@SuppressWarnings("unchecked") void addMaster(final AbstractMasterTask master){
  if (master == null)   throw new IllegalArgumentException();
  if (masters.putIfAbsent(master.hashCode(),master) == null) {
    masterCreateCount.incrementAndGet();
  }
}

@ SuppressWarnings ( "unchecked" ) void addMaster ( final AbstractMasterTask master ) { if ( master == null ) throw new IllegalArgumentException ( ) ; if ( masters . putIfAbsent ( master . hashCode ( ) , master ) == null ) { masterCreateCount . incrementAndGet ( ) ; } }
a new master task declares itself to this statistics object using this method . this allows the statistics object to report on the # of master tasks , their queue sizes , and the sizes of their sink queues .
