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Removing the Redundant Value Classes
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<h2 class="title" style="clear: both"><a id="removingredundantvalueclasses"></a>
Removing the Redundant Value Classes
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<p>
The <code class="classname">PartData</code>, <code class="classname">SupplierData</code> and <code class="classname">ShipmentData</code>
classes have been removed in this example, and the <code class="classname">Part</code>,
<code class="classname">Supplier</code> and <code class="classname">Shipment</code> entity classes are used in
their place.
</p>
<p>
The serial formats are created with the entity classes.
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<a id="sentity_sampledatabase"></a>
<pre class="programlisting">public class SampleDatabase
{
...
public SampleDatabase(String homeDirectory)
throws DatabaseException, FileNotFoundException
{
...
secConfig.setKeyCreator(new SupplierByCityKeyCreator(javaCatalog,
<strong class="userinput"><code>Supplier</code></strong>.class));
...
secConfig.setKeyCreator(new ShipmentByPartKeyCreator(javaCatalog,
<strong class="userinput"><code>Shipment</code></strong>.class));
...
secConfig.setKeyCreator(new
ShipmentBySupplierKeyCreator(javaCatalog,
<strong class="userinput"><code>Shipment</code></strong>.class));
...
}
} </pre>
<p>
The index key creator uses the entity class as well.
</p>
<a id="sentity_supplierbycitykeycreator"></a>
<pre class="programlisting">public class SampleDatabase
{
...
private static class SupplierByCityKeyCreator
extends TupleSerialKeyCreator
{
private SupplierByCityKeyCreator(ClassCatalog catalog,
Class valueClass)
{
super(catalog, valueClass);
}
public boolean createSecondaryKey(TupleInput primaryKeyInput,
Object valueInput,
TupleOutput indexKeyOutput)
{
<strong class="userinput"><code>Supplier</code></strong> supplier = (<strong class="userinput"><code>Supplier</code></strong>) valueInput;
String city = supplier.getCity();
if (city != null) {
indexKeyOutput.writeString(supplier.getCity());
return true;
} else {
return false;
}
}
}
} </pre>
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