java-simple-serial-connector read/write server

Question

I have modified the example shown on https://code.google.com/p/java-simple-serial-connector/wiki/jSSC_examples to show read/write from java program. I can run the program, however the data I send using serialPort.writeString("HelloWorld"); does not seem to be read in the SerialPortReader event class. Could any one please point what the issue is ?

 public class SerialReaderWriter {

static SerialPort serialPort;

public static void main(String[] args) {
    serialPort = new SerialPort("COM1"); 
    try {
        serialPort.openPort();
        serialPort.setParams(9600, 8, 1, 0);
        //Preparing a mask. In a mask, we need to specify the types of events that we want to track.
        //Well, for example, we need to know what came some data, thus in the mask must have the
        //following value: MASK_RXCHAR. If we, for example, still need to know about changes in states 
        //of lines CTS and DSR, the mask has to look like this: SerialPort.MASK_RXCHAR + SerialPort.MASK_CTS + SerialPort.MASK_DSR
        int mask = SerialPort.MASK_RXCHAR;
        //Set the prepared mask
        serialPort.setEventsMask(mask);
        //Add an interface through which we will receive information about events
        serialPort.addEventListener(new SerialPortReader());

        serialPort.writeString("HelloWorld");
    }
    catch (SerialPortException ex) {
        System.out.println(ex);
    }
}

static class SerialPortReader implements SerialPortEventListener {

    public void serialEvent(SerialPortEvent event) {
        //Object type SerialPortEvent carries information about which event occurred and a value.
        //For example, if the data came a method event.getEventValue() returns us the number of bytes in the input buffer.
        System.out.println(event.getEventType());
        if(event.isRXCHAR()){
            if(event.getEventValue() == 10){
                try {
                    String data= serialPort.readString();
                    System.out.println(data);
                }
                catch (SerialPortException ex) {
                    System.out.println(ex);
                }
            }
        }
        //If the CTS line status has changed, then the method event.getEventValue() returns 1 if the line is ON and 0 if it is OFF.
        else if(event.isCTS()){
            if(event.getEventValue() == 1){
                System.out.println("CTS - ON");
            }
            else {
                System.out.println("CTS - OFF");
            }
        }
        else if(event.isDSR()){
            if(event.getEventValue() == 1){
                System.out.println("DSR - ON");
            }
            else {
                System.out.println("DSR - OFF");
            }
        }
    }
}

}

Solution

You can't read data from the same port where you write(COM1 here). I have followed the below steps for reading and writing using JSSC.

Fake your serial port with SerialPortMonitor.

1. Send data from COM2 from the SerialPortMonitor device installed.

2. Mode->Spy would show your written string "HelloWorld" and received String "OK"

Make the below modifications and check your code:

serialPort.setFlowControlMode(SerialPort.FLOWCONTROL_RTSCTS_IN |
                                 SerialPort.FLOWCONTROL_RTSCTS_OUT);

serialPort.writeBytes("HelloWorld");//Write data to port
PortReader portReader=new PortReader(serialPort)
serialPort.addEventListener(portReader, SerialPort.MASK_RXCHAR);
int[][] eventArray=serialPort.waitEvents()
for (int i = 0; i < eventArray.length; i++) {
    if ((eventArray[i][0] > 0) ) {
    serialPort.eventListener.serialEvent(new SerialPortEvent("COM1", eventArray[i][0], eventArray[i][1])); // wait for the listener event to complete
        }
    }

The port reader class: (You were missing the Override annotation and passing in the serial port)

public class PortReader implements SerialPortEventListener{
SerialPort serialPort
public PortReader(){}
public PortReader(SerialPort serialPort){this.serialPort=serialPort}
    @Override
    public void serialEvent(SerialPortEvent event) {
    if(event.isRXCHAR() && event.getEventValue() > 0) {
            try {
                String receivedData = this.serialPort.readString(event.getEventValue());
                System.out.println("Received response: " + receivedData);
                this.serialPort.closePort();//Close serial port
            }
            catch (SerialPortException ex) {
                System.out.println("Error in receiving string from COM-port: " + ex);
                this.serialPort.closePort();//Close serial port
            }
        }
    }

}

Comments

[user207421]

Add this why? Some explanation is required, not just "it worked for me".