com.persistit.ref

Interface PersistitReference

All Superinterfaces:

Serializable

All Known Implementing Classes:

AbstractReference, AbstractWeakReference

public interface PersistitReference
extends Serializable

Interface for reference classes used to isolate object references during serialization.

Any subclass of java.lang.ref.Reference implements this interface; thus applications can use this interface, but implement it using a subclasses of java.lang.ref.WeakReference (for example).

The general problem this interface is intended to solve is to control and reduce the scope of serialization of an object. In a typical application some object A may need to refer to some other object B that has a large graph of connected objects. Using Java's standard serialization mechanism, serializing A also serializes B and all the objects it refers to. This set may be very large, and further, it may be semantically incorrect to serialize the state of B with A because the state of B may change independently of A.

A PersistitReference may be used to break the serialization relationship of B to A. Instead of having a field of A directly containing an instance of B, the field in A would hold a PersistitReference that in turn refers to B. Implementations of PersistitReference are intended to implement it in such a way that only a persistent object identifier for B is stored in the serialized form of the PersistitReference rather than a fully serialization of B. The get method is intended to deserialize (if necessary) and return the object referred to be that persistent identifier. AbstractReference provides such an implementation.

Method Summary

Modifier and Type	Method and Description
Object	get()

Method Detail

get

Object get()

Returns:

The Object this Reference refers to, known as the referent.