Interface Quad
- All Superinterfaces:
QuadLike<BlankNodeOrIRI>
,TripleLike
- All Known Subinterfaces:
JsonLdQuad
,RDF4JQuad
- All Known Implementing Classes:
JsonLdQuadImpl
,QuadImpl
,QuadImpl
A Quad
object in Commons RDF is considered
immutable, that is, over its life time it will have
consistent behaviour for its equals(Object)
, and the instances
returned from getGraphName()
, getSubject()
,
getPredicate()
, getObject()
and asTriple()
will
have consistent Object.equals(Object)
behaviour.
Note that Quad
methods are not required to return object
identical (==
) instances as long as they are equivalent
according to Object.equals(Object)
. Specialisations of
Quad
may provide additional methods that are documented to be
mutable.
Quad
methods are thread-safe, however
specialisations may provide additional methods that are documented to not be
thread-safe.
Quad
s can be safely used in hashing collections like
HashSet
and HashMap
.
Any Quad
can be used interchangeably across Commons RDF
implementations.
- Since:
- 0.3.0-incubating
- See Also:
-
Method Summary
Modifier and TypeMethodDescriptiondefault Triple
asTriple()
Adapt this Quad to a Triple.boolean
Check it this Quad is equal to another Quad.The graph name (graph label) of this quad, if present.The predicateIRI
of this quad.The subject of this quad, which may be either aBlankNode
or anIRI
, which are represented in Commons RDF by the interfaceBlankNodeOrIRI
.int
hashCode()
Calculate a hash code for this Quad.
-
Method Details
-
getGraphName
Optional<BlankNodeOrIRI> getGraphName()The graph name (graph label) of this quad, if present. IfOptional.isPresent()
, then theOptional.get()
is either aBlankNode
or anIRI
, indicating the graph name of this Quad. If the graph name is not present, e.g. the value isOptional.empty()
, it indicates that this Quad is in the default graph.- Specified by:
getGraphName
in interfaceQuadLike<BlankNodeOrIRI>
- Returns:
- If
Optional.isPresent()
, the graph nameBlankNodeOrIRI
of this quad, otherwiseOptional.empty()
, indicating the default graph. - See Also:
-
getSubject
BlankNodeOrIRI getSubject()The subject of this quad, which may be either aBlankNode
or anIRI
, which are represented in Commons RDF by the interfaceBlankNodeOrIRI
.- Specified by:
getSubject
in interfaceTripleLike
- Returns:
- The subject
BlankNodeOrIRI
of this quad. - See Also:
-
getPredicate
IRI getPredicate()The predicateIRI
of this quad.- Specified by:
getPredicate
in interfaceTripleLike
- Returns:
- The predicate
IRI
of this quad. - See Also:
-
getObject
RDFTerm getObject()The object of this quad, which may be either aBlankNode
, anIRI
, or aLiteral
, which are represented in Commons RDF by the interfaceRDFTerm
.- Specified by:
getObject
in interfaceTripleLike
- Returns:
- The object
RDFTerm
of this quad. - See Also:
-
asTriple
Adapt this Quad to a Triple.The returned
Triple
will have equivalent values returned from the methodsTripleLike.getSubject()
,TripleLike.getPredicate()
andTripleLike.getObject()
.The returned
Triple
MUST NOT beequals(Object)
to thisQuad
, even if this quad has a default graphgetGraphName()
value ofOptional.empty()
, but MUST follow theTriple.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())); }
Thedefault
implementation of this method return a proxyTriple
instance that keeps a reference to thisQuad
to call the underlyingTripleLike
methods, but supplies aTriple
compatible implementation ofTriple.equals(Object)
andTriple.hashCode()
. Implementations may override this method, e.g. for a more efficient solution.- Returns:
- A
Triple
that contains the sameTripleLike
properties as this Quad.
-
equals
Check it this Quad is equal to another Quad.Two Quads are equal if and only if their
getGraphName()
,getSubject()
,getPredicate()
andgetObject()
are equal.Implementations MUST also override
hashCode()
so that two equal Quads produce the same hash code.Note that a
Quad
MUST NOT be equal to aTriple
, even if this Quad'sgetGraphName()
isOptional.empty()
. To test triple-like equivalence, callers can use:Quad q1; Triple t2; q1.asTriple().equals(t2));
-
hashCode
int hashCode()Calculate a hash code for this Quad.The returned hash code MUST be equal to the result of
Objects.hash(Object...)
with the argumentsgetSubject()
,getPredicate()
,getObject()
,getGraphName()
.This method MUST be implemented in conjunction with
equals(Object)
so that two equalQuad
s produce the same hash code.
-