| New file |
|---|
| 0,0 → 1,142 |
|---|
| 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); |
| } |
| }); |
| |
| |
| } |