Apache Jena

From BITPlan Wiki
Revision as of 11:02, 14 June 2020 by Mf (talk | contribs) (→‎Trying it)
Jump to navigation Jump to search

Tutorial examples

see https://jena.apache.org/tutorials/rdf_api.html

Script to compile and run tutorial examples

#!/bin/bash
# WF 2020-06-14
num=$1
pwd=$(pwd)
base=$pwd/apache-jena-3.15.0
cd $base/src-examples
echo compiling Tutorial $num
javac -cp "$base/lib/*" jena/examples/rdf/Tutorial$num.java
echo running Tutorial $num
java -cp ".:$base/lib/*" jena/examples/rdf/Tutorial$num

Tutorial03.java

Java Code

/** Tutorial 3 Statement attribute accessor methods
 */
public class Tutorial03 extends Object {
    public static void main (String args[]) {
    
        // some definitions
        String personURI    = "http://somewhere/JohnSmith";
        String givenName    = "John";
        String familyName   = "Smith";
        String fullName     = givenName + " " + familyName;
        // create an empty model
        Model model = ModelFactory.createDefaultModel();

        // create the resource
        //   and add the properties cascading style
        Resource johnSmith 
          = model.createResource(personURI)
                 .addProperty(VCARD.FN, fullName)
                 .addProperty(VCARD.N, 
                              model.createResource()
                                   .addProperty(VCARD.Given, givenName)
                                   .addProperty(VCARD.Family, familyName));
        
        // list the statements in the graph
        StmtIterator iter = model.listStatements();
        
        // print out the predicate, subject and object of each statement
        while (iter.hasNext()) {
            Statement stmt      = iter.nextStatement();         // get next statement
            Resource  subject   = stmt.getSubject();   // get the subject
            Property  predicate = stmt.getPredicate(); // get the predicate
            RDFNode   object    = stmt.getObject();    // get the object
            
            System.out.print(subject.toString());
            System.out.print(" " + predicate.toString() + " ");
            if (object instanceof Resource) {
                System.out.print(object.toString());
            } else {
                // object is a literal
                System.out.print(" \"" + object.toString() + "\"");
            }
            System.out.println(" .");
        }
    }
}

Trying it

./ct 03
compiling Tutorial 03
running Tutorial 03
http://somewhere/JohnSmith http://www.w3.org/2001/vcard-rdf/3.0#N 7555a24e-8f13-4508-91f0-9dfb26cd2239 .
http://somewhere/JohnSmith http://www.w3.org/2001/vcard-rdf/3.0#FN  "John Smith" .
7555a24e-8f13-4508-91f0-9dfb26cd2239 http://www.w3.org/2001/vcard-rdf/3.0#Family  "Smith" .
7555a24e-8f13-4508-91f0-9dfb26cd2239 http://www.w3.org/2001/vcard-rdf/3.0#Given  "John" .

Tutorial04.java

Java Code

/*
 * 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 jena.examples.rdf ;

import org.apache.jena.rdf.model.*;
import org.apache.jena.vocabulary.*;

/** Tutorial 4 - create a model and write it in XML form to standard out
 */
public class Tutorial04 extends Object {
    
    // some definitions
    static String tutorialURI  = "http://hostname/rdf/tutorial/";
    static String briansName   = "Brian McBride";
    static String briansEmail1 = "brian_mcbride@hp.com";
    static String briansEmail2 = "brian_mcbride@hpl.hp.com";
    static String title        = "An Introduction to RDF and the Jena API";
    static String date         = "23/01/2001";
    
    public static void main (String args[]) {
    
        // some definitions
        String personURI    = "http://somewhere/JohnSmith";
        String givenName    = "John";
        String familyName   = "Smith";
        String fullName     = givenName + " " + familyName;
        // create an empty model
        Model model = ModelFactory.createDefaultModel();

        // create the resource
        //   and add the properties cascading style
        Resource johnSmith 
          = model.createResource(personURI)
                 .addProperty(VCARD.FN, fullName)
                 .addProperty(VCARD.N, 
                              model.createResource()
                                   .addProperty(VCARD.Given, givenName)
                                   .addProperty(VCARD.Family, familyName));
        
        // now write the model in XML form to a file
        model.write(System.out);
    }
}

Trying it

./ct 04
compiling Tutorial 04
running Tutorial 04
<rdf:RDF
    xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#"
    xmlns:vcard="http://www.w3.org/2001/vcard-rdf/3.0#">
  <rdf:Description rdf:about="http://somewhere/JohnSmith">
    <vcard:N rdf:parseType="Resource">
      <vcard:Family>Smith</vcard:Family>
      <vcard:Given>John</vcard:Given>
    </vcard:N>
    <vcard:FN>John Smith</vcard:FN>
  </rdf:Description>
</rdf:RDF>

Tutorial05.java

Java Code

/*
 * 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 jena.examples.rdf ;

import org.apache.jena.rdf.model.*;
import org.apache.jena.util.FileManager;

import java.io.*;

/** Tutorial 5 - read RDF XML from a file and write it to standard out
 */
public class Tutorial05 extends Object {

    /**
        NOTE that the file is loaded from the class-path and so requires that
        the data-directory, as well as the directory containing the compiled
        class, must be added to the class-path when running this and
        subsequent examples.
    */    
    static final String inputFileName  = "vc-db-1.rdf";
                              
    public static void main (String args[]) {
        // create an empty model
        Model model = ModelFactory.createDefaultModel();

        InputStream in = FileManager.get().open( inputFileName );
        if (in == null) {
            throw new IllegalArgumentException( "File: " + inputFileName + " not found");
        }
        
        // read the RDF/XML file
        model.read(in, "");
                    
        // write it to standard out
        model.write(System.out);            
    }
}

Try it!

wget https://jena.apache.org/tutorials/sparql_data/vc-db-1.rdf
mv vc-db-1.rdf apache-jena-3.15.0/src-examples/
./ct 05
compiling Tutorial 05
running Tutorial 05

<rdf:RDF
    xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#"
    xmlns:vCard="http://www.w3.org/2001/vcard-rdf/3.0#">
  <rdf:Description rdf:about="http://somewhere/SarahJones">
    <vCard:N rdf:parseType="Resource">
      <vCard:Given>Sarah</vCard:Given>
      <vCard:Family>Jones</vCard:Family>
    </vCard:N>
    <vCard:FN>Sarah Jones</vCard:FN>
  </rdf:Description>
  <rdf:Description rdf:about="http://somewhere/JohnSmith">
    <vCard:N rdf:parseType="Resource">
      <vCard:Given>John</vCard:Given>
      <vCard:Family>Smith</vCard:Family>
    </vCard:N>
    <vCard:FN>John Smith</vCard:FN>
  </rdf:Description>
  <rdf:Description rdf:about="http://somewhere/MattJones">
    <vCard:N rdf:parseType="Resource">
      <vCard:Given>Matthew</vCard:Given>
      <vCard:Family>Jones</vCard:Family>
    </vCard:N>
    <vCard:FN>Matt Jones</vCard:FN>
  </rdf:Description>
  <rdf:Description rdf:about="http://somewhere/RebeccaSmith">
    <vCard:N rdf:parseType="Resource">
      <vCard:Given>Rebecca</vCard:Given>
      <vCard:Family>Smith</vCard:Family>
    </vCard:N>
    <vCard:FN>Becky Smith</vCard:FN>
  </rdf:Description>
</rdf:RDF>
Retrieved from "https://wiki.bitplan.com/index.php?title=Apache_Jena&oldid=12545"