org.apache.jena.mem

Class GraphTripleStoreBase

java.lang.Object

org.apache.jena.mem.GraphTripleStoreBase

All Implemented Interfaces:

TripleStore

Direct Known Subclasses:

GraphTripleStore, GraphTripleStoreMem

public abstract class GraphTripleStoreBase
extends Object
implements TripleStore

Method Summary

Modifier and Type	Method and Description
void	add(Triple t) Add a triple to this triple store.
void	clear() Clear this store, ie remove all triples from it.
void	close() Destroy this triple store - discard the indexes.
boolean	contains(Triple t) Answer true iff this triple store contains the (concrete) triple t.
boolean	containsByEquality(Triple t)
void	delete(Triple t) Remove a triple from this triple store.
ExtendedIterator<Triple>	find(Triple t) Answer an ExtendedIterator returning all the triples from this store that match the pattern m = (S, P, O).
boolean	isEmpty() Answer true iff this triple store is empty.
ExtendedIterator<Node>	listObjects() Answer an setwise iterator over all the objects of triples in this store.
ExtendedIterator<Node>	listPredicates() Answer an iterator over all the predicates of triples in this store.
ExtendedIterator<Node>	listSubjects() Answer an setwise iterator over all the subjects of triples in this store.
int	size() Answer the size (number of triples) of this triple store.

Methods inherited from class java.lang.Object

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

Method Detail

close

public void close()

Destroy this triple store - discard the indexes.

Specified by:

close in interface TripleStore

add

public void add(Triple t)

Add a triple to this triple store.

Specified by:

add in interface TripleStore

delete

public void delete(Triple t)

Remove a triple from this triple store.

Specified by:

delete in interface TripleStore

clear

public void clear()

Clear this store, ie remove all triples from it.

Specified by:

clear in interface TripleStore

size

public int size()

Answer the size (number of triples) of this triple store.

Specified by:

size in interface TripleStore

isEmpty

public boolean isEmpty()

Answer true iff this triple store is empty.

Specified by:

isEmpty in interface TripleStore

listSubjects

public ExtendedIterator<Node> listSubjects()

Description copied from interface: TripleStore

Answer an setwise iterator over all the subjects of triples in this store.

Specified by:

listSubjects in interface TripleStore

listPredicates

public ExtendedIterator<Node> listPredicates()

Description copied from interface: TripleStore

Answer an iterator over all the predicates of triples in this store.

Specified by:

listPredicates in interface TripleStore

listObjects

public ExtendedIterator<Node> listObjects()

Description copied from interface: TripleStore

Answer an setwise iterator over all the objects of triples in this store.

Specified by:

listObjects in interface TripleStore

contains

public boolean contains(Triple t)

Answer true iff this triple store contains the (concrete) triple t.

Specified by:

contains in interface TripleStore

containsByEquality

public boolean containsByEquality(Triple t)

find

public ExtendedIterator<Triple> find(Triple t)

Answer an ExtendedIterator returning all the triples from this store that match the pattern m = (S, P, O).

Because the node-to-triples maps index on each of subject, predicate, and (non-literal) object, concrete S/P/O patterns can immediately select an appropriate map. Because the match for literals must be by sameValueAs, not equality, the optimisation is not applied for literals. [This is probably a Bad Thing for strings.]

Practice suggests doing the predicate test last, because there are "usually" many more statements than predicates, so the predicate doesn't cut down the search space very much. By "practice suggests" I mean that when the order went, accidentally, from S/O/P to S/P/O, performance on (ANY, P, O) searches on largish models with few predicates declined dramatically - specifically on the not-galen.owl ontology.

Specified by:

find in interface TripleStore