private Set<String> extractVars(String query) {
log.debug(" {}", query);
Query q = QueryFactory.create(query);
Element element = q.getQueryPattern();
ElementWalker.walk(element, collector);
Set<String> vars = collector.getVariables();
log.debug(" > {}", vars);
return vars;
}
@After
public void after() {
collector.reset();
}