/*
* 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.
*/
// To do:
// Better detection of illegal characters in qnames (? and = for example)
package org.apache.jena.n3;
//import org.apache.commons.logging.*;
import java.io.OutputStream;
import java.io.Writer;
import org.apache.jena.JenaRuntime ;
import org.apache.jena.rdf.model.* ;
/** Entry point for N3 writers. This writer will choose the actual writer
* to use by looking at the system property
* <code>org.apache.jena.n3.N3JenaWriter.writer</code> to get the
* writer name.
* <p>
* The following N3 writers are provided:
* <ul>
* <li>N3-PP: Pretty Printer (the default)</li>
* <li>N3-PLAIN: Plain, record/frame-oriented format</li>
* <li>N3-TRIPLES: Triples, with prefixes.</li>
* </ul>
* </p>
*/
public class N3JenaWriter implements RDFWriter
{
//static Logger logger = LoggerFactory.getLogger(N3JenaWriter.class) ;
static public boolean DEBUG = false ;
// Note: properties are URIs, not java convention package/class names.
static protected final String propBase = "http://jena.hpl.hp.com/n3/properties/" ;
/** System property name that sets the default N3 writer name */
static public final String propWriterName = propBase+"writer" ;
/**
* General name for the N3 writer. Will make a decision on exactly which
* writer to use (pretty writer, plain writer or simple writer) when created.
* Default is the pretty writer but can be overridden with system property
* <code>org.apache.jena.n3.N3JenaWriter.writer</code>.
*/
static public final String n3Writer = "N3" ;
/**
* Name of the N3 pretty writer. The pretty writer
* uses a frame-like layout, with prefixing, clustering like properties
* and embedding one-referenced bNodes.
*/
static public final String n3WriterPrettyPrinter = "N3-PP" ;
/**
* Name of the N3 plain writer. The plain writer writes records
* by subject.
*/
static public final String n3WriterPlain = "N3-PLAIN" ;
/**
* Name of the N3 triples writer. This writer writes one line per statement,
* like N-Triples, but does N3-style prefixing.
*/
static public final String n3WriterTriples = "N3-TRIPLES" ;
/**
* Alternative name for the N3 triples writer.
*/
static public final String n3WriterTriplesAlt = "N3-TRIPLE" ;
/**
* Turtle writer.
* http://www.dajobe.org/2004/01/turtle/
*/
static public final String turtleWriter = "TURTLE" ;
static public final String turtleWriterAlt1 = "Turtle" ;
static public final String turtleWriterAlt2 = "TTL" ;
protected N3JenaWriterCommon writer = null ;
public N3JenaWriter() { writer = chooseWriter() ; }
public N3JenaWriter(N3JenaWriterCommon w) { writer = w ;}
N3JenaWriterCommon chooseWriter()
{
// Choose the writer
String writerName = JenaRuntime.getSystemProperty(propWriterName) ;
if ( writerName == null ||
writerName.equals("N3") || writerName.equals(n3WriterPrettyPrinter) )
return new N3JenaWriterPP() ;
if ( writerName.equalsIgnoreCase(n3WriterPlain) )
return new N3JenaWriterCommon() ;
if ( writerName.equalsIgnoreCase(n3WriterTriples) ||
writerName.equalsIgnoreCase(n3WriterTriplesAlt) )
return new N3JenaWriterTriples() ;
if ( writerName.equalsIgnoreCase(turtleWriter) )
{
N3JenaWriterPP w = new N3JenaWriterPP() ;
w.useWellKnownPropertySymbols = false ;
return w ;
}
// Don't know or default.
return new N3JenaWriterPP() ;
}
/** Write the model out in N3, encoded in in UTF-8
* @see #write(Model,Writer,String)
*/
@Override
public void write(Model model, Writer out, String base)
{
writer.write(model, out, base) ;
}
/** Write the model out in N3. The writer should be one suitable for UTF-8 which
* excludes a PrintWriter or a FileWriter which use default character set.
*
* Examples:
* <pre>
* try {
* Writer w = new BufferedWriter(new OutputStreamWriter(output, "UTF-8")) ;
* model.write(w, base) ;
* try { w.flush() ; } catch (IOException ioEx) {...}
* } catch (java.io.UnsupportedEncodingException ex) {} //UTF-8 is required so can't happen
* </pre>
* or
* <pre>
* try {
* OutputStream out = new FileOutputStream(file) ;
* Writer w = new BufferedWriter(new OutputStreamWriter(out, "UTF-8")) ;
* model.write(w, base) ;
* }
* catch (java.io.UnsupportedEncodingException ex) {}
* catch (java.io.FileNotFoundException noFileEx) { ... }
* </pre>
* @see #write(Model,Writer,String)
*/
@Override
public void write(Model model, OutputStream out, String base)
{
writer.write(model, out, base) ;
}
/**
* @see org.apache.jena.rdf.model.RDFWriter#setProperty(java.lang.String, java.lang.Object)
*/
@Override
public Object setProperty(String propName, Object propValue)
{
return writer.setProperty(propName, propValue) ;
}
/**
* @see org.apache.jena.rdf.model.RDFWriter#setErrorHandler(org.apache.jena.rdf.model.RDFErrorHandler)
*/
@Override
public RDFErrorHandler setErrorHandler(RDFErrorHandler errHandler)
{
return writer.setErrorHandler(errHandler) ;
}
}