public Boolean isWriteLocked(K token){
  RWLock<K> lock=locks.get(token);
  if (lock == null)   return null;
  return lock.isWriteLocked();
}

public Boolean isWriteLocked ( K token ) { RWLock < K > lock = locks . get ( token ) ; if ( lock == null ) return null ; return lock . isWriteLocked ( ) ; }
queries if the write lock is held by any thread on given lock token , returns null when lock with this token does not exists
