code: public void setFacility(byte facility) {
  		if (facility < SyslogMessage.FACILITY_KERNAL_MESSAGE
  				|| facility > SyslogMessage.FACILITY_LOCAL_USE_7) {
  			throw new IllegalArgumentException("Not a valid facility.");
  		}
  
  		this.facility = facility;
  	}
docs: Set the facility that is used when sending message.
  
  @param facility
  the facility to set
  @throws IllegalArgumentException
  if the facility is not a valid one.