Serial bindings were used in prior examples as key bindings, and
	keys were stored as serialized objects. In this example, a tuple
	binding is used for each key since keys will be stored as tuples.
	Because keys are no longer stored as serialized objects, the
	PartKey, SupplierKey and ShipmentKey classes
	no longer implement the 
    Serializable
    
	interface (this is the only change to these classes and is not
	shown below).
    For the Part key, Supplier key, 
    and Shipment key, the
	SampleViews class was changed in this example to create a
	custom 
    TupleBinding
    
	instead of a 
    SerialBinding.
	The custom tuple key binding classes are defined further below.
import com.sleepycat.bind.tuple.TupleBinding; ...public class SampleViews { ... public SampleViews(SampleDatabase db) { ... ClassCatalog catalog = db.getClassCatalog();EntryBinding partKeyBinding = new PartKeyBinding(); EntityBinding partDataBinding = new PartBinding(catalog, PartData.class); EntryBinding supplierKeyBinding = new SupplierKeyBinding(); EntityBinding supplierDataBinding = new SupplierBinding(catalog, SupplierData.class); EntryBinding shipmentKeyBinding = new ShipmentKeyBinding(); EntityBinding shipmentDataBinding = new ShipmentBinding(catalog, ShipmentData.class); EntryBinding cityKeyBinding = TupleBinding.getPrimitiveBinding(String.class);... } }
For the City key, however, a custom binding class is not needed because the key class is a primitive Java type, String. For any primitive Java type, a tuple binding may be created using the TupleBinding.getPrimitiveBinding static method.
    The custom key binding classes, PartKeyBinding,
	SupplierKeyBinding and ShipmentKeyBinding, are
	defined by extending the 
    TupleBinding
    
	class. The 
    TupleBinding
    
	abstract class implements the 
    EntryBinding
    
	interface, and is used for one-to-one bindings between tuples and
	objects. Each binding class implements two methods for converting
	between tuples and objects. Tuple fields are read using the
	TupleInput
	
	parameter and written using the 
    TupleOutput
    
	parameter.
import com.sleepycat.bind.tuple.TupleBinding; import com.sleepycat.bind.tuple.TupleInput; import com.sleepycat.bind.tuple.TupleOutput; ...public class SampleViews { ...private static class PartKeyBinding extends TupleBinding { private PartKeyBinding() { } public Object entryToObject(TupleInput input) { String number = input.readString(); return new PartKey(number); } public void objectToEntry(Object object, TupleOutput output) { PartKey key = (PartKey) object; output.writeString(key.getNumber()); } } ... private static class SupplierKeyBinding extends TupleBinding { private SupplierKeyBinding() { } public Object entryToObject(TupleInput input) { String number = input.readString(); return new SupplierKey(number); } public void objectToEntry(Object object, TupleOutput output) { SupplierKey key = (SupplierKey) object; output.writeString(key.getNumber()); } } ... private static class ShipmentKeyBinding extends TupleBinding { private ShipmentKeyBinding() { } public Object entryToObject(TupleInput input) { String partNumber = input.readString(); String supplierNumber = input.readString(); return new ShipmentKey(partNumber, supplierNumber); } public void objectToEntry(Object object, TupleOutput output) { ShipmentKey key = (ShipmentKey) object; output.writeString(key.getPartNumber()); output.writeString(key.getSupplierNumber()); } }... }