Package org.wikidata.wdtk.rdf

Class SnakRdfConverter

java.lang.Object

org.wikidata.wdtk.rdf.SnakRdfConverter

All Implemented Interfaces:

SnakVisitor<Void>

public class SnakRdfConverter
extends Object
implements SnakVisitor<Void>

Class to convert Wikibase snaks to RDF. The main entry point for this class is writeSnak(Snak, Resource, PropertyContext). Alternatively, one can use setSnakContext(Resource, PropertyContext) and use the class as a visitor. SomeValueSnak and NoValueSnak require further RDF triples to be written; the same is true for some complex data values that might be used with ValueSnak. In such cases, the class stores the values to a buffer. Methods for writing additional triples for these buffered values can be called later.

Author:

Markus Kroetzsch

Constructor Summary

Constructors

Constructor	Description
SnakRdfConverter(RdfWriter rdfWriter, OwlDeclarationBuffer owlDeclarationBuffer, PropertyRegister propertyRegister, AnyValueConverter valueRdfConverter)

Method Summary

Modifier and Type	Method	Description
void	setSnakContext(org.eclipse.rdf4j.model.Resource subject, PropertyContext propertyContext)	Sets the context in which snaks should be used.
Void	visit(NoValueSnak snak)	Visits a NoValueSnak and returns a result.
Void	visit(SomeValueSnak snak)	Visits a SomeValueSnak and returns a result.
Void	visit(ValueSnak snak)	Visits a ValueSnak and returns a result.
void	writeAuxiliaryTriples()	Writes all auxiliary triples that have been buffered recently.
void	writeSnak(Snak snak, org.eclipse.rdf4j.model.Resource subject, PropertyContext propertyContext)	Writes the given snak for the given subject.

Methods inherited from class java.lang.Object

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

Constructor Details

SnakRdfConverter

public SnakRdfConverter(RdfWriter rdfWriter,
 OwlDeclarationBuffer owlDeclarationBuffer,
 PropertyRegister propertyRegister,
 AnyValueConverter valueRdfConverter)

Method Details

writeSnak

public void writeSnak(Snak snak,
 org.eclipse.rdf4j.model.Resource subject,
 PropertyContext propertyContext)

Writes the given snak for the given subject. The context defines if the snak is used as a main snak, qualifier, or in a reference. Some data might be buffered instead of being written immediately. The method writeAuxiliaryTriples() needs to be called to serialize this additional data later on.

Parameters:

snak - the snake to write

subject - the resource that should be used as a subject of the serialied triples

propertyContext - the context in which the snak is used

setSnakContext

public void setSnakContext(org.eclipse.rdf4j.model.Resource subject,
 PropertyContext propertyContext)

Sets the context in which snaks should be used. This is useful when converting many snaks that have the same context. In this case, one can set the context manually and use the converter as a SnakVisitor.

Parameters:

subject - the resource that should be used as a subject of the serialied triples

propertyContext - the context in which the snaks that are to be converted are used

visit

public Void visit(ValueSnak snak)

Description copied from interface: SnakVisitor

Visits a ValueSnak and returns a result.

Specified by:

visit in interface SnakVisitor<Void>

Parameters:

snak - the snak to visit

Returns:

the result for this snak

visit

public Void visit(SomeValueSnak snak)

Description copied from interface: SnakVisitor

Visits a SomeValueSnak and returns a result.

Specified by:

visit in interface SnakVisitor<Void>

Parameters:

snak - the snak to visit

Returns:

the result for this snak

visit

public Void visit(NoValueSnak snak)

Description copied from interface: SnakVisitor

Visits a NoValueSnak and returns a result.

Specified by:

visit in interface SnakVisitor<Void>

Parameters:

snak - the snak to visit

Returns:

the result for this snak

writeAuxiliaryTriples

public void writeAuxiliaryTriples()
                           throws org.eclipse.rdf4j.rio.RDFHandlerException

Writes all auxiliary triples that have been buffered recently. This includes OWL property restrictions but it also includes any auxiliary triples required by complex values that were used in snaks.

Throws:

org.eclipse.rdf4j.rio.RDFHandlerException - if there was a problem writing the RDF triples