67 lines
2.6 KiB
HTML
67 lines
2.6 KiB
HTML
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<!--
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This file is a simple loader for the Lazy Load demo of a Datastore. In this
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Example, a simple extension of ItemFileReadStore that can do rudimentary lazy-loading
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of items into the store is used to showcase how Datastores can hide how data
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is loaded from the widget. As long as the widget implements to the Dojo.data API
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spec, then it should be able to use most datastores as input sources for its
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values.
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-->
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<html>
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<head>
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<title>Demo of Lazy Loading Datastore</title>
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<style type="text/css">
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@import "../../../dijit/themes/tundra/tundra.css";
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@import "../../../dojo/resources/dojo.css";
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@import "../../../dijit/tests/css/dijitTests.css";
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</style>
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<script type="text/javascript" src="../../../dojo/dojo.js" djConfig="isDebug: true, parseOnLoad: true, usePlainJson: true"></script>
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<script type="text/javascript">
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dojo.require("dojo.parser");
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dojo.require("dojox.data.demos.stores.LazyLoadJSIStore");
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dojo.require("dijit.Tree");
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</script>
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</head>
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<body class="tundra">
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<h1>
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DEMO: Lazy Loading Datastore used by dijit.Tree
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</h1>
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<hr>
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<h3>
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Description:
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</h3>
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<p>
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This simple demo shows how the dijit.Tree widget can work with a Datastore that does lazy-loading of values into the tree.
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In this demo, the Datastore is an extension of ItemFileReadStore that overrides the <i>isItemLoaded()</i> and <i>loadItem()</i> functions of
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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
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is required. In this demo, the real data is required when one of the tree nodes is expanded.
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</p>
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<p>
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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
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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
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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
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loaded but have been requested to be expanded into view. It has no knowledge of how the store actually goes and gets the data.
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</p>
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<blockquote>
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<!--
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The store instance used by this demo.
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-->
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<div dojoType="dojox.data.demos.stores.LazyLoadJSIStore" jsId="continentStore"
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url="geography/root.json"></div>
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<!--
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Display the toplevel tree with items that have an attribute of 'type',
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with value of 'contintent'
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-->
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<b>Continents</b>
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<div dojoType="dijit.Tree" id=tree label="Continents" store="continentStore" query="{type:'continent'}"
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labelAttr="name" typeAttr="type"></div>
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</blockquote>
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</body>
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</html>
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