org.hypergraphdb.type

Class RecordTypeConstructor

java.lang.Object

org.hypergraphdb.type.HGAtomTypeBase

org.hypergraphdb.type.RecordTypeConstructor

All Implemented Interfaces:

HGGraphHolder, HGAtomType

public class RecordTypeConstructor
extends HGAtomTypeBase

A RecordTypeConstructor represents the HG (meta) type of a RecordType. A RecordType is constituted by a definite set of Slots. It is itself record and managed within hypergraph through a RecordTypeConstructor.

Author:

Borislav Iordanov

Field Summary

Fields inherited from class org.hypergraphdb.type.HGAtomTypeBase

graph

Constructor Summary

Constructors

Constructor and Description
RecordTypeConstructor()

Method Summary

Methods

Modifier and Type	Method and Description
Object	make(HGPersistentHandle handle, LazyRef<HGHandle[]> targetSet, IncidenceSetRef incidenceSet) Construct a new run-time instance of a hypergraph atom.
void	release(HGPersistentHandle handle) Release a hypergraph value instance from the persistent store.
HGPersistentHandle	store(Object instance) Store a run-time instance of a hypergraph atom into the hypergraph HGStore as a new atom.
boolean	subsumes(Object general, Object specific) Return true if the slot set of the general parameter is a subset of the slot set of the specific parameter.

Methods inherited from class org.hypergraphdb.type.HGAtomTypeBase

getHyperGraph, setHyperGraph

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

RecordTypeConstructor

public RecordTypeConstructor()

Method Detail

make

public Object make(HGPersistentHandle handle,
          LazyRef<HGHandle[]> targetSet,
          IncidenceSetRef incidenceSet)

Description copied from interface: HGAtomType

Construct a new run-time instance of a hypergraph atom. A plain node must be constructed whenever the targetSet parameter is null or of length 0. Otherwise, a HGLink instance must be constructed.

It is not required that all atom types be able to construct both plain (node) atoms and HGLinks. It is up to an HGAtomType implementation to support either or both. When a HGLink counterpart is not available for a particular run-time type, an implementation may choose to create an instance of the default link value holder implementation HGValuedLink, provided by HyperGraph.

Parameters:

handle - The HGPersistentHandle of the atom value.

targetSet - When the atom is a link, this parameter holds the target set of the link. When the atom is a node, the parameter is an array of 0 length.

incidenceSet - A lazy reference to the set of links pointing to this atom. This is null if we are constructing an internal/nested value of some complex type.

Returns:

The run-time atom instance. The return value should never be null. In case the handle points to an invalid instance (inexisting or with a erronous layout), the method should throw a HGException.

store

public HGPersistentHandle store(Object instance)

Description copied from interface: HGAtomType

Store a run-time instance of a hypergraph atom into the hypergraph HGStore as a new atom.

Parameters:

instance - The atom instance.

Returns:

The persistent handle of the stored value.

release

public void release(HGPersistentHandle handle)

Description copied from interface: HGAtomType

Release a hypergraph value instance from the persistent store.

This method should be called when a HGPersistentHandle returned from the store is no longer in use.

Parameters:

handle - The persistent handle of the value to release.

subsumes

public boolean subsumes(Object general,
               Object specific)

Return true if the slot set of the general parameter is a subset of the slot set of the specific parameter.

Specified by:

subsumes in interface HGAtomType

Overrides:

subsumes in class HGAtomTypeBase

Parameters:

general - The object which might be more general. Cannot be null.

specific - The object which might be more specific. Cannot be null.

Returns:

true if specific can be used whenever general is required and false otherwise.