private final Splitter splitter;
private final Set<String> blacklist;
private final Set<String> whitelist;
protected BlackAndWhitelistVisitor(OperatorPlan plan) throws FrontendException {
super(plan, new DepthFirstWalker(plan));
blacklist = Sets.newHashSet();
whitelist = Sets.newHashSet();
splitter = Splitter.on(',').trimResults().omitEmptyStrings();
init();