { key : fields[i] };
                    }
                }

                var parsers = {};
                for (i = fields.length - 1; i >= 0; --i) {
                    var p = fields[i].parser || fields[i].converter;
                    if (p) {
                        parsers[fields[i].key] = p;
                    }
                }

                var arrType = YAHOO.lang.isArray(oFullResponse[0]);
                for(i=oFullResponse.length-1; i>-1; i--) {
                    var oResult = {};
                    var rec = oFullResponse[i];
                    if (typeof rec === 'object') {
                        for(var j=fields.length-1; j>-1; j--) {
                            var field = fields[j];
                            var data = arrType ? rec[j] : rec[field.key];

                            if (parsers[field.key]) {
                                data = parsers[field.key].call(this,data);
                            }

                            // Safety measure
                            if(data === undefined) {
                                data = null;
                            }

                            oResult[field.key] = data;
                        }
                    }
                    results[i] = oResult;
                }

                var oParsedResponse = {results:results};
                YAHOO.log("Parsed array data is " +
                        YAHOO.lang.dump(oParsedResponse), "info", this.toString());
                return oParsedResponse;
            }
        }
        YAHOO.log("Array data could not be parsed: " + YAHOO.lang.dump(oFullResponse),
                "error", this.toString());
        return null;
    };

    /**
     * Overridable method parses plain text data into a response object.
     *
     * @method parseTextData
     * @param oRequest {Object} Request object.
     * @param oFullResponse {Object} The full text response from the live database.
     * @return {Object} Parsed response object with the following properties:<br>
     *     - results (Array) Array of parsed data results<br>
     *     - error (Boolean) True if there was an error<br>
     *     - totalRecords (Number) Total number of records (if available)
     */
    YAHOO.util.DataSource.prototype.parseTextData = function(oRequest, oFullResponse) {
        if(YAHOO.lang.isString(oFullResponse)) {
            if(YAHOO.lang.isArray(this.responseSchema.fields) &&
                    YAHOO.lang.isString(this.responseSchema.recordDelim) &&
                    YAHOO.lang.isString(this.responseSchema.fieldDelim)) {
                var oParsedResponse = {results:[]};
                var recDelim = this.responseSchema.recordDelim;
                var fieldDelim = this.responseSchema.fieldDelim;
                var fields = this.responseSchema.fields;
                if(oFullResponse.length > 0) {
                    // Delete the last line delimiter at the end of the data if it exists
                    var newLength = oFullResponse.length-recDelim.length;
                    if(oFullResponse.substr(newLength) == recDelim) {
                        oFullResponse = oFullResponse.substr(0, newLength);
                    }
                    // Split along record delimiter to get an array of strings
                    var recordsarray = oFullResponse.split(recDelim);
                    // Cycle through each record
                    for(var i = 0, len = recordsarray.length, recIdx = 0; i < len; ++i) {
                        var oResult = {};
                        var bError = false;
                        if (YAHOO.lang.isString(recordsarray[i])) {
                            // Split each record along field delimiter to get data array
                            var fielddataarray = recordsarray[i].split(fieldDelim);
                            for(var j=fields.length-1; j>-1; j--) {
                                try {
                                    // Remove quotation marks from edges, if applicable
                                    var data = fielddataarray[j];
                                    if (YAHOO.lang.isString(data)) {
                                        if(data.charAt(0) == "\"") {
                                            data = data.substr(1);
                                        }
                                        if(data.charAt(data.length-1) == "\"") {
                                            data = data.substr(0,data.length-1);
                                        }
                                        var field = fields[j];
                                        var key = (YAHOO.lang.isValue(field.key)) ? field.key : field;
                                        // Backward compatibility
                                        if(!field.parser && field.converter) {
                                            field.parser = field.converter;
                                            YAHOO.log("The field property converter has been deprecated" +
                                                    " in favor of parser", "warn", this.toString());
                                        }
                                        if(field.parser) {
                                            data = field.parser.call(this, data);
                                        }
                                        // Safety measure
                                        if(data === undefined) {
                                            data = null;
                                        }
                                        oResult[key] = data;
                                    }
                                    else {
                                        bError = true;
                                    }
                                }
                                catch(e) {
                                    bError = true;
                                }
                            }
                            if(!bError) {
                                oParsedResponse.results[recIdx++] = oResult;
                            }
                        }
                    }
                }
                YAHOO.log("Parsed text data is " +
                        YAHOO.lang.dump(oParsedResponse), "info", this.toString());
                return oParsedResponse;
            }
        }
        YAHOO.log("Text data could not be parsed: " + YAHOO.lang.dump(oFullResponse),
                "error", this.toString());
        return null;

    };

    /**
     * Overridable method parses XML data into a response object.
     *
     * @method parseXMLData
     * @param oRequest {Object} Request object.
     * @param oFullResponse {Object} The full XML response from the live database.
     * @return {Object} Parsed response object with the following properties<br>
     *     - results (Array) Array of parsed data results<br>
     *     - error (Boolean) True if there was an error<br>
     *     - totalRecords (Number) Total number of records (if available)
     */
    YAHOO.util.DataSource.prototype.parseXMLData = function(oRequest, oFullResponse) {
        var bError = false,
            schema = this.responseSchema,
            oParsedResponse = {meta:{}},
            xmlList = null,
            metaNode      = schema.metaNode,
            metaLocators  = schema.metaFields || {},
            totRecLocator = schema.totalRecords, // Back compat
            i,k,loc,v;

        if (totRecLocator && !metaLocators.totalRecords) {
            metaLocators.totalRecords = totRecLocator;
        }

        // In case oFullResponse is something funky
        try {
            xmlList = (schema.resultNode) ?
                oFullResponse.getElementsByTagName(schema.resultNode) :
                null;

            // Pull any meta identified
            metaNode = metaNode ? oFullResponse.getElementsByTagName(metaNode)[0] :
                       oFullResponse;

            if (metaNode) {
                for (k in metaLocators) {
                    if (YAHOO.lang.hasOwnProperty(metaLocators, k)) {
                        loc = metaLocators[k];
                        // Look for a node
                        v = metaNode.getElementsByTagName(loc)[0];

                        if (v) {
                            v = v.firstChild.nodeValue;
                        } else {
                            // Look for an attribute
                            v = metaNode.attributes.getNamedItem(loc);
                            if (v) {
                                v = v.value;
                            }
                        }

                        if (YAHOO.lang.isValue(v)) {
                            oParsedResponse.meta[k] = v;
                        }
                    }

                }
            }
        }
        catch(e) {
            YAHOO.log("Error while parsing XML data: " + e.message);
        }
        if(!xmlList || !YAHOO.lang.isArray(schema.fields)) {
            bError = true;
        }
        // Loop through each result
        else {

            oParsedResponse.results = [];
            for(i = xmlList.length-1; i >= 0 ; --i) {
                var result = xmlList.item(i);
                var oResult = {};
                // Loop through each data field in each result using the schema
                for(var m = schema.fields.length-1; m >= 0 ; m--) {
                    var field = schema.fields[m];
                    var key = (YAHOO.lang.isValue(field.key)) ? field.key : field;
                    var data = null;
                    // Values may be held in an attribute...
                    var xmlAttr = result.attributes.getNamedItem(key);
                    if(xmlAttr) {
                        data = xmlAttr.value;
                    }
                    // ...or in a node
                    else {
                        var xmlNode = result.getElementsByTagName(key);
                        if(xmlNode && xmlNode.item(0) && xmlNode.item(0).firstChild) {
                            data = xmlNode.item(0).firstChild.nodeValue;
                        }
                        else {
                               data = "";
                        }
                    }
                    // Backward compatibility
                    if(!field.parser && field.converter) {
                        field.parser = field.converter;
                        YAHOO.log("The field property converter has been deprecated" +
                                " in favor of parser", "warn", this.toString());
                    }
                    if(field.parser) {
                        data = field.parser.call(this, data);
                    }
                    // Safety measure
                    if(data === undefined) {
                        data = null;
                    }
                    oResult[key] = data;
                }
                // Capture each array of values into an array of results
                oParsedResponse.results[i] = oResult;
            }
        }
        if(bError) {
            YAHOO.log("XML data could not be parsed: " +
                    YAHOO.lang.dump(oFullResponse), "error", this.toString());
            oParsedResponse.error = true;
        }
        else {
            YAHOO.log("Parsed XML data is " +
                    YAHOO.lang.dump(oParsedResponse), "info", this.toString());
        }
        return oParsedResponse;
    };

    /**
     * Overridable method parses JSON data into a response object.
     *
     * @method parseJSONData
     * @param oRequest {Object} Request object.
     * @param oFullResponse {Object} The full JSON from the live database.
     * @return {Object} Parsed response object with the following properties<br>
     *     - results (Array) Array of parsed data results<br>
     *     - error (Boolean) True if there was an error<br>
     *     - totalRecords (Number) Total number of records (if available)
     */
    YAHOO.util.DataSource.prototype.parseJSONData = function(oRequest, oFullResponse) {
        var oParsedResponse = {results:[],meta:{}},
            schema          = this.responseSchema;

        if(YAHOO.lang.isObject(oFullResponse)) {
            if(YAHOO.lang.isArray(schema.fields)) {
                var fields          = schema.fields,
                    resultsList     = oFullResponse,
                    results         = [],
                    metaFields      = schema.metaFields || {},
                    fieldParsers    = [],
                    fieldPaths      = [],
                    simpleFields    = [],
                    bError          = false,
                    i,len,j,v,key,parser,path;

                // Function to parse the schema's locator keys into walk paths
                var buildPath = function (needle) {
                    var path = null, keys = [], i = 0;
                    if (needle) {
                        // Strip the ["string keys"] and [1] array indexes
                        needle = needle.
                            replace(/\[(['"])(.*?)\1\]/g,
                            function (x,$1,$2) {keys[i]=$2;return '.@'+(i++);}).
                            replace(/\[(\d+)\]/g,
                            function (x,$1) {keys[i]=parseInt($1,10)|0;return '.@'+(i++);}).
                            replace(/^\./,''); // remove leading dot

                        // If the cleaned needle contains invalid characters, the
                        // path is invalid
                        if (!/[^\w\.\$@]/.test(needle)) {
                            path = needle.split('.');
                            for (i=path.length-1; i >= 0; --i) {
                                if (path[i].charAt(0) === '@') {
                                    path[i] = keys[parseInt(path[i].substr(1),10)];
                                }
                            }
                        }
                    }
                    return path;
                };

                // build function to walk a path and return the pot of gold
                var walkPath = function (path, origin) {
                    var v=origin,i=0,len=path.length;
                    for (;i<len && v;++i) {
                        v = v[path[i]];
                    }
                    return v;
                };

                // Build the parser map and location paths
                for (i = fields.length - 1; i >= 0; --i) {
                    key    = fields[i].key || fields[i];
                    parser = fields[i].parser || fields[i].converter;
                    path   = buildPath(key);

                    if (parser) {
                        fieldParsers[fieldParsers.length] = {key:key,parser:parser};
                    }

                    if (path) {
                        if (path.length > 1) {
                            fieldPaths[fieldPaths.length] = {key:key,path:path};
                        } else {
                            simpleFields[simpleFields.length] = key;
                        }
                    } else {
                        YAHOO.log("Invalid key syntax: " + key,"warn",this.toString());
                    }
                }

                // Parse the response
                // Step 1. Pull the resultsList from oFullResponse (default assumes
                // oFullResponse IS the resultsList)
                if (schema.resultsList) {
                    path = buildPath(schema.resultsList);
                    if (path) {
                        resultsList = walkPath(path, oFullResponse);
                        if (resultsList === undefined) {
                            bError = true;
                        }
                    } else {
                        bError = true;
                    }
                }
                if (!resultsList) {
                    resultsList = [];
                }

                if (!YAHOO.lang.isArray(resultsList)) {
                    resultsList = [resultsList];
                }

                if (!bError) {
                    // Step 2. Process the results, flattening the records and/or
                    // applying parsers if needed
                    //if (fieldParsers.length || fieldPaths.length) {
                        for (i = resultsList.length - 1; i >= 0; --i) {
                            var r = resultsList[i], rec = {};
                            for (j = simpleFields.length - 1; j >= 0; --j) {
                                rec[simpleFields[j]] = r[simpleFields[j]];
                            }

                            for (j = fieldPaths.length - 1; j >= 0; --j) {
                                rec[fieldPaths[j].key] = walkPath(fieldPaths[j].path,r);
                            }

                            for (j = fieldParsers.length - 1; j >= 0; --j) {
                                var p = fieldParsers[j].key;
                                rec[p] = fieldParsers[j].parser(rec[p]);
                                if (rec[p] === undefined) {
                                    rec[p] = null;
                                }
                            }
                            results[i] = rec;
                        }
                    //}

                    // Step 3. Pull meta fields from oFullResponse if identified
                    if (schema.totalRecords && !metaFields.totalRecords) {
                        // for backward compatibility
                        metaFields.totalRecords = schema.totalRecords;
                    }

                    for (key in metaFields) {
                        if (YAHOO.lang.hasOwnProperty(metaFields,key)) {
                            path = buildPath(metaFields[key]);
                            if (path) {
                                v = walkPath(path, oFullResponse);
                                oParsedResponse.meta[key] = v;
                            }
                        }
                    }

                } else {
                    YAHOO.log("JSON data could not be parsed: " +
                            YAHOO.lang.dump(oFullResponse), "error", this.toString());

                    oParsedResponse.error = true;
                }

                oParsedResponse.results = results;
            }
        }
        else {
            YAHOO.log("JSON data could not be parsed: " +
                    YAHOO.lang.dump(oFullResponse), "error", this.toString());
            oParsedResponse.error = true;
        }

        return oParsedResponse;
    };

    /**
     * Overridable method parses an HTML TABLE element reference into a response object.
     *
     * @method parseHTMLTableData
     * @param oRequest {Object} Request object.
     * @param oFullResponse {Object} The full HTML element reference from the live database.
     * @return {Object} Parsed response object with the following properties<br>
     *     - results (Array) Array of parsed data results<br>
     *     - error (Boolean) True if there was an error<br>
     *     - totalRecords (Number) Total number of records (if available)
     */
    YAHOO.util.DataSource.prototype.parseHTMLTableData = function(oRequest, oFullResponse) {
        var bError = false;
        var elTable = oFullResponse;
        var fields = this.responseSchema.fields;
        var oParsedResponse = {results:[]};

        // Iterate through each TBODY
        for(var i=0; i<elTable.tBodies.length; i++) {
            var elTbody = elTable.tBodies[i];

            // Iterate through each TR
            for(var j=elTbody.rows.length-1; j>-1; j--) {
                var elRow = elTbody.rows[j];
                var oResult = {};

                for(var k=fields.length-1; k>-1; k--) {
                    var field = fields[k];
                    var key = (YAHOO.lang.isValue(field.key)) ? field.key : field;
                    var data = elRow.cells[k].innerHTML;

                    // Backward compatibility
                    if(!field.parser && field.converter) {
                        field.parser = field.converter;
                        YAHOO.log("The field property converter has been deprecated" +
                                " in favor of parser", "warn", this.toString());
                    }
                    if(field.parser) {
                        data = field.parser.call(this, data);
                    }
                    // Safety measure
                    if(data === undefined) {
                        data = null;
                    }
                    oResult[key] = data;
                }
                oParsedResponse.results[j] = oResult;
            }
        }

        if(bError) {
            YAHOO.log("HTML TABLE data could not be parsed: " +
                    YAHOO.lang.dump(oFullResponse), "error", this.toString());
            oParsedResponse.error = true;
        }
        else {
            YAHOO.log("Parsed HTML TABLE data is " +
                    YAHOO.lang.dump(oParsedResponse), "info", this.toString());
        }
        return oParsedResponse;
    };

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

    /**
     * The static Number class provides helper functions to deal with data of type
     * Number.
     *
     * @namespace YAHOO.util
     * @requires datasource
     * @class Number
     * @static
     */
     YAHOO.util.Number = {

         /**
         * Takes a native JavaScript Number and formats to string for display to user.
         *
         * @method format
         * @param nData {Number} Number.
         * @param oConfig {Object} (Optional) Optional configuration values:
         *  <dl>
         *   <dt>prefix {String}</dd>
         *   <dd>String prepended before each number, like a currency designator "$"</dd>
         *   <dt>decimalPlaces {Number}</dd>
         *   <dd>Number of decimal places to round.</dd>
         *   <dt>decimalSeparator {String}</dd>
         *   <dd>Decimal separator</dd>
         *   <dt>thousandsSeparator {String}</dd>
         *   <dd>Thousands separator</dd>
         *   <dt>suffix {String}</dd>
         *   <dd>String appended after each number, like " items" (note the space)</dd>
         *  </dl>
         * @return {String} Formatted number for display.
         */
        format: function(nData, oConfig) {
            oConfig = oConfig || {};

            if(!YAHOO.lang.isNumber(nData)) {
                nData *= 1;
            }

            if(YAHOO.lang.isNumber(nData)) {
                var sOutput = nData + "";
                var sDecimalSeparator = (oConfig.decimalSeparator) ? oConfig.decimalSeparator : ".";
                var nDotIndex;

                // Manage decimals
                if(YAHOO.lang.isNumber(oConfig.decimalPlaces)) {
                    // Round to the correct decimal place
                    var nDecimalPlaces = oConfig.decimalPlaces;
                    var nDecimal = Math.pow(10, nDecimalPlaces);
                    sOutput = Math.round(nData*nDecimal)/nDecimal + "";
                    nDotIndex = sOutput.lastIndexOf(".");

                    if(nDecimalPlaces > 0) {
                        // Add the decimal separator
                        if(nDotIndex < 0) {
                            sOutput += sDecimalSeparator;
                            nDotIndex = sOutput.length-1;
                        }
                        // Replace the "."
                        else if(sDecimalSeparator !== "."){
                            sOutput = sOutput.replace(".",sDecimalSeparator);
                        }
                        // Add missing zeros
                        while((sOutput.length - 1 - nDotIndex) < nDecimalPlaces) {
                            sOutput += "0";
                        }
                    }
                }

                // Add the thousands separator
                if(oConfig.thousandsSeparator) {
                    var sThousandsSeparator = oConfig.thousandsSeparator;
                    nDotIndex = sOutput.lastIndexOf(sDecimalSeparator);
                    nDotIndex = (nDotIndex > -1) ? nDotIndex : sOutput.length;
                    var sNewOutput = sOutput.substring(nDotIndex);
                    var nCount = -1;
                    for (var i=nDotIndex; i>0; i--) {
                        nCount++;
                        if ((nCount%3 === 0) && (i !== nDotIndex)) {
                            sNewOutput = sThousandsSeparator + sNewOutput;
                        }
                        sNewOutput = sOutput.charAt(i-1) + sNewOutput;
                    }
                    sOutput = sNewOutput;
                }

                // Prepend prefix
                sOutput = (oConfig.prefix) ? oConfig.prefix + sOutput : sOutput;

                // Append suffix
                sOutput = (oConfig.suffix) ? sOutput + oConfig.suffix : sOutput;

                return sOutput;
            }
            // Still not a Number, just return unaltered
            else {
                return nData;
            }
        }
     };

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

    /**
     * The static Date class provides helper functions to deal with data of type
     * Number.
     *
     * @namespace YAHOO.util
     * @requires datasource
     * @class Date
     * @static
     */
     YAHOO.util.Date = {
         /**
         * Takes a native JavaScript Date and formats to string for display to user.
         *
         * @method format
         * @param oDate {Date} Date.
         * @param oConfig {Object} (Optional) Optional configuration values:
         *  <dl>
         *   <dt>format {String}</dd>
         *   <dd>Currently only the following formats are supported:
         *   "MM/DD/YYYY", "YYYY/MM/DD", or "DD/MM/YYYY"</dd>
         *  </dl>
         * @return {String} Formatted date for display.
         */
        format: function(oDate, oConfig) {
            oConfig = oConfig || {};

            if(oDate instanceof Date) {
                var format = oConfig.format || "MM/DD/YYYY";
                var mm = oDate.getMonth()+1;
                var dd = oDate.getDate();
                var yyyy = oDate.getFullYear();

                switch(format) {
                    case "YYYY/MM/DD":
                        return yyyy + "/" + mm +"/" + dd;
                    case "DD/MM/YYYY":
                        return dd + "/" + mm + "/" + yyyy;
                    default: // "MM/DD/YYYY"
                        return mm + "/" + dd + "/" + yyyy;
                }
            }
            else {
                return YAHOO.lang.isValue(oDate) ? oDate : "";
            }
        }
     };

Copyright © 2007 Yahoo! Inc. All rights reserved.