making a formatted text box that only takes 4 integers as input?

[asifzbaig]

Buddies i have to use a formatted text box that only takes integer values, also i want to fix the values to only 4 integers, neither less nor more than this.
Please help me how can i do this...

Thank you all.. in advance

[eRaaaa]

Use a DocumentFilter!

 class DocumentSizeFilter extends DocumentFilter {
    private final int maxCharacters;
    private final String pattern;
    public DocumentSizeFilter(final int maxChars, final String pattern) {
        maxCharacters = maxChars;
        this.pattern = pattern;
    }
    @Override
    public void replace(FilterBypass fb, int offs, int length, String str, AttributeSet a)
            throws BadLocationException {
        if (str.matches(pattern) && (fb.getDocument().getLength() + str.length() - length) <= maxCharacters) {
            super.replace(fb, offs, length, str, a);
        } else {
            Toolkit.getDefaultToolkit().beep(); // :D
        }
    }
}

Example to use:

......
		JTextField textfield = new JTextField(4);
		((AbstractDocument) textfield.getDocument()).setDocumentFilter(new DocumentSizeFilter(4, "\\d+"));

[asifzbaig]

Hey thankyou very much... it works very good...
Since i m using NetBeans IDE the design i have created is by using swing pallete, now if i create the text field as said by you than how can i placed it onto the desired position??
Is there a way to transform the textfield in my design with this one???

[asifzbaig]

Thank you very much for your help, it finally works as i need it to be....
I use the Customize Code property of the textfield and change the values there as given by you....

Thanks again

[asifzbaig]

Hey do me one more favour please, give me the value of pattern such that i can be pass it through the constructor of DocumentSizeFilter so that i can only input the values as:
AB91
GH78

etc etc..........please help me
and thank you

[eRaaaa]

only two upper case letters and two digits (in this order) or what ?

"[A-Z]{2}\\d{2}"

Pattern (Java Platform SE 6)

[asifzbaig]

Dear, the second one is not working :-(
I dont know why but it does not taking any input................ no chars and no digits....
Can i have to change the range value of that constructor too???

[eRaaaa]

it is clear that this does not work!
(it should work only if you copy and paste the whole correct string into the textfield!!!)

You can customize the code or? You dont have to use String.matches(...) and a given Regex. You could iterate over the string, and check if the first character is an upper case, the second, and so on...

or use two if statements.. like if((str.length() == 1 || str.length() == 2 ) && str.matches([A-Z+]) else if((str.length() == 3 || str.lenght() == 4 ) && str.matches(the pattern shown above)...

or or or :) Be creative !

[asifzbaig]

Hmm i will trying the same.....but not very familiar with java....
By the way thanks alot...

[eRaaaa]

Try for example:

    @Override
    public void replace(FilterBypass fb, int offs, int length, String str2, AttributeSet a)
            throws BadLocationException {
    	String str = fb.getDocument().getText(0, fb.getDocument().getLength()) + str2;
    	if((str.length() == 1 || str.length() == 2 ) && str.matches("[A-Z]+") || ((str.length() == 3 || str.length() == 4 ) && str.matches("[A-Z]{2}\\d{1,2}"))){
            super.replace(fb, offs, length, str2, a);
        } else {
           Toolkit.getDefaultToolkit().beep(); // :D
        }
    }

:D