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Establishing a Connection using javax.comm (commapi)

Hi all. I know how to claim com ports and then send data into them using the comm api. But I want to be able to establish a connection between 2 com ports (running the same program at both ends). I only want to send data into the port if i know the other end is listening. Also if the connection was broken I want to be able to warn the user. Does anyone know how i can implement this. Do i need to implement some sort of handshaking? Any code examples much appreciated.
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import java.io.*;
import java.util.*;
import javax.comm.*;


public class SimpleWrite {
    static Enumeration portList;
    static CommPortIdentifier portId;
    static String messageString = "Hello, world!\n";
    static SerialPort serialPort;
    static OutputStream outputStream;

    public static void main(String[] args) {
        portList = CommPortIdentifier.getPortIdentifiers();

        while (portList.hasMoreElements()) {
            portId = (CommPortIdentifier) portList.nextElement();
             System.out.println("Port type: " + portId.getPortType());
             if (portId.getPortType() == CommPortIdentifier.PORT_SERIAL) {
                 
                System.out.println("Port name: " + portId.getName());
                if (portId.getName().equals("/dev/term/a")) {
                    try {
                            serialPort = (SerialPort)
                            portId.open("SimpleWriteApp", 2000);
                            System.out.println("COM port  " + portId.getPortType() + "opened");                          
                    } catch (PortInUseException e) {}
                   
                    try {
                        outputStream = serialPort.getOutputStream();
                    } catch (IOException e) {}
                    try {
                        serialPort.setSerialPortParams(9600,
                            SerialPort.DATABITS_8,                            
                            SerialPort.STOPBITS_1,                            
                            SerialPort.PARITY_NONE);                            
                    } catch (UnsupportedCommOperationException e) {}
                   
                    System.out.println("Data bits set to 8");
                    System.out.println("Stop bits set to 1");
                    System.out.println("Parity set to NONE");
                   
                    try {
                       System.out.println("Writing " + messageString);
                       outputStream.write(messageString.getBytes());
                    } catch (IOException e) {}
                }
            }
        }
    }
}


Here in this example you open the output stream and then write the string to it

so simply calling Input stream and do the same procedure for read.


Regards,

Freedom