Serial Comunnication between Java and Arduino

I'm writing a code to send and receive data using the serial port of an arduino, for that I'm using the jserialcomm library. For sending and receiving data, I'm using a DataListener of the library which detect whether or not a bunch of bytes has been sent or received, the problem is that DataListener uses a method called getListneningEvents to list the events which the the DataListener will be able to use, but you can only return one of them because is overwriting an abstract method who returns only one integer, the documentation says that you can return one or more events but I trully don't know how to do it, if you can help with that pls.

public class MessageListener implements SerialPortMessageListener{
@Override
public int getListeningEvents() { 
    return SerialPort.LISTENING_EVENT_DATA_WRITTEN;
    // return SerialPort.LISTENING_EVENT_DATA_RECEIVED;
    // I want to return both methods
}


@Override
public byte[] getMessageDelimiter(){ 
    return new byte[] {
        (byte)0x0A
    }; 
}

@Override
public boolean delimiterIndicatesEndOfMessage(){ 
    return true; 
}

@Override
public void serialEvent(SerialPortEvent event){
    switch (event.getEventType()) {
        //Evento para datos enviados
        case SerialPort.LISTENING_EVENT_DATA_WRITTEN:
            System.out.println("All bytes were successfully transmitted!");
            break;
        
        //Evento para datos recibidos
        case SerialPort.LISTENING_EVENT_DATA_RECEIVED:
            byte[] delimitedMessage = event.getReceivedData();
            String mensaje = new String(delimitedMessage, StandardCharsets.UTF_8);
            mensaje = mensaje.replace("\n", "");
            System.out.println("Received the following delimited message: " + mensaje);
            break;
    }
    
}

}

Documentation of that DataListener