How to catch *all* characters sent to Text field from a HID barcode scanner? - eclipse

Question

I need to capture input from a barcode scanner. Up until now the input has been just simple alphanum text which I have captured in one Text field. I added a ModifyListener to the Text field and am able to see the input arrive. That has worked fine.
I now need to handle a more complex matrix code which contains values for multiple fields. The values are separated by non-printable characters such as RS, GS and EOT (0x1E, 0x1D, 0x04). The complete data stream has a well-defined header and an EOT at the end, so I am hoping that I can detect barcode input as opposed to manual input.
When a barcode is detected, I can use the record separators RS to split the message and insert the values into the relevant Text fields.
However, the standard key handler on the Text controls ignore these non-printable characters and they do not appear in the controls text. This makes it impossible to proceed as planned.
How could I modify these Text fields to accept and store all characters? Or is there an alternative approach I could use?

Answer 1

This is the code I used to handle the barcode stream.
public class Main
{
static StringBuilder sb = new StringBuilder();
public static void main(String[] args)
{
Display d = new Display();
Shell shell = new Shell(d);
shell.setLayout(new FillLayout());
Text text = new Text(shell, 0);
text.addListener(SWT.KeyDown, new Listener()
{
#Override
public void handleEvent(Event e)
{
// only accept real characters
if (e.character != 0 && e.keyCode < 0x1000000)
{
sb.append(e.character);
String s = sb.toString();
// have start and end idents in buffer?
int i = s.indexOf("[)>");
if (i > -1)
{
int eot = s.indexOf("\u0004", i);
if (eot > -1)
{
String message = s.substring(i, eot + 1);
handleMessageHere(message);
// get ready for next message
sb = new StringBuilder();
}
}
}
}
});
shell.open();
while (!shell.isDisposed())
{
if (!d.readAndDispatch())
d.sleep();
}
}