if (cat instanceof ComplexCat) {
Category resCat = ((ComplexCat)cat).getResult();
retval=this.getSubjectFeature(resCat);
}
else if (cat instanceof AtomCat) {
AtomCat ac = (AtomCat) cat;
FeatureStructure fs = ac.getFeatureStructure();
for(String attr: fs.getAttributes()){
if(attr.equals("sbj")){
retval=fs.getValue(attr).toString();
break;
}