/**
* Licensed to the Apache Software Foundation (ASF) under one
* or more contributor license agreements. See the NOTICE file
* 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,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package org.apache.jena.riot.writer;
import java.io.BufferedWriter ;
import java.io.OutputStream ;
import java.io.Writer ;
import org.apache.jena.atlas.io.IndentedWriter ;
import org.apache.jena.riot.out.NodeFormatterTTL ;
import org.apache.jena.riot.out.NodeToLabel ;
import org.apache.jena.riot.system.PrefixMap ;
import org.apache.jena.riot.system.PrefixMapFactory ;
import org.apache.jena.riot.system.RiotLib ;
import org.apache.jena.riot.system.StreamRDF ;
import com.hp.hpl.jena.graph.Node ;
import com.hp.hpl.jena.graph.Triple ;
import com.hp.hpl.jena.sparql.core.Quad ;
/** Core engine for output of triples / quads that is streaming.
* Handles prefixes and base, toegtehr with the environment for processing.
* If fed only quads, the output is valid TriG.
* If fed only triples, the output is valid Turtle.
*/
public abstract class WriterStreamRDFBase implements StreamRDF
{
// What did we do last?
protected boolean activeTripleData = false ;
protected boolean activeQuadData = false ;
protected boolean lastWasDirective = false ;
protected final PrefixMap pMap ;
protected String baseURI = null ;
protected final NodeToLabel nodeToLabel ;
protected NodeFormatterTTL fmt ;
protected final IndentedWriter out ;
public WriterStreamRDFBase(OutputStream output)
{
this(new IndentedWriter(output)) ;
}
public WriterStreamRDFBase(IndentedWriter output)
{
out = output ;
baseURI = null ;
pMap = PrefixMapFactory.create() ;
nodeToLabel = NodeToLabel.createScopeByDocument() ;
setFormatter() ;
}
private void setFormatter()
{
fmt = new NodeFormatterTTL(baseURI, pMap, nodeToLabel) ;
}
public WriterStreamRDFBase(Writer output)
{ this(wrap(output)) ; }
private static IndentedWriter wrap(Writer output)
{
if ( ! ( output instanceof BufferedWriter ) )
output = new BufferedWriter(output, 32*1024) ;
return RiotLib.create(output) ;
}
private void reset$()
{
activeTripleData = false ;
activeQuadData = false ;
lastWasDirective = false ;
}
@Override
public final void start()
{
reset$() ;
startData() ;
}
@Override
public final void finish()
{
endData() ;
out.flush() ;
}
@Override
public final void triple(Triple triple)
{
print(triple) ;
activeTripleData = true ;
}
@Override
public final void quad(Quad quad)
{
print(quad) ;
activeQuadData = true ;
}
@Override
public final void base(String base)
{
baseURI = base ;
setFormatter() ;
}
@Override
public final void prefix(String prefix, String iri)
{
endData() ;
lastWasDirective = true ;
out.print("@prefix ") ;
out.print(prefix) ;
out.print(": <") ;
out.print(iri) ; // Don't let it be abbreviated!
out.println("> .") ;
pMap.add(prefix, iri) ;
}
protected void outputNode(Node n)
{
fmt.format(out, n) ;
}
// Subclass contract
protected abstract void startData() ;
protected abstract void endData() ;
protected abstract void print(Quad quad) ;
protected abstract void print(Triple triple) ;
protected abstract void reset() ;
protected void DEBUG(String fmt, Object...args)
{
int loc = out.getCol() ; // Absolute
int off = out.getAbsoluteIndent() ;
out.ensureStartOfLine();
out.setAbsoluteIndent(0) ;
out.println(String.format(fmt, args)) ;
out.setAbsoluteIndent(off) ;
out.ensureStartOfLine();
out.pad(loc, true) ;
}
}