Package org.apache.jena.graph

Class GraphUtil

java.lang.Object

org.apache.jena.graph.GraphUtil

public class GraphUtil
extends java.lang.Object

An ad-hoc collection of useful code for graphs

Method Summary

Modifier and Type	Method	Description
static void	add(Graph graph, java.util.Iterator<Triple> it)
static void	add(Graph graph, java.util.List<Triple> triples)
static void	add(Graph graph, Triple[] triples)
static void	addInto(Graph dstGraph, Graph srcGraph)	Add triples into the destination (arg 1) from the source (arg 2)
static boolean	containsNode(Graph graph, Node node)	Does the graph use the node anywhere as a subject, predicate or object?
static void	delete(Graph graph, java.util.Iterator<Triple> it)
static void	delete(Graph graph, java.util.List<Triple> triples)
static void	delete(Graph graph, Triple[] triples)
static void	deleteFrom(Graph dstGraph, Graph srcGraph)	Delete triples in the destination (arg 1) as given in the source (arg 2).
static void	deleteLoopDst(Graph dstGraph, Graph srcGraph)	Delete the triple in srcGraph from dstGraph by checking the contents of dsgGraph against the srcGraph.
static void	deleteLoopSrc(Graph dstGraph, Graph srcGraph)	Delete triples in srcGraph from dstGraph by looping on srcGraph.
static ExtendedIterator<Triple>	findAll(Graph g)	Answer an iterator covering all the triples in the specified graph.
static ExtendedIterator<Node>	listObjects(Graph g, Node s, Node p)	Return an iterator over the unique objects with a given subject and object.
static ExtendedIterator<Node>	listPredicates(Graph g, Node s, Node o)	Return an iterator over the unique predicate between s and o.
static ExtendedIterator<Node>	listSubjects(Graph g, Node p, Node o)	Return an iterator over the unique subjects with predicate p and object o.
static void	remove(Graph g, Node s, Node p, Node o)	A safe and cautious remove() function that converts the remove to a number of Graph.delete(Triple) operations.

Methods inherited from class java.lang.Object

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

Method Detail

listSubjects

public static ExtendedIterator<Node> listSubjects(Graph g,
                                                  Node p,
                                                  Node o)

Return an iterator over the unique subjects with predicate p and object o. p and o can be wildcards (Node.ANY)

Parameters:

g - Graph

p - Predicate - may be Node.ANY

o - Object - may be Node.ANY

Returns:

ExtendedIterator

listPredicates

public static ExtendedIterator<Node> listPredicates(Graph g,
                                                    Node s,
                                                    Node o)

Return an iterator over the unique predicate between s and o. s and o can be wildcards (Node.ANY)

Parameters:

g - Graph

s - Subject - may be Node.ANY

o - Object - may be Node.ANY

Returns:

ExtendedIterator

listObjects

public static ExtendedIterator<Node> listObjects(Graph g,
                                                 Node s,
                                                 Node p)

Return an iterator over the unique objects with a given subject and object. s and p can be wildcards (Node.ANY)

Parameters:

g - Graph

s - Subject - may be Node.ANY

p - Predicate - may be Node.ANY

Returns:

ExtendedIterator

containsNode

public static boolean containsNode(Graph graph,
                                   Node node)

Does the graph use the node anywhere as a subject, predicate or object?

findAll

public static ExtendedIterator<Triple> findAll(Graph g)

Answer an iterator covering all the triples in the specified graph.

Parameters:

g - the graph from which to extract triples

Returns:

an iterator over all the graph's triples

add

public static void add(Graph graph,
                       Triple[] triples)

add

public static void add(Graph graph,
                       java.util.List<Triple> triples)

add

public static void add(Graph graph,
                       java.util.Iterator<Triple> it)

addInto

public static void addInto(Graph dstGraph,
                           Graph srcGraph)

Add triples into the destination (arg 1) from the source (arg 2)

delete

public static void delete(Graph graph,
                          Triple[] triples)

delete

public static void delete(Graph graph,
                          java.util.List<Triple> triples)

delete

public static void delete(Graph graph,
                          java.util.Iterator<Triple> it)

remove

public static void remove(Graph g,
                          Node s,
                          Node p,
                          Node o)

A safe and cautious remove() function that converts the remove to a number of Graph.delete(Triple) operations.

To avoid any possible ConcurrentModificationExceptions, it finds batches of triples, deletes them and tries again until no more triples matching the input can be found.

deleteLoopSrc

public static void deleteLoopSrc(Graph dstGraph,
                                 Graph srcGraph)

Delete triples in srcGraph from dstGraph by looping on srcGraph.

deleteLoopDst

public static void deleteLoopDst(Graph dstGraph,
                                 Graph srcGraph)

Delete the triple in srcGraph from dstGraph by checking the contents of dsgGraph against the srcGraph. This involves calling srcGraph.contains.

Implementation Note:

dstGraph.size() is used by this method.

deleteFrom

public static void deleteFrom(Graph dstGraph,
                              Graph srcGraph)

Delete triples in the destination (arg 1) as given in the source (arg 2).

Implementation Note:

This is designed for the case of dstGraph being comparable or much larger than srcGraph or srcGraph having a lot of triples to actually be deleted from dstGraph. This includes the case of large, persistent dstGraph.

It is not designed for a large srcGraph and large dstGraph with only a few triples in common to delete from dstGraph. It is better to calculate the difference in some way, and copy into a small graph to use as the srcGraph.

To force delete by looping on srcGraph, use deleteLoopSrc(Graph, Graph).

For large srcGraph and small dstGraph, use deleteLoopDst(org.apache.jena.graph.Graph, org.apache.jena.graph.Graph). See discussion on jena/pull/212, (archived at JENA-1284).