text: /*
   * Licensed to the Apache Software Foundation (ASF) under one
   * or more contributor license agreements. See the NOTICE file
   * distributed with this work for additional information
   * regarding copyright ownership. The ASF licenses this file
   * to you under the Apache License, Version 2.0 (the
   * "License"); you may not use this file except in compliance
   * with the License. You may obtain a copy of the License at
   *
   * http://www.apache.org/licenses/LICENSE-2.0
   *
   * Unless required by applicable law or agreed to in writing,
   * software distributed under the License is distributed on an
   * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
   * KIND, either express or implied. See the License for the
   * specific language governing permissions and limitations
   * under the License.
   */
  /**
   * 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) {
      // 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];
              }
          }
      }
      
      if(!oLiveData) {
          YAHOO.log("Could not instantiate DataSource due to invalid live database",
                  "error", this.toString());
          return;
      }
  
      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;
      }
      else if(YAHOO.lang.isObject(oLiveData)) {
          this.dataType = YAHOO.util.DataSource.TYPE_JSON;
      }
      else {
          this.dataType = YAHOO.util.DataSource.TYPE_UNKNOWN;
      }
  
      this.liveData = oLiveData;
      this._oQueue = {interval:null, conn:null, requests:[]};
  
  
      // Validate and initialize public configs
      var maxCacheEntries = this.maxCacheEntries;
      if(!YAHOO.lang.isNumber(maxCacheEntries) || (maxCacheEntries < 0)) {
          maxCacheEntries = 0;
      }
  
      // Initialize local cache
      if(maxCacheEntries > 0 && !this._aCache) {
          this._aCache = [];
          YAHOO.log("Cache initialized", "info", this.toString());
      }
  
      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} The parent object of the callback function.
       */
      this.createEvent("cacheRequestEvent");
  
      /**
       * Fired when data is retrieved from the local cache.
       *
       * @event getCachedResponseEvent
       * @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} The parent object of the callback function.
       * @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} The parent object of the callback function.
       */
      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} The parent object of the callback function.
       */
      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} The parent object of the callback function.
       */
      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} The parent object of the callback function.
       */
      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} The parent object of the callback function.
       * @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;
  
  /////////////////////////////////////////////////////////////////////////////
  //
  // 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>
   * </dl>
   *
   * @property responseSchema
   * @type Object
   */
  YAHOO.util.DataSource.prototype.responseSchema = null;
  
   /**
   * Alias to YUI Connection Manager. Allows implementers to specify their own
   * subclasses of the YUI Connection Manager 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;
      var nCacheLength = (aCache) ? aCache.length : 0;
      var oResponse = null;
  
      // If cache is enabled...
      if((this.maxCacheEntries > 0) && aCache && (nCacheLength > 0)) {
          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)) {
                  // Grab the cached response
                  oResponse = oCacheElem.response;
                  // The cache returned a hit!
                  // Remove element from its original location
                  aCache.splice(i,1);
                  // Add as newest
                  this.addToCache(oRequest, oResponse);
                  this.fireEvent("cacheResponseEvent", {request:oRequest,response:oResponse,callback:oCallback,caller:oCaller});
                  break;
              }
          }
      }
      YAHOO.log("The cached response for \"" + YAHOO.lang.dump(oRequest) +
              "\" is " + YAHOO.lang.dump(oResponse), "info", this.toString());
      return oResponse;
  };
  
  /**
   * 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;
      }
  
      //TODO: check for duplicate entries
  
      // 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.push(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());
      }
  };
  
  /**
   * First looks for cached response, then sends request to live data.
   *
   * @method sendRequest
   * @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 {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) {
          oCallback.call(oCaller, oRequest, oCachedResponse);
          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 {Function} Handler function to receive the response.
   * @param oCaller {Object} The Calling object that is making the request.
   * @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
                      oCallback.call(oCaller, oRequest, oResponse, true);
  
                      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
                  oCallback.call(oCaller, oRequest, oResponse, true);
                  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
                  oCallback.call(oCaller, oRequest, null, true);
              }
  
              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;
  };
  
  /**
   * Handles raw data response from live data source. Sends a parsed response object
   * to the callback function in this format:
   *
   * fnCallback(oRequest, oParsedResponse)
   *
   * where the oParsedResponse object literal with the following properties:
   * <ul>
   *     <li>tId {Number} Unique transaction ID</li>
   *     <li>results {Array} Array of parsed data results</li>
   *     <li>error {Boolean} True if there was an error</li>
   * </ul>
   *
   * @method handleResponse
   * @param oRequest {Object} Request object
   * @param oRawResponse {Object} The raw response from the live database.
   * @param oCallback {Function} Handler function to receive the response.
   * @param oCaller {Object} The calling object that is making the request.
   * @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 bError = false;
  
      // Access to the raw response before it gets parsed
      oRawResponse = this.doBeforeParseData(oRequest, oRawResponse);
  
      switch(this.responseType) {
          case YAHOO.util.DataSource.TYPE_JSARRAY:
              if(xhr && oRawResponse.responseText) {
                  oRawResponse = oRawResponse.responseText;
              }
              oParsedResponse = this.parseArrayData(oRequest, oRawResponse);
              break;
          case YAHOO.util.DataSource.TYPE_JSON:
              if(xhr && oRawResponse.responseText) {
                  oRawResponse = oRawResponse.responseText;
              }
              oParsedResponse = this.parseJSONData(oRequest, oRawResponse);
              break;
          case YAHOO.util.DataSource.TYPE_HTMLTABLE:
              if(xhr && oRawResponse.responseText) {
                  oRawResponse = oRawResponse.responseText;
              }
              oParsedResponse = this.parseHTMLTableData(oRequest, oRawResponse);
              break;
          case YAHOO.util.DataSource.TYPE_XML:
              if(xhr && oRawResponse.responseXML) {
                  oRawResponse = oRawResponse.responseXML;
              }
              oParsedResponse = this.parseXMLData(oRequest, oRawResponse);
              break;
          case YAHOO.util.DataSource.TYPE_TEXT:
              if(xhr && oRawResponse.responseText) {
                  oRawResponse = oRawResponse.responseText;
              }
              oParsedResponse = this.parseTextData(oRequest, oRawResponse);
              break;
          default:
              //var contentType = oRawResponse.getResponseHeader["Content-Type"];
              YAHOO.log("Could not parse data for request \"" + oRequest +
                      "\" due to unknown response type", "error", this.toString());
              break;
      }
  
  
      if(oParsedResponse) {
          // Last chance to touch the raw response or the parsed response
          oParsedResponse.tId = tId;
          oParsedResponse = this.doBeforeCallback(oRequest, oRawResponse, 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, callback:oCallback,
                  caller:oCaller, message:YAHOO.util.DataSource.ERROR_DATANULL});
          YAHOO.log(YAHOO.util.DataSource.ERROR_DATANULL, "error", this.toString());
          
          // Send response back to the caller with the error flag on
          oParsedResponse = {error:true};
      }
      
      // Send the response back to the caller
      oCallback.call(oCaller, oRequest, oParsedResponse);
  };
  
  /**
   * Overridable method gives implementers access to the original raw response
   * before the data gets parsed. Implementers should take care not to return an
   * unparsable or otherwise invalid raw response.
   *
   * @method doBeforeParseData
   * @param oRequest {Object} Request object.
   * @param oRawResponse {Object} The raw response from the live database.
   * @return {Object} Raw response for parsing.
   */
  YAHOO.util.DataSource.prototype.doBeforeParseData = function(oRequest, oRawResponse) {
      return oRawResponse;
  };
  
  /**
   * Overridable method gives implementers access to the original raw 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 oRawResponse {Object} The raw 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, oRawResponse, oParsedResponse) {
      return oParsedResponse;
  };
  
  /**
   * Overridable method parses raw array data into a response object.
   *
   * @method parseArrayData
   * @param oRequest {Object} Request object.
   * @param oRawResponse {Object} The raw response from the live database.
   * @return {Object} Parsed response object.
   */
  YAHOO.util.DataSource.prototype.parseArrayData = function(oRequest, oRawResponse) {
      if(YAHOO.lang.isArray(oRawResponse) && YAHOO.lang.isArray(this.responseSchema.fields)) {
          var oParsedResponse = {results:[]};
          var fields = this.responseSchema.fields;
          for(var i=oRawResponse.length-1; i>-1; i--) {
              var oResult = {};
              for(var j=fields.length-1; j>-1; j--) {
                  var field = fields[j];
                  var key = (YAHOO.lang.isValue(field.key)) ? field.key : field;
                  var data = (YAHOO.lang.isValue(oRawResponse[i][j])) ? oRawResponse[i][j] : oRawResponse[i][key];
                  // 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.unshift(oResult);
          }
          YAHOO.log("Parsed array data is " +
                  YAHOO.lang.dump(oParsedResponse), "info", this.toString());
          return oParsedResponse;
      }
      else {
          YAHOO.log("Array data could not be parsed: " +
                  YAHOO.lang.dump(oRawResponse), "error", this.toString());
          return null;
      }
  };
  
  /**
   * Overridable method parses raw plain text data into a response object.
   *
   * @method parseTextData
   * @param oRequest {Object} Request object.
   * @param oRawResponse {Object} The raw response from the live database.
   * @return {Object} Parsed response object.
   */
  YAHOO.util.DataSource.prototype.parseTextData = function(oRequest, oRawResponse) {
      var oParsedResponse = {};
      if(YAHOO.lang.isString(oRawResponse) &&
              YAHOO.lang.isArray(this.responseSchema.fields) &&
              YAHOO.lang.isString(this.responseSchema.recordDelim) &&
              YAHOO.lang.isString(this.responseSchema.fieldDelim)) {
          oParsedResponse.results = [];
          var recDelim = this.responseSchema.recordDelim;
          var fieldDelim = this.responseSchema.fieldDelim;
          var fields = this.responseSchema.fields;
          if(oRawResponse.length > 0) {
              // Delete the last line delimiter at the end of the data if it exists
              var newLength = oRawResponse.length-recDelim.length;
              if(oRawResponse.substr(newLength) == recDelim) {
                  oRawResponse = oRawResponse.substr(0, newLength);
              }
              // Split along record delimiter to get an array of strings
              var recordsarray = oRawResponse.split(recDelim);
              // Cycle through each record, except the first which contains header info
              for(var i = recordsarray.length-1; i>-1; i--) {
                  var oResult = {};
                  for(var j=fields.length-1; j>-1; j--) {
                      // Split along field delimter to get each data value
                      var fielddataarray = recordsarray[i].split(fieldDelim);
  
                      // Remove quotation marks from edges, if applicable
                      var data = fielddataarray[j];
                      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;
                  }
                  oParsedResponse.results.unshift(oResult);
              }
          }
          YAHOO.log("Parsed text data is " +
                  YAHOO.lang.dump(oParsedResponse), "info", this.toString());
      }
      else {
          YAHOO.log("Text data could not be parsed: " +
                  YAHOO.lang.dump(oRawResponse), "error", this.toString());
          oParsedResponse.error = true;
      }
      return oParsedResponse;
  };
  
  /**
   * Overridable method parses raw XML data into a response object.
   *
   * @method parseXMLData
   * @param oRequest {Object} Request object.
   * @param oRawResponse {Object} The raw response from the live database.
   * @return {Object} Parsed response object.
   */
  YAHOO.util.DataSource.prototype.parseXMLData = function(oRequest, oRawResponse) {
          var bError = false;
          var oParsedResponse = {};
          var xmlList = (this.responseSchema.resultNode) ?
                  oRawResponse.getElementsByTagName(this.responseSchema.resultNode) :
                  null;
          if(!xmlList || !YAHOO.lang.isArray(this.responseSchema.fields)) {
              bError = true;
          }
          // Loop through each result
          else {
              oParsedResponse.results = [];
              for(var k = xmlList.length-1; k >= 0 ; k--) {
                  var result = xmlList.item(k);
                  var oResult = {};
                  // Loop through each data field in each result using the schema
                  for(var m = this.responseSchema.fields.length-1; m >= 0 ; m--) {
                      var field = this.responseSchema.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.unshift(oResult);
              }
          }
          if(bError) {
              YAHOO.log("XML data could not be parsed: " +
                      YAHOO.lang.dump(oRawResponse), "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 raw JSON data into a response object.
   *
   * @method parseJSONData
   * @param oRequest {Object} Request object.
   * @param oRawResponse {Object} The raw response from the live database.
   * @return {Object} Parsed response object.
   */
  YAHOO.util.DataSource.prototype.parseJSONData = function(oRequest, oRawResponse) {
      var oParsedResponse = {};
      if(oRawResponse && YAHOO.lang.isArray(this.responseSchema.fields)) {
          var fields = this.responseSchema.fields;
          var bError = false;
          oParsedResponse.results = [];
          var jsonObj,jsonList;
  
          // Parse JSON object out if it's a string
          if(YAHOO.lang.isString(oRawResponse)) {
              // Check for latest JSON lib but divert KHTML clients
              var isNotMac = (navigator.userAgent.toLowerCase().indexOf('khtml')== -1);
              if(oRawResponse.parseJSON && isNotMac) {
                  // Use the new JSON utility if available
                  jsonObj = oRawResponse.parseJSON();
                  if(!jsonObj) {
                      bError = true;
                  }
              }
              // Check for older JSON lib but divert KHTML clients
              else if(window.JSON && JSON.parse && isNotMac) {
                  // Use the JSON utility if available
                  jsonObj = JSON.parse(oRawResponse);
                  if(!jsonObj) {
                      bError = true;
                  }
              }
              // No JSON lib found so parse the string
              else {
                  try {
                      // Trim leading spaces
                      while (oRawResponse.length > 0 &&
                              (oRawResponse.charAt(0) != "{") &&
                              (oRawResponse.charAt(0) != "[")) {
                          oRawResponse = oRawResponse.substring(1, oRawResponse.length);
                      }
  
                      if(oRawResponse.length > 0) {
                          // Strip extraneous stuff at the end
                          var objEnd = Math.max(oRawResponse.lastIndexOf("]"),oRawResponse.lastIndexOf("}"));
                          oRawResponse = oRawResponse.substring(0,objEnd+1);
  
                          // Turn the string into an object literal...
                          // ...eval is necessary here
                          jsonObj = eval("(" + oRawResponse + ")");
                          if(!jsonObj) {
                              bError = true;
                          }
  
                      }
                      else {
                          jsonObj = null;
                          bError = true;
                      }
                  }
                  catch(e) {
                      bError = true;
                 }
              }
          }
          // Response must already be a JSON object
          else if(oRawResponse.constructor == Object) {
              jsonObj = oRawResponse;
          }
          // Not a string or an object
          else {
              bError = true;
          }
          // Now that we have a JSON object, parse a jsonList out of it
          if(jsonObj && jsonObj.constructor == Object) {
              try {
                  // eval is necessary here since schema can be of unknown depth
                  jsonList = eval("jsonObj." + this.responseSchema.resultsList);
              }
              catch(e) {
                  bError = true;
              }
          }
  
          if(bError || !jsonList) {
              YAHOO.log("JSON data could not be parsed: " +
                      YAHOO.lang.dump(oRawResponse), "error", this.toString());
              oParsedResponse.error = true;
          }
          if(jsonList && !YAHOO.lang.isArray(jsonList)) {
              jsonList = [jsonList];
          }
          else if(!jsonList) {
              jsonList = [];
          }
  
          // Loop through the array of all responses...
          for(var i = jsonList.length-1; i >= 0 ; i--) {
              var oResult = {};
              var jsonResult = jsonList[i];
              // ...and loop through each data field value of each response
              for(var j = fields.length-1; j >= 0 ; j--) {
                  var field = fields[j];
                  var key = (YAHOO.lang.isValue(field.key)) ? field.key : field;
                  // ...and capture data into an array mapped according to the schema...
                  // eval is necessary here since schema can be of unknown depth
                  var data = eval("jsonResult." + key);
                  //YAHOO.log("data: " + i + " value:" +j+" = "+dataFieldValue,"debug",this.toString());
                  
                  // 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 the array of data field values in an array of results
              oParsedResponse.results.unshift(oResult);
          }
          YAHOO.log("Parsed JSON data is " +
                  YAHOO.lang.dump(oParsedResponse), "info", this.toString());
      }
      else {
          YAHOO.log("JSON data could not be parsed: " +
                  YAHOO.lang.dump(oRawResponse), "error", this.toString());
          oParsedResponse.error = true;
      }
      return oParsedResponse;
  };
  
  /**
   * Overridable method parses raw HTML TABLE element data into a response object.
   *
   * @method parseHTMLTableData
   * @param oRequest {Object} Request object.
   * @param oRawResponse {Object} The raw response from the live database.
   * @return {Object} Parsed response object.
   */
  YAHOO.util.DataSource.prototype.parseHTMLTableData = function(oRequest, oRawResponse) {
          var bError = false;
          var elTable = oRawResponse;
          var fields = this.responseSchema.fields;
          var oParsedResponse = {};
          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.unshift(oResult);
              }
          }
  
          if(bError) {
              YAHOO.log("HTML TABLE data could not be parsed: " +
                      YAHOO.lang.dump(oRawResponse), "error", this.toString());
              oParsedResponse.error = true;
          }
          else {
              YAHOO.log("Parsed HTML TABLE data is " +
                      YAHOO.lang.dump(oParsedResponse), "info", this.toString());
          }
          return oParsedResponse;
  };
  
  YAHOO.register("datasource", YAHOO.util.DataSource, {version: "2.3.1", build: "541"});
  