private void addCollectFileSinkUrisRules(Map<SemanticRule, SemanticNodeProcessor> opRules, SemanticNodeProcessor np) {
    opRules.put(new RuleRegExp("R1", FileSinkOperator.getOperatorName() + ".*"), np);
  }
Notifiers to synchronize resource localization across threads. If one thread is localizing
a file, other threads can wait on the corresponding notifier object instead of just sleeping
before re-checking HDFS. This is used just to avoid unnecesary waits; HDFS check still needs
to be performed to make sure the resource is there and matches the expected file.
ql/src/java/org/apache/hadoop/hive/ql/exec/tez/DagUtils.java