Explain the code

Question

Hi there
Could someone explain the following piece of code to me.
Yes I have looked everywhere but it is very hard to get some decent information on the serial port.
Thanks in advance
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();
            if (portId.getPortType() == CommPortIdentifier.PORT_SERIAL) {
                // if (portId.getName().equals("COM1")) {
                if (portId.getName().equals("/dev/term/a")) {
                    try {
                        serialPort = (SerialPort)
                            portId.open("SimpleWriteApp", 2000);
                    } 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) {}
                    try {
                        outputStream.write(messageString.getBytes());
                    } catch (IOException e) {}
}

Answer 1

Thanks for that
Will you give me an explanation of the following:
import java.io.*;
import java.util.*;
import javax.comm.*;
public class SimpleRead implements Runnable, SerialPortEventListener {
    static CommPortIdentifier portId;
    static Enumeration portList;
    InputStream inputStream;
    SerialPort serialPort;
    Thread readThread;
    public static void main(String[] args) {
        portList = CommPortIdentifier.getPortIdentifiers();
        while (portList.hasMoreElements()) {
            portId = (CommPortIdentifier) portList.nextElement();
            if (portId.getPortType() == CommPortIdentifier.PORT_SERIAL) {
                // if (portId.getName().equals("COM1")) {
                if (portId.getName().equals("/dev/term/a")) {
                    SimpleRead reader = new SimpleRead();
    public SimpleRead() {
        try {
            serialPort = (SerialPort) portId.open("SimpleReadApp", 2000);
        } catch (PortInUseException e) {}
        try {
            inputStream = serialPort.getInputStream();
        } catch (IOException e) {}
     try {
            serialPort.addEventListener(this);
     } catch (TooManyListenersException e) {}
        serialPort.notifyOnDataAvailable(true);
        try {
            serialPort.setSerialPortParams(9600,
                SerialPort.DATABITS_8,
                SerialPort.STOPBITS_1,
                SerialPort.PARITY_NONE);
        } catch (UnsupportedCommOperationException e) {}
        readThread = new Thread(this);
        readThread.start();
    public void run() {
        try {
            Thread.sleep(20000);
        } catch (InterruptedException e) {}
    public void serialEvent(SerialPortEvent event) {
        switch(event.getEventType()) {
        case SerialPortEvent.BI:
        case SerialPortEvent.OE:
        case SerialPortEvent.FE:
        case SerialPortEvent.PE:
        case SerialPortEvent.CD:
        case SerialPortEvent.CTS:
        case SerialPortEvent.DSR:
        case SerialPortEvent.RI:
        case SerialPortEvent.OUTPUT_BUFFER_EMPTY:
            break;
        case SerialPortEvent.DATA_AVAILABLE:
            byte[] readBuffer = new byte[20];
            try {
                while (inputStream.available() > 0) {
                    int numBytes = inputStream.read(readBuffer);
                System.out.print(new String(readBuffer));
            } catch (IOException e) {}
            break;
}