Subversion Repositories Applications.papyrus

if(!dojo._hasResource["dojox.data.demos.stores.LazyLoadJSIStore"]){ //_hasResource checks added by build. Do not use _hasResource directly in your code.

dojo._hasResource["dojox.data.demos.stores.LazyLoadJSIStore"] = true;

dojo.provide("dojox.data.demos.stores.LazyLoadJSIStore");

dojo.require("dojo.data.ItemFileReadStore");

dojo.declare("dojox.data.demos.stores.LazyLoadJSIStore", dojo.data.ItemFileReadStore, {

	constructor: function(/* object */ keywordParameters){

		// LazyLoadJSIStore extends ItemFileReadStore to implement an

		// example of lazy-loading/faulting in items on-demand.

		// Note this is certianly not a perfect implementation, it is

		// an example.

	},

	isItemLoaded: function(/*object*/ item) {

		//	summary:

		//		Overload of the isItemLoaded function to look for items of type 'stub', which indicate

		//		the data hasn't been loaded in yet.

		//

		//	item:

		//		The item to examine.

		//For this store, if it has the value of stub for its type attribute,

		//then the item basn't been fully loaded yet.  It's just a placeholder.

		if(this.getValue(item, "type") === "stub"){

			return false;

		}

		return true;

	},

	loadItem: function(keywordArgs){

		//	summary:

		//		Overload of the loadItem function to fault in items.  This assumes the data for an item is laid out

		//		in a RESTful sort of pattern name0/name1/data.json and so on and uses that to load the data.

		//		It will also detect stub items in the newly loaded item and insert the stubs into the ItemFileReadStore

		//		list so they can also be loaded in on-demand.

		//

		//	item:

		//		The item to examine.

		var item = keywordArgs.item;

		this._assertIsItem(item);

		//Build the path to the data.json for this item

		//The path consists of where its parent was loaded from

		//plus the item name.

		var itemName = this.getValue(item, "name");

		var parent   = this.getValue(item, "parent");

		var dataUrl  = "";

		if (parent){

			dataUrl += (parent + "/");

		}

		//For this store, all child input data is loaded from a url that ends with data.json

		dataUrl += itemName + "/data.json";

		//Need a reference to the store to call back to its structures.

		var self = this;

		// Callback for handling a successful load.

		var gotData = function(data){

			//Now we need to modify the existing item a bit to take it out of stub state

			//Since we extend the store and have knowledge of the internal

			//structure, this can be done here.  Now, is we extended

			//a write store, we could call the write APIs to do this too

			//But for a simple demo the diretc modification in the store function

			//is sufficient.

			//Clear off the stub indicators.

			delete item.type;

			delete item.parent;

			//Set up the loaded values in the format ItemFileReadStore uses for attributes.

			for (i in data) {

				if (dojo.isArray(data[i])) {

					item[i] = data[i];

				}else{

					item[i] = [data[i]];

				}

			}

			//Reset the item in the reference.

			self._arrayOfAllItems[item[self._itemNumPropName]] = item;

			//Scan the new values in the item for extra stub items we need to

			//add to the items array of the store so they can be lazy-loaded later...

			var attributes = self.getAttributes(item);

			for(i in attributes){

				var values = self.getValues(item, attributes[i]);

				for (var j = 0; j < values.length; j++) {

					var value = values[j];

					if(typeof value === "object"){

						if(value["stub"] ){

							//We have a stub reference here, we need to create the stub item

							var stub = {

								type: ["stub"],

								name: [value["stub"]],	//

								parent: [itemName]		//The child stub item is parented by this item name...

							};

							if (parent) {

								//Add in any parents to your parent so URL construstruction is accurate.

								stub.parent[0] = parent + "/" + stub.parent[0];

							}

							//Finalize the addition of the new stub item into the ItemFileReadStore list.

							self._arrayOfAllItems.push(stub);

							stub[self._storeRefPropName] = self;

							stub[self._itemNumPropName] = (self._arrayOfAllItems.length - 1); //Last one pushed in should be the item

							values[j] = stub; //Set the stub item back in its place and replace the stub notation.

						}

					}

				}

			}

			//Done processing!  Call the onItem, if any.

			if(keywordArgs.onItem){

				var scope = keywordArgs.scope ? keywordArgs.scope : dojo.global;

				keywordArgs.onItem.call(scope, item);

			}

		};

		//Callback for any errors that occur during load.

		var gotError = function(error){

			//Call the onComplete, if any

			if(keywordArgs.onError){

				var scope = keywordArgs.scope ? keywordArgs.scope : dojo.global;

				keywordArgs.onError.call(scope, error);

			}

		};

		//Fire the get and pass the proper callbacks to the deferred.

		var xhrArgs = {

			url: dataUrl,

			handleAs: "json-comment-optional"

		};

		var d = dojo.xhrGet(xhrArgs);

		d.addCallback(gotData);

		d.addErrback(gotError);

	}

});

}