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<!-- |
This file is a simple loader for the Lazy Load demo of a Datastore. In this |
Example, a simple extension of ItemFileReadStore that can do rudimentary lazy-loading |
of items into the store is used to showcase how Datastores can hide how data |
is loaded from the widget. As long as the widget implements to the Dojo.data API |
spec, then it should be able to use most datastores as input sources for its |
values. |
--> |
<html> |
<head> |
<title>Demo of Lazy Loading Datastore</title> |
<style type="text/css"> |
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@import "../../../dijit/themes/tundra/tundra.css"; |
@import "../../../dojo/resources/dojo.css"; |
@import "../../../dijit/tests/css/dijitTests.css"; |
</style> |
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<script type="text/javascript" src="../../../dojo/dojo.js" djConfig="isDebug: true, parseOnLoad: true, usePlainJson: true"></script> |
<script type="text/javascript"> |
dojo.require("dojo.parser"); |
dojo.require("dojox.data.demos.stores.LazyLoadJSIStore"); |
dojo.require("dijit.Tree"); |
</script> |
</head> |
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<body class="tundra"> |
<h1> |
DEMO: Lazy Loading Datastore used by dijit.Tree |
</h1> |
<hr> |
<h3> |
Description: |
</h3> |
<p> |
This simple demo shows how the dijit.Tree widget can work with a Datastore that does lazy-loading of values into the tree. |
In this demo, the Datastore is an extension of ItemFileReadStore that overrides the <i>isItemLoaded()</i> and <i>loadItem()</i> functions of |
with ones that can detect 'stub' items and use the data in the stub item to load the real data for that item when it |
is required. In this demo, the real data is required when one of the tree nodes is expanded. |
</p> |
<p> |
The key thing to note is that all the lazy-loading logic (how to locate the data from the backend and so forth) is encapsulated |
into the store functions. The dijit.Tree widget only knows about and uses the dojo.data.Read API interfaces to call to the store to |
get items, test if child items are fully loaded or not, and to invoke the <i>loadItem()</i> function on items that are not yet fully |
loaded but have been requested to be expanded into view. It has no knowledge of how the store actually goes and gets the data. |
</p> |
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<blockquote> |
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<!-- |
The store instance used by this demo. |
--> |
<div dojoType="dojox.data.demos.stores.LazyLoadJSIStore" jsId="continentStore" |
url="geography/root.json"></div> |
|
<!-- |
Display the toplevel tree with items that have an attribute of 'type', |
with value of 'contintent' |
--> |
<b>Continents</b> |
<div dojoType="dijit.Tree" id=tree label="Continents" store="continentStore" query="{type:'continent'}" |
labelAttr="name" typeAttr="type"></div> |
</blockquote> |
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</body> |
</html> |