/**
* @class YAHOO.ext.grid.LoadableDataModel
* This class extends DefaultDataModel and adds the core functionality to load data remotely. Generally you will want to use one of it's subclasses.<br><br>
* @extends YAHOO.ext.grid.DefaultDataModel
* @constructor
* @param {String} dataType YAHOO.ext.grid.LoadableDataModel.XML, YAHOO.ext.grid.LoadableDataModel.TEXT or YAHOO.ext.grid.JSON
*/
YAHOO.ext.grid.LoadableDataModel = function(dataType){
YAHOO.ext.grid.LoadableDataModel.superclass.constructor.call(this, []);
/** Fires when a successful load is completed - fireDirect sig: (this)
* @type YAHOO.util.CustomEvent
* @deprecated Use addListener instead of accessing directly
* @private
*/
this.onLoad = new YAHOO.util.CustomEvent('load');
/** Fires when a load fails - fireDirect sig: (this, errorMsg, responseObj)
* @type YAHOO.util.CustomEvent
* @deprecated Use addListener instead of accessing directly
* @private
*/
this.onLoadException = new YAHOO.util.CustomEvent('loadException');
/**
* @event load
* Fires when new data has successfully been loaded
* @param {DataModel} this
*/
this.events['load'] = this.onLoad;
/**
* @event beforeload
* Fires before a load takes place
* @param {DataModel} this
*/
this.events['beforeload'] = new YAHOO.util.CustomEvent('beforeload');
/**
* @event loadexception
* Fires when there's an error loading data
* @param {DataModel} this
* @param {Exception} e The exception object or null
* @param {Object} response The Connect response object
*/
this.events['loadexception'] = this.onLoadException;
/**@private*/
this.dataType = dataType;
/**@private*/
this.preprocessors = [];
/**@private*/
this.postprocessors = [];
// paging info
/** The active page @type Number*/
this.loadedPage = 1;
/** True to use remote sorting, initPaging automatically sets this to true @type Boolean */
this.remoteSort = false;
/** The number of records per page @type Number*/
this.pageSize = 0;
/** The script/page to call to provide paged/sorted data @type String*/
this.pageUrl = null;
/** An object of key/value pairs to be passed as parameters
* when loading pages/sorting @type Object*/
this.baseParams = {};
/** Maps named params to url parameters - Override to specify your own param names */
this.paramMap = {'page':'page', 'pageSize':'pageSize', 'sortColumn':'sortColumn', 'sortDir':'sortDir'};
};
YAHOO.extendX(YAHOO.ext.grid.LoadableDataModel, YAHOO.ext.grid.DefaultDataModel, {
/** @ignore */
setLoadedPage: function(pageNum, userCallback){
this.loadedPage = pageNum;
if(typeof userCallback == 'function'){
userCallback();
}
},
/** Returns true if this model uses paging @return Boolean */
isPaged: function(){
return this.pageSize > 0;
},
/** Returns the total number of records available, override if needed @return {Number} */
getTotalRowCount: function(){
return this.totalCount || this.getRowCount();
},
/** Returns the number of records per page @return Number */
getPageSize: function(){
return this.pageSize;
},
/** Returns the total number of pages available @return Number */
getTotalPages: function(){
if(this.getPageSize() == 0 || this.getTotalRowCount() == 0){
return 1;
}
return Math.ceil(this.getTotalRowCount()/this.getPageSize());
},
/** Initializes paging for this model.
* @param {String} url
* @param {Number} pageSize
* @param {Object} baseParams (optional) Object containing key/value pairs to add to all requests
*/
initPaging: function(url, pageSize, baseParams){
this.pageUrl = url;
this.pageSize = pageSize;
this.remoteSort = true;
if(baseParams) this.baseParams = baseParams;
},
/** @ignore */
createParams: function(pageNum, sortColumn, sortDir){
var params = {}, map = this.paramMap;
for(var key in this.baseParams){
if(typeof this.baseParams[key] != 'function'){
params[key] = this.baseParams[key];
}
}
params[map['page']] = pageNum;
params[map['pageSize']] = this.getPageSize();
params[map['sortColumn']] = (typeof sortColumn == 'undefined' ? '' : sortColumn);
params[map['sortDir']] = sortDir || '';
return params;
},
/**
* Loads a page of data.
* @param {Number} pageNum Which page to load. The first page is 1.
* @param {Function} callback (optional) Optional callback when loading is complete
* @param {Boolean} keepExisting (optional) true to keep existing data and append the new data
*/
loadPage: function(pageNum, callback, keepExisting){
var sort = this.getSortState();
var params = this.createParams(pageNum, sort.column, sort.direction);
this.load(this.pageUrl, params, this.setLoadedPage.createDelegate(this, [pageNum, callback]),
keepExisting ? (pageNum-1) * this.pageSize : null);
},
/** @ignore */
applySort: function(suppressEvent){
if(!this.remoteSort){
YAHOO.ext.grid.LoadableDataModel.superclass.applySort.apply(this, arguments);
}else if(!suppressEvent){
var sort = this.getSortState();
if(sort.column){
this.fireRowsSorted(sort.column, sort.direction, true);
}
}
},
/** @ignore */
resetPaging: function(){
this.loadedPage = 1;
},
/* Overridden sort method to use remote sorting if turned on */
sort: function(sortInfo, columnIndex, direction, suppressEvent){
if(!this.remoteSort){
YAHOO.ext.grid.LoadableDataModel.superclass.sort.apply(this, arguments);
}else{
this.sortInfo = sortInfo;
this.sortColumn = columnIndex;
this.sortDir = direction;
var params = this.createParams(this.loadedPage, columnIndex, direction);
this.load(this.pageUrl, params, this.fireRowsSorted.createDelegate(this, [columnIndex, direction, true]));
}
},
/**
* Initiates the loading of the data from the specified URL - Failed load attempts will
* fire the {@link #loadexception} event.
* @param {Object/String} url The url from which the data can be loaded
* @param {<i>String/Object</i>} params (optional) The parameters to pass as either a url encoded string "param1=1&param2=2" or as an object {param1: 1, param2: 2}
* @param {<i>Function</i>} callback (optional) Callback when load is complete - called with signature (this, true for success, false for failure)
* @param {<i>Number</i>} insertIndex (optional) if present, loaded data is inserted at the specified index instead of overwriting existing data
*/
load: function(url, params, callback, insertIndex){
this.fireEvent('beforeload', this);
if(params && typeof params != 'string'){ // must be object
var buf = [];
for(var key in params){
if(typeof params[key] != 'function'){
buf.push(encodeURIComponent(key), '=', encodeURIComponent(params[key]), '&');
}
}
delete buf[buf.length-1];
params = buf.join('');
}
var cb = {
success: this.processResponse,
failure: this.processException,
scope: this,
argument: {callback: callback, insertIndex: insertIndex}
};
var method = params ? 'POST' : 'GET';
this.transId = YAHOO.util.Connect.asyncRequest(method, url, cb, params);
},
/**@private*/
processResponse: function(response){
var cb = response.argument.callback;
var keepExisting = (typeof response.argument.insertIndex == 'number');
var insertIndex = response.argument.insertIndex;
switch(this.dataType){
case YAHOO.ext.grid.LoadableDataModel.XML:
this.loadData(response.responseXML, cb, keepExisting, insertIndex);
break;
case YAHOO.ext.grid.LoadableDataModel.JSON:
var rtext = response.responseText;
try { // this code is a modified version of Yahoo! UI DataSource JSON parsing
// Trim leading spaces
while(rtext.substring(0,1) == " ") {
rtext = rtext.substring(1, rtext.length);
}
// Invalid JSON response
if(rtext.indexOf("{") < 0) {
throw "Invalid JSON response";
}
// Empty (but not invalid) JSON response
if(rtext.indexOf("{}") === 0) {
this.loadData({}, response.argument.callback);
return;
}
// Turn the string into an object literal...
// ...eval is necessary here
var jsonObjRaw = eval("(" + rtext + ")");
if(!jsonObjRaw) {
throw "Error evaling JSON response";
}
this.loadData(jsonObjRaw, cb, keepExisting, insertIndex);
} catch(e) {
this.fireLoadException(e, response);
if(typeof cb == 'function'){
cb(this, false);
}
}
break;
case YAHOO.ext.grid.LoadableDataModel.TEXT:
this.loadData(response.responseText, cb, keepExisting, insertIndex);
break;
};
},
/**@private*/
processException: function(response){
this.fireLoadException(null, response);
if(typeof response.argument.callback == 'function'){
response.argument.callback(this, false);
}
},
fireLoadException: function(e, responseObj){
this.onLoadException.fireDirect(this, e, responseObj);
},
fireLoadEvent: function(){
this.fireEvent('load', this.loadedPage, this.getTotalPages());
},
/**
* Adds a preprocessor function to parse data before it is added to the Model - ie. Date.parse to parse dates.
* @param {Number} columnIndex
* @param {Function} fn
*/
addPreprocessor: function(columnIndex, fn){
this.preprocessors[columnIndex] = fn;
},
/**
* Gets the preprocessor function for the specified column.
* @param {Number} columnIndex
* @return {Function}
*/
getPreprocessor: function(columnIndex){
return this.preprocessors[columnIndex];
},
/**
* Removes a preprocessor function.
* @param {Number} columnIndex
*/
removePreprocessor: function(columnIndex){
this.preprocessors[columnIndex] = null;
},
/**
* Adds a postprocessor function to format data before updating the underlying data source (ie. convert date to string before updating XML document).
* @param {Number} columnIndex
* @param {Function} fn
*/
addPostprocessor: function(columnIndex, fn){
this.postprocessors[columnIndex] = fn;
},
/**
* Gets the postprocessor function for the specified column.
* @param {Number} columnIndex
* @return {Function}
*/
getPostprocessor: function(columnIndex){
return this.postprocessors[columnIndex];
},
/**
* Removes a postprocessor function.
* @param {Number} columnIndex
*/
removePostprocessor: function(columnIndex){
this.postprocessors[columnIndex] = null;
},
/**
* Empty interface method - Called to process the data returned by the XHR - Classes which extend LoadableDataModel should implement this method.
* See {@link YAHOO.ext.XMLDataModel} for an example implementation.
*/
loadData: function(data, callback, keepExisting, insertIndex){
}
});
YAHOO.ext.grid.LoadableDataModel.XML = 'xml';
YAHOO.ext.grid.LoadableDataModel.JSON = 'json';
YAHOO.ext.grid.LoadableDataModel.TEXT = 'text';