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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 class="ulink" 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 class="ulink" href="../../java/com/sleepycat/bind/serial/TupleSerialBinding.html" target="_top">TupleSerialBinding</a>
base class is used for entity bindings.
</p>
<p>
As with any entity binding, a key and value is converted to an
entity in the
<a class="ulink" 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 class="ulink" href="../../java/com/sleepycat/bind/serial/TupleSerialBinding.html#objectToKey(java.lang.Object,%20com.sleepycat.db.DatabaseEntry)" target="_top">TupleSerialBinding.objectToKey</a>
and
<a class="ulink" 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 class="ulink" href="../../java/com/sleepycat/bind/tuple/TupleInput.html" target="_top">TupleInput</a>
and
<a class="ulink" href="../../java/com/sleepycat/bind/tuple/TupleOutput.html" target="_top">TupleOutput</a>
parameters.
</p>
<p>
The <code class="classname">SampleViews</code> class contains the modified entity
binding classes that were defined in the prior example:
<code class="classname">PartBinding</code>, <code class="classname">SupplierBinding</code> and
<code class="classname">ShipmentBinding</code>.
</p>
<a id="tuple_partbinding"></a>
<pre class="programlisting"><strong class="userinput"><code>import com.sleepycat.bind.serial.TupleSerialBinding;
import com.sleepycat.bind.tuple.TupleInput;
import com.sleepycat.bind.tuple.TupleOutput;
...</code></strong>
public class SampleViews
{
...
private static class PartBinding extends <strong class="userinput"><code>TupleSerialBinding</code></strong>
{
private PartBinding(ClassCatalog classCatalog, <strong class="userinput"><code>Class dataClass</code></strong>)
{
super(classCatalog, dataClass);
}
public Object entryToObject(<strong class="userinput"><code>TupleInput</code></strong> keyInput, Object dataInput)
{
<strong class="userinput"><code> String number = keyInput.readString();</code></strong>
PartData data = (PartData) dataInput;
return new Part(<strong class="userinput"><code>number</code></strong>, data.getName(), data.getColor(),
data.getWeight(), data.getCity());
}
public void objectToKey(Object object, TupleOutput output)
{
Part part = (Part) object;
<strong class="userinput"><code> output.writeString(part.getNumber());</code></strong>
}
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 <strong class="userinput"><code>TupleSerialBinding</code></strong>
{
private SupplierBinding(ClassCatalog classCatalog, <strong class="userinput"><code>Class dataClass</code></strong>)
{
super(classCatalog, dataClass);
}
public Object entryToObject(<strong class="userinput"><code>TupleInput</code></strong> keyInput, Object dataInput)
{
<strong class="userinput"><code> String number = keyInput.readString();</code></strong>
SupplierData data = (SupplierData) dataInput;
return new Supplier(<strong class="userinput"><code>number</code></strong>, data.getName(),
data.getStatus(), data.getCity());
}
public void objectToKey(Object object, TupleOutput output)
{
Supplier supplier = (Supplier) object;
<strong class="userinput"><code> output.writeString(supplier.getNumber());</code></strong>
}
public Object objectToData(Object object)
{
Supplier supplier = (Supplier) object;
return new SupplierData(supplier.getName(),
supplier.getStatus(),
supplier.getCity());
}
}
...
private static class ShipmentBinding extends <strong class="userinput"><code>TupleSerialBinding</code></strong>
{
private ShipmentBinding(ClassCatalog classCatalog, <strong class="userinput"><code>Class dataClass</code></strong>)
{
super(classCatalog, dataClass);
}
public Object entryToObject(<strong class="userinput"><code>TupleInput</code></strong> keyInput, Object dataInput)
{
<strong class="userinput"><code> String partNumber = keyInput.readString();
String supplierNumber = keyInput.readString();</code></strong>
ShipmentData data = (ShipmentData) dataInput;
return new Shipment(<strong class="userinput"><code>partNumber, supplierNumber</code></strong>,
data.getQuantity());
}
public void objectToKey(Object object, TupleOutput output)
{
Shipment shipment = (Shipment) object;
<strong class="userinput"><code> output.writeString(shipment.getPartNumber());
output.writeString(shipment.getSupplierNumber());</code></strong>
}
public Object objectToData(Object object)
{
Shipment shipment = (Shipment) object;
return new ShipmentData(shipment.getQuantity());
}
}
...
} </pre>
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