PackageDescr packageDescr = parser.parse(null, drl);
PackageBuilder builder = new PackageBuilder();
builder.addPackage(packageDescr);
Package pkg = builder.getPackage();
ReteooRuleBase ruleBase = (ReteooRuleBase) RuleBaseFactory.newRuleBase(RuleBase.RETEOO);
ruleBase.addPackage(pkg);
final ReteooVisitor visitor = new ReteooVisitor( graph );
visitor.visit( ruleBase );
BaseVertex root = visitor.getRootVertex();