events - Barcode Scanner implementation on Java

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Answer 1

I recently had to implement a scanner system to interact with java.

I used Honeywell Voyager MS9540 USB barcode scanner.

As a default the scanner sent the data straight as keyboard input - no driver required.

But it was very easy to get this model to interact directly with java rather than using a keyboard hook (to use the barcodes as variables in java, as you mentioned).

This model has a setting to emulate a serial port, you can then read the scanned data using the javax.comm package. For me, this was much better than a keyboard hook to get the barcode data because the program does not need the focus before being able to interpret a scan (I would not want to create a global keyboard hook).

My java program reads all input from the specified serial port and writes the barcode to a database. I also setup the program to pass any unrecognized barcode scans to the keyboard (any barcode that my app did not create - I used a distinct signature on my barcodes) this was so it would work as a regular barcode scanner for any other apps that might read barcodes from the keyboard.

You could probably read data directly from any USB scanner (without the serial port emulation that this model has) by doing some intensive JNI coding but I wasn't prepared to take the time to work out the native code.

To configure this particular model for serial port emulation all you do is scan a specific barcode in this document with the scanner you want to configure. It is the barcode titled "Serial Emulation Mode".

This scanner does require a driver for serial port emulation. I found the implementation instructions and the needed drivers here (under the "software" tab). Download the package titled: "Honeywell Scanning and Mobility (HSM) USB Serial Driver". The PDF titled "HSM USB Serial Driver Getting Started Guide" had the instructions.

If you are not familiar with the javax.comm API. Please read the intro in this example by Rick Proctor - it tells you where to get the jar and where to put the files (javax.comm does not come standard with most java packages).

I'm sure there are other scanner models around that have serial port emulation (I don't work for Honeywell).

Here's a somewhat stripped down version of my barcode reader class:

package scanhandler;


import java.awt.AWTException;
import java.awt.Robot;
import java.io.FileInputStream;
import java.io.IOException;
import java.io.InputStream;
import java.sql.Connection;
import java.util.Enumeration;
import java.util.Properties;
import java.util.TooManyListenersException;
import javax.comm.CommPortIdentifier;
import javax.comm.PortInUseException;
import javax.comm.SerialPort;
import javax.comm.SerialPortEvent;
import javax.comm.SerialPortEventListener;
import javax.comm.UnsupportedCommOperationException;

public class ScanHandler implements Runnable, SerialPortEventListener {

    private static CommPortIdentifier   myCommPortIdentifier;
    private static Enumeration          portList;
    private static String               TimeStamp;
    private static String               driverClass;
    private static String               connectionString;
    private static String               comPort;    

    private Connection                  myConnection;
    private InputStream                 myInputStream;
    private Robot                       myRobot;
    private SerialPort                  mySerialPort;
    private Thread                      myThread;


    public ScanHandler() {

        // open serial port
        try {
            TimeStamp = new java.util.Date().toString();
            mySerialPort = (SerialPort) myCommPortIdentifier.open("ComControl", 2000);
            //System.out.println(TimeStamp + ": " + myCommPortIdentifier.getName() + " opened for scanner input");
        } catch (PortInUseException e) {
            e.printStackTrace();
        }

        // get serial input stream
        try {
            myInputStream = mySerialPort.getInputStream();
        } catch (IOException e) {
            e.printStackTrace();
        }

        // add an event listener on the port
        try {
            mySerialPort.addEventListener(this);
        } catch (TooManyListenersException e) {
            e.printStackTrace();
        }
        mySerialPort.notifyOnDataAvailable(true);

        // set up the serial port properties
        try {
            mySerialPort.setSerialPortParams(9600,
                SerialPort.DATABITS_8,
                SerialPort.STOPBITS_1,
                SerialPort.PARITY_NONE);
            mySerialPort.setDTR(false);
            mySerialPort.setRTS(false);

        } catch (UnsupportedCommOperationException e) {
            e.printStackTrace();
        }

        // make a robot to pass keyboard data
        try {
            myRobot = new Robot();
        } catch (AWTException e) {
            e.printStackTrace();
        }

        // create the thread
        myThread = new Thread(this);
        myThread.start();
    }

    public void run() {
        try {
            Thread.sleep(100);
        } catch (InterruptedException e) {}
    }

    // on scan
    public void serialEvent(SerialPortEvent event) {

        if (event.getEventType() == SerialPortEvent.DATA_AVAILABLE) {

            StringBuilder myStringBuilder = new StringBuilder();
            int c;
            try {

                // append the scanned data onto a string builder
                while ((c = myInputStream.read()) != 10){
                   if (c != 13)  myStringBuilder.append((char) c);
                }               

                // send to keyboard buffer if it the barcode doesn't start with '5'
                if (myStringBuilder.charAt(0) != '5') {

                    for (int i = 0; i < myStringBuilder.length(); i++) {
                        myRobot.keyPress((int) myStringBuilder.charAt(i));
                        myRobot.keyRelease((int) myStringBuilder.charAt(i));
                    }

                // here's the scanned barcode as a variable!
                } else {
                    TimeStamp = new java.util.Date().toString();
                    System.out.println(TimeStamp + ": scanned input received:" + myStringBuilder.toString());                    
                }

                // close the input stream
                myInputStream.close();

            } catch (IOException e) {
                e.printStackTrace();
            }
        }
    }

    public static void main(String[] args) {

        // read ScanHandler properties
        Properties myProperties = new Properties();
        try {
            myProperties.load(new FileInputStream("config.properties"));
            comPort             = myProperties.getProperty("ScanHandler.comPort");
        } catch (IOException e) {
            e.printStackTrace();
        }              

        try {

            // get our pre-defined COM port
            myCommPortIdentifier = CommPortIdentifier.getPortIdentifier(comPort);
            ScanHandler reader = new ScanHandler();

        } catch (Exception e) {
            TimeStamp = new java.util.Date().toString();
            System.out.println(TimeStamp + ": " + comPort + " " + myCommPortIdentifier);
            System.out.println(TimeStamp + ": msg1 - " + e);
        }
    };    
}