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Problem with OWL-S API an PreconditionCheck Example

From: Robert Langner <robert.langner@freenet.de>
Date: Fri, 9 May 2008 11:49:02 +0200
To: <semantic-web@w3.org>
Message-ID: <002101c8b1b9$ea497d50$bedc77f0$@langner@freenet.de>
Hello,

 

 

i have a problem when executing the "PreconditionCheck"  Example from the

OWL-S API.

 

When I want to run it, this error occurs:

 

 

 

Precondition check disabled

 

---------------------------

 

Trying unsupported language pair...

 

Exception in thread "main" java.lang.NullPointerException

 

      at impl.jena.OWLModelImpl.isTrue(OWLModelImpl.java:946)

 

 
atimpl.owls.generic.expression.SWRLExpressionImpl.isTrue(SWRLExpressionImpl.
java:66)

 

      at reasoning.PreconditionCheck.run(PreconditionCheck.java:54)

 

      at reasoning.PreconditionCheck.main(PreconditionCheck.java:110)

 

 

 

Can someone help me?

 

 

 

Code of PreconditionCheck:

 

 

 

import java.net.URI;

 

 

 

import org.mindswap.exceptions.ExecutionException;

 

import org.mindswap.exceptions.PreconditionException;

 

import org.mindswap.owl.OWLFactory;

 

import org.mindswap.owl.OWLIndividual;

 

import org.mindswap.owl.OWLKnowledgeBase;

 

import org.mindswap.owls.OWLSFactory;

 

import org.mindswap.owls.process.Process;

 

import org.mindswap.owls.process.execution.ProcessExecutionEngine;

 

import org.mindswap.owls.service.Service;

 

import org.mindswap.query.ValueMap;

 

 

 

/**

 

 * 

 

 * Examples to show how services can be executed. Some examples of simple

execution monitoring is 

 

 * included. 

 

 * 

 

 * @author Evren Sirin

 

 */

 

public class PreconditionCheck {

 

      public void run() throws Exception {

 

            OWLKnowledgeBase kb = OWLFactory.createKB();

 

            ProcessExecutionEngine exec =
OWLSFactory.createExecutionEngine();     

 

            

 

            kb.setReasoner("Pellet");

 

 

 

            // language ontology

 

            String langOnt ="
<http://www.daml.org/2003/09/factbook/languages>
http://www.daml.org/2003/09/factbook/languages#";

 

            

 

            Service service
=kb.readService("http://www.mindswap.org/2004/owls/1.1/BabelFishTranslator.o
wl");

 

            Process process = service.getProcess();

 

 

 

            OWLIndividual English = kb.getIndividual(URI.create(langOnt
+"English"));

 

            OWLIndividual German = kb.getIndividual(URI.create(langOnt
+"German"));

 

            OWLIndividual Italian = kb.getIndividual(URI.create(langOnt
+"Italian"));

 

 

 

        ValueMap values = new ValueMap();

 

            

 

 

 

            exec.setPreconditionCheck( false );

 

            

 

            System.out.println( "Precondition check disabled" );

 

            System.out.println( "---------------------------" );

 

            

 

            try {                   

 

                  values.setDataValue(process.getInput("InputString"),
"ciaomondo!");         

 

 
values.setValue(process.getInput("InputLanguage"),Italian);           

 

 
values.setValue(process.getInput("OutputLanguage"),German);           

 

                  

 

                  System.out.println( "Trying unsupported language
pair...");

 

                System.out.println( "Precondition satisfied: "
+process.getCondition().isTrue( values ) );

 

            exec.execute(process, values);

 

            System.out.println("Execution successecful!");

 

        } catch(PreconditionException e) {

 

            System.out.println("Precondition evaluation failed!");

 

            System.out.println(e);

 

        } catch(ExecutionException e) {

 

            System.out.println("Execution failed!");

 

            System.out.println(e);

 

        }   

 

          System.out.println();

 

 

 

          exec.setPreconditionCheck( true );

 

          

 

          System.out.println( "Precondition check enabled" );

 

            System.out.println( "---------------------------" );

 

                

 

            try {                   

 

                  values.setDataValue(process.getInput("InputString"),
"ciaomondo!");         

 

 
values.setValue(process.getInput("InputLanguage"),Italian);           

 

 
values.setValue(process.getInput("OutputLanguage"),German);           

 

 

 

                  System.out.println( "Trying unsupported language
pair...");

 

                  System.out.println( "Precondition satisfied: "
+process.getCondition().isTrue( values ) );

 

            exec.execute(process, values);

 

            System.out.println("Execution successecful!");

 

        } catch(PreconditionException e) {

 

            System.out.println("Precondition evaluation failed!");

 

            System.out.println(e);

 

        } catch(ExecutionException e) {

 

            System.out.println("Execution failed!");

 

            System.out.println(e);

 

        }   

 

        

 

          System.out.println();

 

            try {                   

 

                  values.setDataValue(process.getInput("InputString"),
"ciaomondo!");         

 

 
values.setValue(process.getInput("InputLanguage"),Italian);           

 

 
values.setValue(process.getInput("OutputLanguage"),English);          

 

 

 

                System.out.println( "Trying supported language pair..." );

 

                System.out.println( "Precondition satisfied: "
+process.getCondition().isTrue( values ) );

 

            exec.execute(process, values);

 

            System.out.println("Execution successecful!");

 

        } catch(PreconditionException e) {

 

            System.out.println("Precondition evaluation failed!");

 

            System.out.println(e);

 

        } catch(ExecutionException e) {

 

            System.out.println("Execution failed!");

 

            System.out.println(e);

 

        }

 

      }     

 

      

 

      public static void main(String[] args) throws Exception {        

 

            PreconditionCheck test = new PreconditionCheck();

 

            

 

            test.run();       

 

      }

 

}

 
Received on Friday, 9 May 2008 10:57:26 GMT

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