JFormattedTextField - verfiier problem

Question

I have a problem using JFormattedTextField for data entry,
(see _postcodeTextField below ).
Specifiying a MaskFormatter does restirct the data accepted, in this case to 4 numbers.
My problem lies with the InputVerifier.
When I shift the focus (using the <TAB> key) the verifier is invoked. If the
input is invalid (e.g. 356 which consists of 3 numbers not 4) then as expected
there is a Beep and a message dialog appears.
Once the dialog is closed, the focus returns to the _postcodeTextField as expected.
However, if I then enter a number, it does not appear, but if I enter the number again,
it appears.
Why is the first number lost?
This code has been derived from examples found on the Sun site.
Curiously there is mention of "focus-transfer problems" with the verifier.
I like the ability to define an input mask to restirct data entry, but I am
disappointed by the problems I have encountered in verification.
I have tried a FocusHandler (extends FocusAdapter) but this also has problems.
The new JFormattedTextField looks capable of providing the functionality I require,
but it appears to have its quirks and will need a patch in time.
Meanwhile, any suggestions?
_postcodeTextField = getTextFieldWithFormat("####");
_postcodeTextField.setToolTipText("4 digit code e.g. 4065");
private JFormattedTextField getTextFieldWithFormat( String format )
MaskFormatter formatter = null;
try
formatter = new MaskFormatter(format);
catch (java.text.ParseException exc)
System.err.println("formatter is bad: " + exc.getMessage());
JFormattedTextField ftf = new JFormattedTextField(formatter);          
ftf.setFont( new Font( "Arial", Font.PLAIN, 14 ) );
ftf.setColumns(format.length());      
ftf.setInputVerifier(new FormattedTextFieldVerifier());
return ftf;     
} // getTextFieldWithFormat()
public class FormattedTextFieldVerifier extends InputVerifier
public class FormattedTextFieldVerifier extends InputVerifier
public boolean verify(JComponent input)
if (input instanceof JFormattedTextField)
JFormattedTextField ftf = (JFormattedTextField) input;
try
ftf.commitEdit();
catch (ParseException pe )
return false;
return true;               
} // verify()          
public boolean shouldYieldFocus(JComponent input)
boolean inputOK = verify(input);
if (!inputOK)
//Avoid possible focus-transfer problems when bringing up
//the dialog by temporarily removing the input verifier.
//This is a workaround for bug #4532517.
input.setInputVerifier(null);
Toolkit.getDefaultToolkit().beep();
//Display a warning message.
String message = "Please try again.";
JOptionPane.showMessageDialog(null, message,
"Invalid Value", JOptionPane.WARNING_MESSAGE);
//Reinstall the input verifier.
input.setInputVerifier(this);
return inputOK;
} // shouldYieldFocus()
} // FormattedTextFieldVerifier class

Answer 1

(this could be a duplicate post
first reply disappeared into the ether)
Meanwhile I consider you have earnt the 10 Duke points I attached to the\is topic.
I imagine I have to award them to you or something? How do I do that?I don't really know, but keep them for when someone spends a fair bit of
time and effort solving a problem for you.
In this case it was just a matter of testing the code and reporting the result.
Thanks for the offer.