org.jrdf.graph.local.iterator
Interface IteratorFactory

All Known Implementing Classes:

DiskIteratorFactory, MemIteratorFactory, OrderedIteratorFactoryImpl

public interface IteratorFactory

Creates the iterators. Allows different implementations of iterators to be used.

Version:

$Id: IteratorFactory.java 1449 2007-09-12 07:15:14Z hamrawee $

Author:

Andrew Newman

Method Summary

ClosableIterator<Triple>	newEmptyClosableIterator() Return an new EmptyClosableIterator - indicates no results found.
ClosableIterator<Triple>	newGraphIterator() Return an new GraphIterator - result of an unconstrained find.
ClosableIterator<Triple>	newOneFixedIterator(Long fixedFirstNode, int index) Return a new FixedIterator - bound by one node.
ClosableIterator<PredicateNode>	newPredicateIterator() Return a new PredicateIterator - all unique predicates.
ClosableIterator<PredicateNode>	newPredicateIterator(Long resource) Return a new PredicateIterator - all unique predicates for a given resource (subject and object).
ClosableIterator<Triple>	newThreeFixedIterator(Long[] nodes) Return a new FixedIterator - bound by three nodes.
ClosableIterator<Triple>	newTwoFixedIterator(Long fixedFirstNode, Long fixedSecondNode, int index) Return a new FixedItereator - bound by two nodes.

Method Detail

newEmptyClosableIterator

ClosableIterator<Triple> newEmptyClosableIterator()

Return an new EmptyClosableIterator - indicates no results found.

Returns:

an empty closable iterator - always hasNext false and next throws exception.

newGraphIterator

ClosableIterator<Triple> newGraphIterator()

Return an new GraphIterator - result of an unconstrained find.

Returns:

a graph iterator - goes through all triples in the graph.

newOneFixedIterator

ClosableIterator<Triple> newOneFixedIterator(Long fixedFirstNode,
                                             int index)

Return a new FixedIterator - bound by one node.

Parameters:

fixedFirstNode - the node to find.

index - which index (from the three) to use.

Returns:

a new FixedIterator - goes through the graph and returns all given triples with the given node.

newTwoFixedIterator

ClosableIterator<Triple> newTwoFixedIterator(Long fixedFirstNode,
                                             Long fixedSecondNode,
                                             int index)

Return a new FixedItereator - bound by two nodes.

Parameters:

fixedFirstNode - the first node to find.

fixedSecondNode - the second node to find.

index - which index (from the three) to use.

Returns:

a new FixedIterator - goes through the graph and returns all given triples with the two given nodes.

newThreeFixedIterator

ClosableIterator<Triple> newThreeFixedIterator(Long[] nodes)

Return a new FixedIterator - bound by three nodes.

Parameters:

nodes - the triple to find.

Returns:

a new FixedIterator - either one or none triples.

newPredicateIterator

ClosableIterator<PredicateNode> newPredicateIterator()

Return a new PredicateIterator - all unique predicates.

Returns:

a new PredicateIterator - all unique predicates.

newPredicateIterator

ClosableIterator<PredicateNode> newPredicateIterator(Long resource)

Return a new PredicateIterator - all unique predicates for a given resource (subject and object).

Parameters:

resource - all unique predicate for a given resource.

Returns:

a new PredicateIterator - all unique predicate for a given resource (subject and object).