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Using Transient Fields in an Entity Binding
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Using Transient Fields in an Entity Binding
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Using Transient Fields in an Entity Binding
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<p>
The entity bindings from the prior example have been changed in
this example to use the entity object both as a value object and an
entity object.
</p>
<p>
Before, the <tt class="methodname">entryToObject()</tt> method combined the
deserialized value object with the key fields to create a new
entity object. Now, this method uses the deserialized object
directly as an entity, and initializes its key using the fields
read from the key tuple.
</p>
<p>
Before, the <tt class="methodname">objectToData()</tt> method constructed a new value
object using information in the entity. Now it simply returns the
entity. Nothing needs to be changed in the entity, since the
transient key fields won't be serialized.
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<a id="sentity_partbinding"></a>
<pre class="programlisting">import com.sleepycat.bind.serial.ClassCatalog;
...
public class SampleViews
{
...
private static class PartBinding extends TupleSerialBinding
{
private PartBinding(ClassCatalog classCatalog, Class dataClass)
{
super(classCatalog, dataClass);
}
public Object entryToObject(TupleInput keyInput, Object dataInput)
{
String number = keyInput.readString();
<b class="userinput"><tt> Part part = (Part) dataInput;
part.setKey(number);
return part;</tt></b>
}
public void objectToKey(Object object, TupleOutput output)
{
Part part = (Part) object;
output.writeString(part.getNumber());
}
public Object objectToData(Object object)
{
<b class="userinput"><tt> return object;</tt></b>
}
}
private static class SupplierBinding extends TupleSerialBinding
{
private SupplierBinding(ClassCatalog classCatalog, Class dataClass)
{
super(classCatalog, dataClass);
}
public Object entryToObject(TupleInput keyInput, Object dataInput)
{
String number = keyInput.readString();
<b class="userinput"><tt> Supplier supplier = (Supplier) dataInput;
supplier.setKey(number);
return supplier;</tt></b>
}
public void objectToKey(Object object, TupleOutput output)
{
Supplier supplier = (Supplier) object;
output.writeString(supplier.getNumber());
}
public Object objectToData(Object object)
{
<b class="userinput"><tt> return object;</tt></b>
}
}
private static class ShipmentBinding extends TupleSerialBinding
{
private ShipmentBinding(ClassCatalog classCatalog, Class dataClass)
{
super(classCatalog, dataClass);
}
public Object entryToObject(TupleInput keyInput, Object dataInput)
{
String partNumber = keyInput.readString();
String supplierNumber = keyInput.readString();
<b class="userinput"><tt> Shipment shipment = (Shipment) dataInput;
shipment.setKey(partNumber, supplierNumber);
return shipment;</tt></b>
}
public void objectToKey(Object object, TupleOutput output)
{
Shipment shipment = (Shipment) object;
output.writeString(shipment.getPartNumber());
output.writeString(shipment.getSupplierNumber());
}
public Object objectToData(Object object)
{
<b class="userinput"><tt> return object;</tt></b>
}
}
} </pre>
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