public NLGElement getNLFromSingleClause(Element e) {
if (e instanceof ElementPathBlock) {
ElementPathBlock epb = (ElementPathBlock) e;
List<Triple> triples = new ArrayList<Triple>();
// get all triples. We assume that the depth of union is always 1
for (TriplePath tp : epb.getPattern().getList()) {
Triple t = tp.asTriple();
triples.add(t);
}
return getNLForTripleList(triples, "and");
} // if clause is union clause then we generate or statements
else if (e instanceof ElementUnion) {
CoordinatedPhraseElement cpe;
// cast to union
ElementUnion union = (ElementUnion) e;
List<Triple> triples = new ArrayList<Triple>();
// get all triples. We assume that the depth of union is always 1
for (Element atom : union.getElements()) {
ElementPathBlock epb = ((ElementPathBlock) (((ElementGroup) atom).getElements().get(0)));
if (!epb.isEmpty()) {
Triple t = epb.getPattern().get(0).asTriple();
triples.add(t);
}
}
return getNLForTripleList(triples, "or");
} // if it's a filter
else if (e instanceof ElementFilter) {
SPhraseSpec p = nlgFactory.createClause();
ElementFilter filter = (ElementFilter) e;
Expr expr = filter.getExpr();
return getNLFromSingleExpression(expr);
}
return null;
}
/* @see com.hp.hpl.jena.sparql.syntax.ElementVisitorBase#visit(com.hp.hpl.jena.sparql.syntax.ElementFilter) */
@Override
public void visit(final ElementFilter elementfilter) {
final Expr expr = elementfilter.getExpr();
final BuiltinAtom atom;
try {
if (expr instanceof Expression) // RDQL
{
final Expression e = (Expression) expr;
final SWRLDataObject arg1 = makeDataObject(e.getArg(0));
final SWRLDataObject arg2 = makeDataObject(e.getArg(1));
if (e instanceof Q_Equal) atom = swrlFactory.createEqual(arg1, arg2);
else if (e instanceof Q_NotEqual) atom = swrlFactory.createNotEqual(arg1, arg2);
else if (e instanceof Q_GreaterThan) atom = swrlFactory.createGreaterThan(arg1, arg2);
else if (e instanceof Q_GreaterThanOrEqual)
atom = swrlFactory.createGreaterThanOrEqual(arg1, arg2);
else if (e instanceof Q_LessThan) atom = swrlFactory.createLessThan(arg1, arg2);
else if (e instanceof Q_LessThanOrEqual)
atom = swrlFactory.createLessThanOrEqual(arg1, arg2);
else
throw new IllegalArgumentException(
"Unsupported constraint expression " + e + " used in RDQL query.");
} else if (expr.isFunction()) // SPARQL
{
final ExprFunction f = (ExprFunction) expr;
final SWRLDataObject arg1 = makeDataObject(f.getArg(0));
final SWRLDataObject arg2 = makeDataObject(f.getArg(1));
if (f instanceof E_Equals) atom = swrlFactory.createEqual(arg1, arg2);
else if (f instanceof E_NotEquals) atom = swrlFactory.createNotEqual(arg1, arg2);
else if (f instanceof E_GreaterThan) atom = swrlFactory.createGreaterThan(arg1, arg2);
else if (f instanceof E_GreaterThanOrEqual)
atom = swrlFactory.createGreaterThanOrEqual(arg1, arg2);
else if (f instanceof E_LessThan) atom = swrlFactory.createLessThan(arg1, arg2);
else if (f instanceof E_LessThanOrEqual)
atom = swrlFactory.createLessThanOrEqual(arg1, arg2);
else
throw new IllegalArgumentException(
"Unsupported constraint (filter) " + f + " used in SPARQL query.");
} else return;
atoms = atoms.cons(atom);
} catch (final URISyntaxException e) {
throw new IllegalArgumentException(e.getInput() + " is not a valid URI!");
}
}