@Override
  public void addFront(Iterator<Procedure> procedureIterator) {
    schedLock();
    try {
      int count = 0;
      while (procedureIterator.hasNext()) {
        Procedure procedure = procedureIterator.next();
        if (LOG.isTraceEnabled()) {
          LOG.trace("Wake " + procedure);
        }
        push(procedure, /* addFront= */ true, /* notify= */false);
        count++;
      }
      wakePollIfNeeded(count);
    } finally {
      schedUnlock();
    }
  }
Add the procedure to the queue. NOTE: this method is called with the sched lock held.
@param procedure the Procedure to add
@param addFront  true if the item should be added to the front of the queue
hbase-procedure/src/main/java/org/apache/hadoop/hbase/procedure2/AbstractProcedureScheduler.java