Semweb4j/filesQueries/step2

Up | Previous step | Next step

Step 2: Serialization syntaxes

RDF2Go offers different syntaxes for serialization of a RDF model. You could choose to serialize in one syntax for this tool and another syntax for that tool to post-process your RDF models.

N3

Now, we will write to System.out:

OutputStreamWriter writer = new OutputStreamWriter(System.out);
model.writeTo( writer, Syntax.Ntriples);

Model.writeTo can be called with a StreamWriter (like above) or with an OutStream (see below).

RDF/XML

model.writeTo( writer, Syntax.RdfXml);

Turtle

model.writeTo( writer, Syntax.Turtle);

TriG

model.writeTo( writer, Syntax.Trig);

TriX

Because Trix is not implemented in Jena 2.4, we don't do this:

model.writeTo( writer, Syntax.Trix);

using a String

You can easily serialize into a String like this:

String turtleSerialization = model.serialize(Syntax.Turtle);

the complete program

package org.ontoware.semweb4j.lessons.lesson2;

import java.io.IOException;
import java.io.OutputStreamWriter;

import org.ontoware.rdf2go.RDF2Go;
import org.ontoware.rdf2go.exception.ModelRuntimeException;
import org.ontoware.rdf2go.model.Model;
import org.ontoware.rdf2go.model.Syntax;
import org.ontoware.rdf2go.model.node.URI;

public class Step2 {

Now we skip some code as it's the same as in step 1...

After adding statements to our model:

		// serializing model with every syntax possible
		OutputStreamWriter writer = new OutputStreamWriter(System.out);
		writer.write("Ntriples following:\n");
		model.writeTo( writer, Syntax.Ntriples);
		writer.write("\nRdfXml following:\n");
		model.writeTo( writer, Syntax.RdfXml);
		writer.flush();

		// it works also with System.out (which is an OutStream):
		writer.write("\nTurtle following:\n");
		model.writeTo(System.out, Syntax.Turtle);
		writer.write("\nTrig following:\n");
		model.writeTo(System.out, Syntax.Trig);
		
		// because Trix is not implemented in Jena24, we don't do this:
		// model.writeTo( writer, Syntax.Trix);

		// It's also possible to serialize into a String:
		String turtleSerialization = model.serialize(Syntax.Turtle);

output

The output of this program is:

Ntriples following:
<http://xam.de/foaf.rdf.xml#i> <http://xmlns.com/foaf/0.1/#term_name> "Max V\u00F6lkel" .
<http://xam.de/foaf.rdf.xml#i> <http://xmlns.com/foaf/0.1/#term_currentProject> <http://semweb4j.org> .

RdfXml following:
<rdf:RDF
    xmlns:foaf="http://xmlns.com/foaf/0.1/"
    xmlns:j.0="http://xmlns.com/foaf/0.1/#"
    xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#"
    xmlns:xsd="http://www.w3.org/2001/XMLSchema#"
    xmlns:rdfs="http://www.w3.org/2000/01/rdf-schema#" >
  <rdf:Description rdf:about="http://xam.de/foaf.rdf.xml#i">
    <j.0:term_name>Max Völkel</j.0:term_name>
    <j.0:term_currentProject rdf:resource="http://semweb4j.org"/>
  </rdf:Description>
</rdf:RDF>

Turtle following:
@prefix xsd:     <http://www.w3.org/2001/XMLSchema#> .
@prefix rdfs:    <http://www.w3.org/2000/01/rdf-schema#> .
@prefix rdf:     <http://www.w3.org/2000/01/rdf-schema#> .
@prefix foaf:    <http://xmlns.com/foaf/0.1/> .
@prefix :        <#> .

<http://xam.de/foaf.rdf.xml#i>
      <http://xmlns.com/foaf/0.1/#term_currentProject>
              <http://semweb4j.org> ;
      <http://xmlns.com/foaf/0.1/#term_name>
              "Max Völkel" .

Note that there will be a text like this before your output:

01.01.2007 12:34:56 org.ontoware.rdf2go.RDF2Go checkModelFactory
INFO: Using ModelFactory 'class org.ontoware.rdf2go.impl.jena24.ModelFactoryImpl' which was loaded via org.ontoware.rdf2go.impl.StaticBinding.

if you don't specify the adapter (/ ModelFactoryImpl / triple store).

We will never mention these 2 lines if they appear in the output, so remember they don't indicate bugs, warnings, etc..

Sorry that Trig syntax is not listed in output here, that's coming soon.