/*
* 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 com.hp.hpl.jena.sparql.engine.binding;
import java.io.IOException ;
import java.io.OutputStream ;
import java.io.Writer ;
import java.util.List ;
import java.util.Map ;
import org.apache.jena.atlas.io.IO ;
import org.apache.jena.atlas.io.AWriter ;
import org.apache.jena.atlas.iterator.Iter ;
import org.apache.jena.atlas.lib.Sink ;
import org.apache.jena.iri.IRI ;
import org.apache.jena.riot.RiotException ;
import org.apache.jena.riot.out.NodeFormatter ;
import org.apache.jena.riot.out.NodeFormatterTTL ;
import org.apache.jena.riot.system.PrefixMap ;
import com.hp.hpl.jena.graph.Node ;
import com.hp.hpl.jena.sparql.core.Var ;
/** Parser for the RDF Tuples language */
public class BindingOutputStream implements Sink<Binding>
{
private final AWriter bw ;
private Binding lastBinding = null ;
private List<Var> vars = null ;
private PrefixMap pmap ;
private NodeFormatter nodeFormatter ;
private boolean needOutputPMap = true ;
private boolean needOutputVars = true ;
public BindingOutputStream(OutputStream out)
{
this(out, null, null) ;
}
public BindingOutputStream(OutputStream out, PrefixMap prefixMapping)
{
this(out, null, prefixMapping) ;
}
public BindingOutputStream(OutputStream out, List<Var> vars)
{
this(out, vars, null) ;
}
public BindingOutputStream(OutputStream out, List<Var> vars, PrefixMap prefixMapping)
{
//this( BufferingWriter.create(out) , vars, prefixMapping) ;
this( IO.asBufferedUTF8(out), vars, prefixMapping) ;
}
private BindingOutputStream(Writer out, List<Var> variables, PrefixMap prefixMapping)
{
bw = IO.wrap(out) ;
vars = variables ;
pmap = prefixMapping ;
nodeFormatter = new NodeFormatterTTL(null, pmap) ;
needOutputVars = (vars != null ) && vars.size() > 0 ;
}
public final void write(Binding binding) { send(binding) ; }
@Override
public void send(Binding binding)
{
try {
if ( needOutputPMap )
{
if ( pmap != null )
{
for ( Map.Entry<String, IRI> e : pmap.getMapping().entrySet() )
{
bw.write("PREFIX ") ;
bw.write(e.getKey()) ;
bw.write(": <") ;
bw.write(e.getValue().toASCIIString()) ;
bw.write("> .\n") ;
}
}
needOutputPMap = false ;
}
// Is the current VARS applicable?
if ( needVars(vars, binding) )
{
vars = Iter.toList(binding.vars()) ;
needOutputVars = true ;
}
if ( needOutputVars )
{
// Odd special case.
// No vars, empty binding.
if ( binding.size() == 0 && vars.size() == 0 )
{
bw.write(".\n") ;
needOutputVars = false ;
return ;
}
bw.write("VARS") ;
for ( Var v2 : vars )
{
bw.write(" ?") ;
bw.write(v2.getVarName()) ;
}
bw.write(" .\n") ;
needOutputVars = false ;
}
for ( Var v : vars )
{
Node n = binding.get(v) ;
if ( n == null )
{
bw.write("- ") ;
continue ;
}
// NodeFormatters should write safe bNode labels.
nodeFormatter.format(bw, n) ;
bw.write(" ") ;
}
bw.write(".\n") ;
} catch (IOException ex)
{
throw new RiotException(ex) ;
}
}
private static boolean needVars(List<Var> vars, Binding binding)
{
if ( vars == null ) return true ;
for ( Var v : vars )
{
if ( ! binding.contains(v) )
return true ;
}
return false ;
}
@Override
public void flush()
{
IO.flush(bw) ;
}
@Override
public void close()
{
IO.close(bw) ;
}
public List<Var> getVars()
{
return vars ;
}
public void setVars(List<Var> vars)
{
this.vars = vars ;
}
public PrefixMap getPrefixMap()
{
return pmap ;
}
public void setPrefixMap(PrefixMap pmap)
{
this.pmap = pmap ;
this.needOutputPMap = true ;
}
}