private boolean isRootFinished(Procedure<?> proc) {
    Procedure<?> rootProc = procedures.get(proc.getRootProcId());
    return rootProc == null || rootProc.isFinished();
  }
Scheduler/Queue that contains runnable procedures.
hbase-procedure/src/main/java/org/apache/hadoop/hbase/procedure2/ProcedureExecutor.java