Class QuadImpl

java.lang.Object

org.apache.commons.rdf.simple.QuadImpl

All Implemented Interfaces:

Quad, QuadLike<BlankNodeOrIRI>, TripleLike

final class QuadImpl
extends Object
implements Quad

A simple implementation of Quad.

Field Summary

Fields

Modifier and Type	Field	Description
private final BlankNodeOrIRI	graphName
private final RDFTerm	object
private final IRI	predicate
private final BlankNodeOrIRI	subject

Constructor Summary

Constructors

Constructor	Description
QuadImpl(BlankNodeOrIRI graphName, BlankNodeOrIRI subject, IRI predicate, RDFTerm object)	Construct Quad from its constituent parts.

Method Summary

Modifier and Type	Method	Description
Triple	asTriple()	Adapt this Quad to a Triple.
boolean	equals(Object obj)	Check it this Quad is equal to another Quad.
Optional<BlankNodeOrIRI>	getGraphName()	The graph name (graph label) of this quad, if present.
RDFTerm	getObject()	The object of this quad, which may be either a BlankNode, an IRI, or a Literal, which are represented in Commons RDF by the interface RDFTerm.
IRI	getPredicate()	The predicate IRI of this quad.
BlankNodeOrIRI	getSubject()	The subject of this quad, which may be either a BlankNode or an IRI, which are represented in Commons RDF by the interface BlankNodeOrIRI.
int	hashCode()	Calculate a hash code for this Quad.
String	toString()

Methods inherited from class Object

clone, finalize, getClass, notify, notifyAll, wait, wait, wait

Field Details

graphName

private final BlankNodeOrIRI graphName

subject

private final BlankNodeOrIRI subject

predicate

private final IRI predicate

object

private final RDFTerm object

Constructor Details

QuadImpl

public QuadImpl(BlankNodeOrIRI graphName,
 BlankNodeOrIRI subject,
 IRI predicate,
 RDFTerm object)

Construct Quad from its constituent parts.

The objects are not changed. All mapping of BNode objects is done in SimpleRDF.createQuad(BlankNodeOrIRI, BlankNodeOrIRI, IRI, RDFTerm).

Parameters:

graphName - graphName of triple

subject - subject of triple

predicate - predicate of triple

object - object of triple

Method Details

getGraphName

public Optional<BlankNodeOrIRI> getGraphName()

Description copied from interface: Quad

The graph name (graph label) of this quad, if present. If Optional.isPresent(), then the Optional.get() is either a BlankNode or an IRI, indicating the graph name of this Quad. If the graph name is not present, e.g. the value is Optional.empty(), it indicates that this Quad is in the default graph.

Specified by:

getGraphName in interface Quad

Specified by:

getGraphName in interface QuadLike<BlankNodeOrIRI>

Returns:

If Optional.isPresent(), the graph name BlankNodeOrIRI of this quad, otherwise Optional.empty(), indicating the default graph.

See Also:

• RDF- 1.1 Dataset

getSubject

public BlankNodeOrIRI getSubject()

Description copied from interface: Quad

The subject of this quad, which may be either a BlankNode or an IRI, which are represented in Commons RDF by the interface BlankNodeOrIRI.

Specified by:

getSubject in interface Quad

Specified by:

getSubject in interface TripleLike

Returns:

The subject BlankNodeOrIRI of this quad.

See Also:

• RDF-1.1 Triple subject

getPredicate

public IRI getPredicate()

Description copied from interface: Quad

The predicate IRI of this quad.

Specified by:

getPredicate in interface Quad

Specified by:

getPredicate in interface TripleLike

Returns:

The predicate IRI of this quad.

See Also:

• RDF-1.1 Triple predicate

getObject

public RDFTerm getObject()

Description copied from interface: Quad

The object of this quad, which may be either a BlankNode, an IRI, or a Literal, which are represented in Commons RDF by the interface RDFTerm.

Specified by:

getObject in interface Quad

Specified by:

getObject in interface TripleLike

Returns:

The object RDFTerm of this quad.

See Also:

• RDF-1.1 Triple object

toString

public String toString()

Overrides:

toString in class Object

hashCode

public int hashCode()

Description copied from interface: Quad

Calculate a hash code for this Quad.

The returned hash code MUST be equal to the result of Objects.hash(Object...) with the arguments Quad.getSubject(), Quad.getPredicate(), Quad.getObject(), Quad.getGraphName().

This method MUST be implemented in conjunction with Quad.equals(Object) so that two equal Quads produce the same hash code.

Specified by:

hashCode in interface Quad

Overrides:

hashCode in class Object

Returns:

a hash code value for this Quad.

See Also:

• Object.hashCode()
• Objects.hash(Object...)

equals

public boolean equals(Object obj)

Description copied from interface: Quad

Check it this Quad is equal to another Quad.

Two Quads are equal if and only if their Quad.getGraphName(), Quad.getSubject(), Quad.getPredicate() and Quad.getObject() are equal.

Implementations MUST also override Quad.hashCode() so that two equal Quads produce the same hash code.

Note that a Quad MUST NOT be equal to a Triple, even if this Quad's Quad.getGraphName() is Optional.empty(). To test triple-like equivalence, callers can use:

Quad q1;
Triple t2;
q1.asTriple().equals(t2));

Specified by:

equals in interface Quad

Overrides:

equals in class Object

Parameters:

obj - Another object

Returns:

true if other is a Quad and is equal to this

See Also:

• Object.equals(Object)

asTriple

public Triple asTriple()

Description copied from interface: Quad

Adapt this Quad to a Triple.

The returned Triple will have equivalent values returned from the methods TripleLike.getSubject(), TripleLike.getPredicate() and TripleLike.getObject().

The returned Triple MUST NOT be Quad.equals(Object) to this Quad, even if this quad has a default graph Quad.getGraphName() value of Optional.empty(), but MUST follow the Triple.equals(Object) semantics. This means that the following MUST be true:

Quad q1, q2;
if (q1.equals(q2)) {
    assert (q1.asTriple().equals(q2.asTriple()));
} else if (q1.asTriple().equals(q2.asTriple())) {
    assert (q1.getSubject().equals(q2.getSubject()));
    assert (q1.getPredicate().equals(q2.getPredicate()));
    assert (q1.getObject().equals(q2.getObject()));
    assert (!q1.getGraphName().equals(q2.getGraphName()));
}

The default implementation of this method return a proxy Triple instance that keeps a reference to this Quad to call the underlying TripleLike methods, but supplies a Triple compatible implementation of Triple.equals(Object) and Triple.hashCode(). Implementations may override this method, e.g. for a more efficient solution.

Specified by:

asTriple in interface Quad

Returns:

A Triple that contains the same TripleLike properties as this Quad.