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Creating Tuple-Serial Entity Bindings
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Creating Tuple-Serial Entity Bindings
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<h2 class="title" style="clear: both"><a id="tuple-serialentitybindings"></a>
Creating Tuple-Serial Entity Bindings
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<p>
In the prior example serial keys and serial values were used,
and the
<a href="../../java/com/sleepycat/bind/serial/SerialSerialBinding.html" target="_top">SerialSerialBinding</a>
base class was used for entity bindings. In this example, tuple
keys and serial values are used and therefore the
<a href="../../java/com/sleepycat/bind/serial/TupleSerialBinding.html" target="_top">TupleSerialBinding</a>
base class is used for entity bindings.
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<p>
As with any entity binding, a key and value is converted to an
entity in the
<a href="../../java/com/sleepycat/bind/serial/TupleSerialBinding.html#entryToObject(com.sleepycat.bind.tuple.TupleInput,%20java.lang.Object)" target="_top">TupleSerialBinding.entryToObject</a>
method, and from an entity to
a key and value in the
<a href="../../java/com/sleepycat/bind/serial/TupleSerialBinding.html#objectToKey(java.lang.Object,%20com.sleepycat.db.DatabaseEntry)" target="_top">TupleSerialBinding.objectToKey</a>
and
<a href="../../java/com/sleepycat/bind/serial/TupleSerialBinding.html#objectToData(java.lang.Object)" target="_top">TupleSerialBinding.objectToData</a>
methods. But since keys are
stored as tuples, not as serialized objects, key fields are read
and written using the
<a href="../../java/com/sleepycat/bind/tuple/TupleInput.html" target="_top">TupleInput</a>
and
<a href="../../java/com/sleepycat/bind/tuple/TupleOutput.html" target="_top">TupleOutput</a>
parameters.
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<p>
The <tt class="classname">SampleViews</tt> class contains the modified entity
binding classes that were defined in the prior example:
<tt class="classname">PartBinding</tt>, <tt class="classname">SupplierBinding</tt> and
<tt class="classname">ShipmentBinding</tt>.
</p>
<a id="tuple_partbinding"></a>
<pre class="programlisting"><b class="userinput"><tt>import com.sleepycat.bind.serial.TupleSerialBinding;
import com.sleepycat.bind.tuple.TupleInput;
import com.sleepycat.bind.tuple.TupleOutput;
...</tt></b>
public class SampleViews
{
...
private static class PartBinding extends <b class="userinput"><tt>TupleSerialBinding</tt></b>
{
private PartBinding(ClassCatalog classCatalog, <b class="userinput"><tt>Class dataClass</tt></b>)
{
super(classCatalog, dataClass);
}
public Object entryToObject(<b class="userinput"><tt>TupleInput</tt></b> keyInput, Object dataInput)
{
<b class="userinput"><tt> String number = keyInput.readString();</tt></b>
PartData data = (PartData) dataInput;
return new Part(<b class="userinput"><tt>number</tt></b>, data.getName(), data.getColor(),
data.getWeight(), data.getCity());
}
public void objectToKey(Object object, TupleOutput output)
{
Part part = (Part) object;
<b class="userinput"><tt> output.writeString(part.getNumber());</tt></b>
}
public Object objectToData(Object object)
{
Part part = (Part) object;
return new PartData(part.getName(), part.getColor(),
part.getWeight(), part.getCity());
}
}
...
private static class SupplierBinding extends <b class="userinput"><tt>TupleSerialBinding</tt></b>
{
private SupplierBinding(ClassCatalog classCatalog, <b class="userinput"><tt>Class dataClass</tt></b>)
{
super(classCatalog, dataClass);
}
public Object entryToObject(<b class="userinput"><tt>TupleInput</tt></b> keyInput, Object dataInput)
{
<b class="userinput"><tt> String number = keyInput.readString();</tt></b>
SupplierData data = (SupplierData) dataInput;
return new Supplier(<b class="userinput"><tt>number</tt></b>, data.getName(),
data.getStatus(), data.getCity());
}
public void objectToKey(Object object, TupleOutput output)
{
Supplier supplier = (Supplier) object;
<b class="userinput"><tt> output.writeString(supplier.getNumber());</tt></b>
}
public Object objectToData(Object object)
{
Supplier supplier = (Supplier) object;
return new SupplierData(supplier.getName(), supplier.getStatus(),
supplier.getCity());
}
}
...
private static class ShipmentBinding extends <b class="userinput"><tt>TupleSerialBinding</tt></b>
{
private ShipmentBinding(ClassCatalog classCatalog, <b class="userinput"><tt>Class dataClass</tt></b>)
{
super(classCatalog, dataClass);
}
public Object entryToObject(<b class="userinput"><tt>TupleInput</tt></b> keyInput, Object dataInput)
{
<b class="userinput"><tt> String partNumber = keyInput.readString();
String supplierNumber = keyInput.readString();</tt></b>
ShipmentData data = (ShipmentData) dataInput;
return new Shipment(<b class="userinput"><tt>partNumber, supplierNumber</tt></b>,
data.getQuantity());
}
public void objectToKey(Object object, TupleOutput output)
{
Shipment shipment = (Shipment) object;
<b class="userinput"><tt> output.writeString(shipment.getPartNumber());
output.writeString(shipment.getSupplierNumber());</tt></b>
}
public Object objectToData(Object object)
{
Shipment shipment = (Shipment) object;
return new ShipmentData(shipment.getQuantity());
}
}
...
} </pre>
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