code: public void close( int port ) {
      for (Iterator i = _listeners.keySet().iterator(); i.hasNext(); ) {
        Object k = i.next();
        Object s = _listeners.get(k);
        if (s instanceof SocketHandler) {
          SocketHandler sh = (SocketHandler)s;
          if (port == -1 || sh.isPort( port )) {
            sh.interrupt();
            sh.close();
            _transactions.remove( s );
            _listeners.remove( k );
          }
        }
      }
    }
docs: Closes a port.  All connections on this port will be closed.
  
  @param port The port to close.  A value of less than -1 closes all ports