com.hp.hpl.jena.graph.query
Interface QueryHandler

All Known Implementing Classes:

SimpleQueryHandler

public interface QueryHandler

Method Summary

boolean	containsNode(Node n) true iff the graph contains a triple in which n appears somewhere.
boolean	isEmpty() Answer true iff the graph contains no explicit triples.
ExtendedIterator	objectsFor(Node s, Node p) deliver an iterator over all the objects _o_ such that _(s, p, o)_ is in the underlying graph; nulls count as wildcards.
Stage	patternStage(Mapping map, Graph constraints, Triple[] p) produce a single Stage which will probe the underlying graph for triples matching p and inject all the resulting bindings into the processing stream (see Stage for details) _map_ is the variable binding map to use and update.
BindingQueryPlan	prepareBindings(Query q, Node[] variables) prepare a plan for generating bindings given the query _q_ and the result variables _variables_.
TreeQueryPlan	prepareTree(Graph pattern) deliver a plan for executing the tree-match query defined by _pattern_.
ExtendedIterator	subjectsFor(Node p, Node o) deliver an iterator over all the subjects _s_ such that _(s, p, o)_ is in the underlying graph; nulls count as wildcards.

Method Detail

prepareBindings

public BindingQueryPlan prepareBindings(Query q,
                                        Node[] variables)

prepare a plan for generating bindings given the query _q_ and the result variables _variables_.

patternStage

public Stage patternStage(Mapping map,
                          Graph constraints,
                          Triple[] p)

produce a single Stage which will probe the underlying graph for triples matching p and inject all the resulting bindings into the processing stream (see Stage for details)
_map_ is the variable binding map to use and update. _constraints_ is the current constraint graph: if this Stage can absorb some of the constraints, it may do so, remove them from the graph.

prepareTree

public TreeQueryPlan prepareTree(Graph pattern)

deliver a plan for executing the tree-match query defined by _pattern_.

objectsFor

public ExtendedIterator objectsFor(Node s,
                                   Node p)

deliver an iterator over all the objects _o_ such that _(s, p, o)_ is in the underlying graph; nulls count as wildcards.

subjectsFor

public ExtendedIterator subjectsFor(Node p,
                                    Node o)

deliver an iterator over all the subjects _s_ such that _(s, p, o)_ is in the underlying graph; nulls count as wildcards.

containsNode

public boolean containsNode(Node n)

true iff the graph contains a triple in which n appears somewhere. if n is a fluid node, it is not defined whether true or false is returned, so don't do that.

isEmpty

public boolean isEmpty()

Answer true iff the graph contains no explicit triples.