我无法更新 ontology 模型

Question

我在 Protege 中制作了一个 Ontologu 并导入到 Eclipse.My ontology 已经有 10 个实例我想添加更多 instances.The 下面的一段代码 添加实例 到 class（名词）的 ontology。执行后它不会更新 ontology 模型并显示相同数量的实例。

  public static void main(String[] args) throws OWLException, IOException{
  OWLOntologyManager manager = OWLManager.createOWLOntologyManager();

  File file = new File("D:\word.owl");{  
      OntModel model=ModelFactory.createOntologyModel(OntModelSpec.OWL_MEM_RULE_INF);
       System.out.println("Model is called successfully");
    OWLOntology ont = manager.loadOntologyFromOntologyDocument(file);
    System.out.println("Loaded ontology: " + ont);

   String SOURCE = ("D:\word.owl");
   String NS = SOURCE;
   OntModel base = ModelFactory.createOntologyModel(OntModelSpec.OWL_MEM_RULE_INF);
   base.read( SOURCE, "" );

OntModel inf =ModelFactory.createOntologyModel(OntModelSpec.OWL_MEM_RULE_INF, base );

 OntClass Noun = base.getOntClass( NS + "Noun" );
 Individual jack = base.createIndividual( NS + "Jack", Noun );
 Individual Helley = base.createIndividual( NS + "Helley", Noun );  
  manager.saveOntology(ont);

 System.out.println("Number of individuals: " + ont.getIndividualsInSignature().size());

    }
  }
 }

输出

  Model is called successfully
  Loaded ontology: 
 Number of individuals: 10

Answer 1

我不使用那个 API 但我可以看到你的问题。

在代码的开头，您创建了一个 OWLOntology 对象：

OWLOntology ont = manager.loadOntologyFromOntologyDocument(file);

这就是问题所在，您没有更改 ont 代码中的任何地方，因此当您调用下面的行时，它只会 show/save 您从文件中加载的 10 个相同的人在代码的开头：

manager.saveOntology(ont);

System.out.println("Number of individuals: " + ont.getIndividualsInSignature().size());

因此，要解决此问题，您需要以某种方式修改 ont 以在使用上述行之前包含新的 Individual。

Answer 2

更新代码 它在线程中给出异常 "main" java.lang.NullPointerException 在 Mgt.main(Mgt.java:29)

import java.io.FileWriter;
import java.io.IOException;
import java.io.InputStream;
import org.apache.jena.ontology.Individual;
import org.apache.jena.ontology.OntClass;
import org.apache.jena.ontology.OntModel;
import org.apache.jena.ontology.OntModelSpec;
import org.apache.jena.rdf.model.ModelFactory;
import org.apache.jena.util.FileManager;
public class Mgt {
static OntModel jenaModel = null;
public static void main(String[] args) throws Exception{
    String file =("D:\word.owl");
     jenaModel = ModelFactory.createOntologyModel(OntModelSpec.OWL_MEM_RULE_INF);

            InputStream in = FileManager.get().open(file);
            try 
            {
                jenaModel.read(in, null);
            } 
            catch (Exception e) 
            {
                e.printStackTrace();
            }
            System.out.println("Ontology " + file + " loaded.");
            OntClass Noun = jenaModel.getOntClass( "http://www.semanticweb.org/Word#Noun" );
            Individual Organization = Noun.createIndividual(file + "Organization");
            FileWriter out = null;
            try {
              // XML format - long and verbose
              out = new FileWriter( file);
              jenaModel.write( out, "RDF/XML" );

            }
            finally {
              if (out != null) {
                try {out.close();
                } catch (IOException ignore) {}
              }
            }
          }
         }

Answer 3

这个有效：

import java.io.FileWriter;
import java.io.InputStream;

import org.apache.jena.ontology.Individual;
import org.apache.jena.ontology.OntClass;
import org.apache.jena.ontology.OntModel;
import org.apache.jena.ontology.OntModelSpec;
import org.apache.jena.rdf.model.ModelFactory;
import org.apache.jena.util.FileManager;
import org.apache.jena.vocabulary.RDF;

public class Mgt {

    public static void main(String[] args) throws Exception {
        String namespace = "http://www.semanticweb.org/Word#";
        String file = "word.owl";
        OntModel jenaModel = ModelFactory.createOntologyModel(OntModelSpec.OWL_MEM_RULE_INF);

        InputStream in = FileManager.get().open(file);
        jenaModel.read(in, null);
        OntClass Noun = jenaModel.getOntClass(namespace + "Noun");
        Individual Organization = Noun.createIndividual(namespace + "Organization");
        jenaModel.add(Organization, RDF.type, Noun);
        FileWriter out = new FileWriter("word.out.owl");
        jenaModel.getWriter("RDF/XML-ABBREV").write(jenaModel, out, namespace);
        out.close();
    }
}

注意命名空间与文件名无关。

我无法更新 ontology 模型

I am not able to update ontology model

java

ontology

owl-api

apache-jena