Package org.apache.commons.rdf.simple

Class DatasetGraphView

java.lang.Object

org.apache.commons.rdf.simple.DatasetGraphView

All Implemented Interfaces:

java.lang.AutoCloseable, Graph, GraphLike<Triple>

public class DatasetGraphView
extends java.lang.Object
implements Graph

A Graph view on a Dataset.

This view is backed by a Dataset, and can be constructed in two ways:

DatasetGraphView(Dataset)

Expose a union graph view of the Dataset, where all the Quads of the Dataset is represented as a Triple. Adding triples will add them to the default graph, while removing triples will remove from all graphs.

DatasetGraphView(Dataset, BlankNodeOrIRI)

Expose a particular graph of the Dataset, either named by an IRI, a BlankNode, or null for the default graph.

Changes in the Graph are reflected directly in the Dataset and vice versa. This class is thread-safe is the underlying Dataset is thread-safe.

Field Summary

Fields

Modifier and Type	Field	Description
private Dataset	dataset
private BlankNodeOrIRI	namedGraph
private boolean	unionGraph

Constructor Summary

Constructors

Constructor	Description
DatasetGraphView(Dataset dataset)
DatasetGraphView(Dataset dataset, BlankNodeOrIRI namedGraph)

Method Summary

Modifier and Type	Method	Description
void	add(BlankNodeOrIRI subject, IRI predicate, RDFTerm object)	Adds a triple to the graph, possibly mapping any of the components to those supported by this Graph.
void	add(Triple triple)	Adds a triple to the graph, possibly mapping any of the components of the Triple to those supported by this Graph.
void	clear()	Clears the graph, removing all triples.
void	close()	Closes the graph, relinquishing any underlying resources.
boolean	contains(BlankNodeOrIRI subject, IRI predicate, RDFTerm object)	Checks if graph contains a pattern of triples.
boolean	contains(Triple triple)	Checks if graph contains triple.
void	remove(BlankNodeOrIRI subject, IRI predicate, RDFTerm object)	Removes a concrete pattern of triples from the graph.
void	remove(Triple triple)	Removes a concrete triple from the graph.
long	size()	Number of triples contained by the graph.
java.util.stream.Stream<? extends Triple>	stream()	Gets all triples contained by the graph.
java.util.stream.Stream<? extends Triple>	stream(BlankNodeOrIRI subject, IRI predicate, RDFTerm object)	Gets all triples contained by the graph matched with the pattern.
private java.util.Optional<BlankNodeOrIRI>	unionOrNamedGraph()

Methods inherited from class java.lang.Object

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

Methods inherited from interface org.apache.commons.rdf.api.Graph

getTriples, getTriples, iterate, iterate

Field Detail

unionGraph

private final boolean unionGraph

namedGraph

private final BlankNodeOrIRI namedGraph

dataset

private final Dataset dataset

Constructor Detail

DatasetGraphView

public DatasetGraphView(Dataset dataset)

DatasetGraphView

public DatasetGraphView(Dataset dataset,
                        BlankNodeOrIRI namedGraph)

Method Detail

close

public void close()
           throws java.lang.Exception

Description copied from interface: Graph

Closes the graph, relinquishing any underlying resources.

For example, this would close any open file and network streams and free database locks held by the Graph implementation.

The behaviour of the other Graph methods are undefined after closing the graph.

Implementations might not need Graph.close(), hence the default implementation does nothing.

Specified by:

close in interface java.lang.AutoCloseable

Specified by:

close in interface Graph

Throws:

java.lang.Exception

add

public void add(Triple triple)

Description copied from interface: Graph

Adds a triple to the graph, possibly mapping any of the components of the Triple to those supported by this Graph.

Specified by:

add in interface Graph

Specified by:

add in interface GraphLike<Triple>

Parameters:

triple - The triple to add

add

public void add(BlankNodeOrIRI subject,
                IRI predicate,
                RDFTerm object)

Description copied from interface: Graph

Adds a triple to the graph, possibly mapping any of the components to those supported by this Graph.

Specified by:

add in interface Graph

Parameters:

subject - The triple subject

predicate - The triple predicate

object - The triple object

contains

public boolean contains(Triple triple)

Description copied from interface: Graph

Checks if graph contains triple.

Specified by:

contains in interface Graph

Specified by:

contains in interface GraphLike<Triple>

Parameters:

triple - The triple to check.

Returns:

True if the Graph contains the given Triple.

unionOrNamedGraph

private java.util.Optional<BlankNodeOrIRI> unionOrNamedGraph()

contains

public boolean contains(BlankNodeOrIRI subject,
                        IRI predicate,
                        RDFTerm object)

Description copied from interface: Graph

Checks if graph contains a pattern of triples.

Specified by:

contains in interface Graph

Parameters:

subject - The triple subject (null is a wildcard)

predicate - The triple predicate (null is a wildcard)

object - The triple object (null is a wildcard)

Returns:

True if the Graph contains any Triples that match the given pattern.

remove

public void remove(Triple triple)

Description copied from interface: Graph

Removes a concrete triple from the graph.

Specified by:

remove in interface Graph

Specified by:

remove in interface GraphLike<Triple>

Parameters:

triple - triple to remove

remove

public void remove(BlankNodeOrIRI subject,
                   IRI predicate,
                   RDFTerm object)

Description copied from interface: Graph

Removes a concrete pattern of triples from the graph.

Specified by:

remove in interface Graph

Parameters:

subject - The triple subject (null is a wildcard)

predicate - The triple predicate (null is a wildcard)

object - The triple object (null is a wildcard)

clear

public void clear()

Description copied from interface: Graph

Clears the graph, removing all triples.

Specified by:

clear in interface Graph

Specified by:

clear in interface GraphLike<Triple>

size

public long size()

Description copied from interface: Graph

Number of triples contained by the graph.

The count of a set does not include duplicates, consistent with the Triple.equals(Object) equals method for each Triple.

Specified by:

size in interface Graph

Specified by:

size in interface GraphLike<Triple>

Returns:

The number of triples in the graph

stream

public java.util.stream.Stream<? extends Triple> stream()

Description copied from interface: Graph

Gets all triples contained by the graph.

The iteration does not contain any duplicate triples, as determined by the Triple.equals(Object) method for each Triple.

The behaviour of the Stream is not specified if Graph.add(Triple), Graph.remove(Triple) or Graph.clear() are called on the Graph before it terminates.

Implementations may throw ConcurrentModificationException from Stream methods if they detect a conflict while the Stream is active.

Specified by:

stream in interface Graph

Specified by:

stream in interface GraphLike<Triple>

Returns:

A Stream over all of the triples in the graph

stream

public java.util.stream.Stream<? extends Triple> stream(BlankNodeOrIRI subject,
                                                        IRI predicate,
                                                        RDFTerm object)

Description copied from interface: Graph

Gets all triples contained by the graph matched with the pattern.

The iteration does not contain any duplicate triples, as determined by the Triple.equals(Object) method for each Triple.

The behaviour of the Stream is not specified if Graph.add(Triple), Graph.remove(Triple) or Graph.clear() are called on the Graph before it terminates.

Implementations may throw ConcurrentModificationException from Stream methods if they detect a conflict while the Stream is active.

Specified by:

stream in interface Graph

Parameters:

subject - The triple subject (null is a wildcard)

predicate - The triple predicate (null is a wildcard)

object - The triple object (null is a wildcard)

Returns:

A Stream over the matched triples.