17                 if (args.length != 2) {
 
   18                         throw new ValueExprEvaluationException(getURI() + 
" requires exactly 2 arguments, got " + args.length);
 
   21                 Integer value=Integer.valueOf(args[1].stringValue());
 
   22                 LiteralType l=LiteralRegistry.getLiteral(((Literal)args[0]).getDatatype().toString());
 
   23                 if(l instanceof VectorLiteral) {
 
   24                         Geometry geom=((VectorLiteral)l).read(args[0].stringValue());
 
   25                         Geometry result = 
relation(geom,value);
 
   26                         return valueFactory.createLiteral(((VectorLiteral) l).unparse(result),((Literal)args[0]).getDatatype());
 
   28                 throw new ValueExprEvaluationException(
"Argument given is not a geometry literal");
 
abstract Geometry relation(Geometry geom, Integer value)