Difference between revisions of "Apache Jena"

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Line 407: Line 407:
 
   Matt Jones
 
   Matt Jones
 
   Becky Smith
 
   Becky Smith
 +
</source>
 +
== Tutorial08.java ==
 +
=== Java Code ===
 +
<source lang='java'>
 +
/*
 +
* 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 org.apache.jena.vocabulary.*;
 +
 +
import java.io.*;
 +
 +
 +
/** Tutorial 8 - demonstrate Selector methods
 +
*/
 +
public class Tutorial08 extends Object {
 +
   
 +
    static final String inputFileName = "vc-db-1.rdf";
 +
   
 +
    public static void main (String args[]) {
 +
        // create an empty model
 +
        Model model = ModelFactory.createDefaultModel();
 +
     
 +
        // use the FileManager to find the input file
 +
        InputStream in = FileManager.get().open(inputFileName);
 +
        if (in == null) {
 +
            throw new IllegalArgumentException( "File: " + inputFileName + " not found");
 +
        }
 +
       
 +
        // read the RDF/XML file
 +
        model.read( in, "" );
 +
       
 +
        // select all the resources with a VCARD.FN property
 +
        // whose value ends with "Smith"
 +
        StmtIterator iter = model.listStatements(
 +
            new
 +
                SimpleSelector(null, VCARD.FN, (RDFNode) null) {
 +
                    @Override
 +
                    public boolean selects(Statement s) {
 +
                            return s.getString().endsWith("Smith");
 +
                    }
 +
                });
 +
        if (iter.hasNext()) {
 +
            System.out.println("The database contains vcards for:");
 +
            while (iter.hasNext()) {
 +
                System.out.println("  " + iter.nextStatement()
 +
                                              .getString());
 +
            }
 +
        } else {
 +
            System.out.println("No Smith's were found in the database");
 +
        }           
 +
    }
 +
}
 +
</source>
 +
=== Try it ! ===
 +
<source lang='bash'>
 +
./ct 08
 +
compiling Tutorial 08
 +
running Tutorial 08
 +
The database contains vcards for:
 +
  Becky Smith
 +
  John Smith
 
</source>
 
</source>

Revision as of 12:08, 14 June 2020

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>

Tutorial06.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 org.apache.jena.vocabulary.*;

import java.io.*;

/** Tutorial navigating a model
 */
public class Tutorial06 extends Object {
    
    static final String inputFileName = "vc-db-1.rdf";
    static final String johnSmithURI = "http://somewhere/JohnSmith";
    
    public static void main (String args[]) {
        // create an empty model
        Model model = ModelFactory.createDefaultModel();
       
        // use the FileManager to find the input file
        InputStream in = FileManager.get().open(inputFileName);
        if (in == null) {
            throw new IllegalArgumentException( "File: " + inputFileName + " not found");
        }
        
        // read the RDF/XML file
        model.read(new InputStreamReader(in), "");
        
        // retrieve the Adam Smith vcard resource from the model
        Resource vcard = model.getResource(johnSmithURI);

        // retrieve the value of the N property
        Resource name = (Resource) vcard.getRequiredProperty(VCARD.N)
                                        .getObject();
        // retrieve the given name property
        String fullName = vcard.getRequiredProperty(VCARD.FN)
                               .getString();
        // add two nick name properties to vcard
        vcard.addProperty(VCARD.NICKNAME, "Smithy")
             .addProperty(VCARD.NICKNAME, "Adman");
        
        // set up the output
        System.out.println("The nicknames of \"" + fullName + "\" are:");
        // list the nicknames
        StmtIterator iter = vcard.listProperties(VCARD.NICKNAME);
        while (iter.hasNext()) {
            System.out.println("    " + iter.nextStatement().getObject()
                                            .toString());
        }
    }
}

Try it!

./ct 06
compiling Tutorial 06
running Tutorial 06
The nicknames of "John Smith" are:
    Adman
    Smithy

Tutorial07.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 org.apache.jena.vocabulary.*;

import java.io.*;

/** Tutorial 7 - selecting the VCARD resources
 */
public class Tutorial07 extends Object {
    
    static final String inputFileName = "vc-db-1.rdf";
    
    public static void main (String args[]) {
        // create an empty model
        Model model = ModelFactory.createDefaultModel();
       
        // use the FileManager to find the input file
        InputStream in = FileManager.get().open(inputFileName);
        if (in == null) {
            throw new IllegalArgumentException( "File: " + inputFileName + " not found");
        }
        
        // read the RDF/XML file
        model.read( in, "");
        
        // select all the resources with a VCARD.FN property
        ResIterator iter = model.listResourcesWithProperty(VCARD.FN);
        if (iter.hasNext()) {
            System.out.println("The database contains vcards for:");
            while (iter.hasNext()) {
                System.out.println("  " + iter.nextResource()
                                              .getRequiredProperty(VCARD.FN)
                                              .getString() );
            }
        } else {
            System.out.println("No vcards were found in the database");
        }            
    }
}

Try it !

compiling Tutorial 07
running Tutorial 07
The database contains vcards for:
  Sarah Jones
  John Smith
  Matt Jones
  Becky Smith

Tutorial08.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 org.apache.jena.vocabulary.*;

import java.io.*;


/** Tutorial 8 - demonstrate Selector methods
 */
public class Tutorial08 extends Object {
    
    static final String inputFileName = "vc-db-1.rdf";
    
    public static void main (String args[]) {
        // create an empty model
        Model model = ModelFactory.createDefaultModel();
       
        // use the FileManager to find the input file
        InputStream in = FileManager.get().open(inputFileName);
        if (in == null) {
            throw new IllegalArgumentException( "File: " + inputFileName + " not found");
        }
        
        // read the RDF/XML file
        model.read( in, "" );
        
        // select all the resources with a VCARD.FN property
        // whose value ends with "Smith"
        StmtIterator iter = model.listStatements(
            new 
                SimpleSelector(null, VCARD.FN, (RDFNode) null) {
                    @Override
                    public boolean selects(Statement s) {
                            return s.getString().endsWith("Smith");
                    }
                });
        if (iter.hasNext()) {
            System.out.println("The database contains vcards for:");
            while (iter.hasNext()) {
                System.out.println("  " + iter.nextStatement()
                                              .getString());
            }
        } else {
            System.out.println("No Smith's were found in the database");
        }            
    }
}

Try it !

./ct 08
compiling Tutorial 08
running Tutorial 08
The database contains vcards for:
  Becky Smith
  John Smith
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