OWL-S 前置条件表达式提取

Question

我正在尝试将前提条件的表达式提取为 SWRL 以制作 IOPE 网络服务OWL-S 匹配

这是我的代码

final OWLIndividualList<Condition> cs = service.getProcess().getConditions();
final ArrayList<ArrayList<URI>> conditions = new ArrayList<ArrayList<URI>>();
    for (final Condition<?> c : cs){
        if (c.canCastTo(Condition.SWRL.class)){ 
            final Condition.SWRL sc = c.castTo(Condition.SWRL.class);
            for (final Atom a : sc.getBody()){
                a.accept(new AtomVisitor() {
                public void visit(final IndividualPropertyAtom atom){
                    URI aux = null;
                    final ArrayList<URI> uris = new ArrayList<URI>();
                    URI a1 = aux.create((atom.getArgument1().getNamespace().toString() 
                    +atom.getArgument1().toString()));
                    URI a2 = aux.create((atom.getArgument2().getNamespace().toString() 
                    +atom.getArgument2().toString()));
                    URI p = aux.create(atom.getPropertyPredicate().toString());
                    uris.add(p);
                    uris.add(a1);
                    uris.add(a2);
                    conditions.add(uris);
               }
               public void visit(final DataPropertyAtom atom) { }
               public void visit(final SameIndividualAtom atom) { }
               public void visit(final DifferentIndividualsAtom atom) { }
               public void visit(final ClassAtom atom) { }
               public void visit(final BuiltinAtom atom)    { }
          });
      }
  }

}

我在“final Atom a : sc.getBody()”java.lang.NullPointerException 上得到一个 java.lang.NullPointerException

OWL-S 前置条件语句

     <expr:SWRL-Condition rdf:ID="DifferentLocations">
         <expr:expressionLanguage rdf:resource="http://www.daml.org/services/owl- 
              s/1.2/generic/Expression.owl#SWRL"/>
         <expr:expressionBody rdf:parseType="Literal">
            <swrl:AtomList>
                <rdf:first>
                    <swrl:DifferentIndividualsAtom>
                         <swrl:argument1 rdf:resource="#_GEOPOLITICAL-ENTITY"/>
                         <swrl:argument2 rdf:resource="#_GEOPOLITICAL-ENTITY1"/>
                    </swrl:DifferentIndividualsAtom>
                </rdf:first>
                <rdf:rest rdf:resource="http://www.w3.org/1999/02/22-rdf-syntax-ns#nil"/>
             </swrl:AtomList>
         </expr:expressionBody>
      </expr:SWRL-Condition>

拜托，我需要帮助

Answer 1

此问题与 java 代码无关，而是与 OWLS-S 文件语法相关。您可以通过替换来解决此问题：

  <expr:expressionBody rdf:parseType="Literal">

持有 SWRL 前提条件（或最终结果），作者：

  <expr:expressionObject>

OWL-S 前置条件表达式提取

OWL-S Precondition expression extracting

expression

swrl