dijit.Tree violates the dojo.data API.

[Jared Jurkiewicz]

The dijit.Tree widget is violating the dojo.data API and is failing with some stores because of it. This can easily be seen in the demo example:

dojox/data/demos/demo_MultiStores.html

dijit._tree.Controller, on line 28:

if the store supports Notification, subscribe to the notifcation events if (this.store._featuresdojo.data.api.Notification?){

dojo.connect(this.store, "onNew", this, "onNew"); dojo.connect(this.store, "onDelete", this, "onDelete"); dojo.connect(this.store, "onSet", this, "onSet");

}

The widget is accessing internal properties. _features is not an exposed property of the dojo.data API and access in this manner is invalid (and does break). The propery way to access the featureset a store implements is via the getFeatures() function, as defined in: dojo.data.api.Read, and in documentation:

​http://www.dojotoolkit.org/book/dojo-book-0-9/part-3-programmatic-dijit-and-dojo/what-dojo-data/dojo-data-design/read-api

[Jared Jurkiewicz]

The more proper manner to be looking up features is:

if the store supports Notification, subscribe to the notifcation events if (this.store.getFeatures()dojo.data.api.Notification?){

dojo.connect(this.store, "onNew", this, "onNew"); dojo.connect(this.store, "onDelete", this, "onDelete"); dojo.connect(this.store, "onSet", this, "onSet");

}

And there are other problems still. It assumes that all stores implement the Identity API, which is not true.

The code which does the binding should be checking to see if that feature is supported as well.

Basically, because of the dojo.data API violations, the only store Tree is going to work with is ItemFileReadStore?. None of the dojox.data stores work anymore and this breaks almost all the demos in dojox/data/demos as well that showed using datastores with widgets. :-(

[Jared Jurkiewicz]

Well, it at least breaks the MultiStore? widgets one, where I demonstrated using different data stores with Tree and ComboBox? and how that they 'just worked'.

[Jared Jurkiewicz]

Patch for _tree/Controller.js for problem with getFeatures API

[Jared Jurkiewicz]

(In [10316]) Fixing problem with internal property access. refs #4238

[bill]

The remaining issue is with getIdentity(), but it's not a bug per se. Tree just requires a store that implements getIdentity(). Might be able to avoid that requirement for read only trees but at this point I don't see a reason to complicate the tree code in that way.