Hello, friends
Sorry for the long post. I am into a java web project using Jena. The
architecture is MVC, and in de Model I am trying to use some javabeans to
access and perform some processing on a OWL and a RDF file. The logic is
somewhat simple, I have to extract a path from a simple ontology in OWL. So
I am using the findShortestPath from OntTools (Comments are in Portuguese,
and are just for debugging). However there is a weird thing. I got an error
if I write something as:
++++++++++++
package composicao.model;
import java.util.HashSet;
import java.util.Iterator;
import java.util.LinkedList;
import java.util.List;
import java.util.Set;
import java.util.*;
import com.hp.hpl.jena.ontology.OntModel;
import com.hp.hpl.jena.ontology.OntClass;
import com.hp.hpl.jena.ontology.OntModelSpec;
import com.hp.hpl.jena.ontology.OntTools.Path;
import com.hp.hpl.jena.ontology.OntTools.PredicatesFilter;
import com.hp.hpl.jena.rdf.model.*;
import com.hp.hpl.jena.rdf.model.Model;
import com.hp.hpl.jena.rdf.model.ModelFactory;
import com.hp.hpl.jena.rdf.model.RDFNode;
import com.hp.hpl.jena.rdf.model.Resource;
import com.hp.hpl.jena.rdf.model.Statement;
import com.hp.hpl.jena.util.iterator.Filter;
import com.hp.hpl.jena.vocabulary.OWL;
public class GeraSequenciaBean {
/*
* A Sequencia é definida aqui como o conjunto de de conceitos
* retirados da ontologia, a partir o inicial e do final.
*
*/
String filename;
OntModel m = ModelFactory.createOntologyModel(OntModelSpec.OWL_DL_MEM);
m.read(filename);
final Filter<Statement> ANY = Filter.any();
public Path SequenciaBean( Model m, Resource start, RDFNode end,
Filter<Statement> onPath ) {
List<Path> bfs = new LinkedList<Path>();
Set<Resource> seen = new HashSet<Resource>();
// initialize the paths
for (Iterator<Statement> i = m.listStatements( start, null,
(RDFNode) null ).filterKeep( onPath ); i.hasNext(); ) {
bfs.add( new Path().append( i.next() ) );
}
// search
Path solution = null;
while (solution == null && !bfs.isEmpty()) {
Path candidate = bfs.remove( 0 );
if (candidate.hasTerminus( end ) ) {
solution = candidate;
System.out.println("Solucao :"+ solution); //never
printed...
}
else {
Resource terminus = candidate.getTerminalResource();
if (terminus != null) {
seen.add( terminus );
// breadth-first expansion
for (Iterator<Statement> i =
terminus.listProperties().filterKeep( onPath ); i.hasNext(); ) {
Statement link = i.next();
// no looping allowed, so we skip this link if it
takes us to a node we've seen
if (!seen.contains( link.getObject() )) {
bfs.add( candidate.append( link ) );
//System.out.println("Passou aqui!");
// System.out.println("Caminho canditato :" +
candidate);
}
}
}
}
}
return solution;
}
}
++++++++++++++++++
java.lang.reflect.InvocationTargetException
at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
at
sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:57)
at
sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45)
at java.lang.reflect.Constructor.newInstance(Constructor.java:532)
at
org.eclipse.ve.internal.java.vce.launcher.remotevm.JavaBeansLauncher.main(JavaBeansLauncher.java:86)
Caused by: java.lang.Error: Unresolved compilation problems:
Syntax error on token(s), misplaced construct(s)
Syntax error on token "filename", VariableDeclaratorId expected after
this token
at composicao.model.GeraSequenciaBean.<init>(GeraSequenciaBean.java:34)
... 5 more
IWAV0048I Java Bean composicao.model.GeraSequenciaBean started with null
constructor
IWAV0052E Invocation Target Exception creating
composicao.model.GeraSequenciaBean
--
Herli Menezes
*Per Astra ad aspera.*
