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* Licensed to the Apache Software Foundation (ASF) under one
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* distributed with this work for additional information
* regarding copyright ownership. The ASF licenses this file
* to you under the Apache License, Version 2.0 (the
* "License"); you may not use this file except in compliance
* with the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
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*/
package arq.examples.riot;
import org.apache.jena.atlas.lib.Sink ;
import org.apache.jena.riot.RDFDataMgr ;
import org.apache.jena.riot.out.SinkTripleOutput ;
import org.apache.jena.riot.system.StreamRDF ;
import org.apache.jena.riot.system.StreamRDFBase ;
import org.apache.jena.riot.system.SyntaxLabels ;
import com.hp.hpl.jena.graph.Node ;
import com.hp.hpl.jena.graph.Triple ;
import com.hp.hpl.jena.rdf.model.Property ;
import com.hp.hpl.jena.sparql.vocabulary.FOAF ;
/** Example of using RIOT : extract only certain properties from a parser run */
public class ExRIOT_4
{
public static void main(String...argv)
{
String filename = "data.ttl" ;
// This is the heart of N-triples printing ... outoput is heavily buffered
// so the FilterSinkRDF called flush at the end of parsing.
Sink<Triple> output = new SinkTripleOutput(System.out, null, SyntaxLabels.createNodeToLabel()) ;
StreamRDF filtered = new FilterSinkRDF(output, FOAF.name, FOAF.knows) ;
// Call the parsing process.
RDFDataMgr.parse(filtered, filename) ;
}
static class FilterSinkRDF extends StreamRDFBase
{
private final Node[] properties ;
// Where to send the filtered triples.
private final Sink<Triple> dest ;
FilterSinkRDF(Sink<Triple> dest, Property... properties)
{
this.dest = dest ;
this.properties = new Node[properties.length] ;
for ( int i = 0 ; i < properties.length ; i++ )
this.properties[i] = properties[i].asNode() ;
}
@Override
public void triple(Triple triple)
{
for ( Node p : properties )
{
if ( triple.getPredicate().equals(p) )
dest.send(triple) ;
}
}
@Override
public void finish()
{
// Output may be buffered.
dest.flush() ;
}
}
}