How to accept only numeric values between 0 and 8 in JTextfied?

Question

I want my jtextfield to accept only numerical values between 0 and the MAX value specified in the code example below.

Let´s say the MAX variable is set to 8, as below. Then I just want it to be possible to enter a numeric value between 0 and 8. In my code example below you can type 88, 77, 66 etc and that should not be possible. I have no clue how I can make it so it only accepts values between 0 and MAX.

import javax.swing.*;
import javax.swing.text.*;

public class DocumentDemo extends JFrame {
    public static void main(String[] args) {
        new DocumentDemo();
    }

    final int MAX = 8;

    public DocumentDemo() {
        this.setVisible(true);
        JTextField textField = new JTextField();

        ((AbstractDocument)textField.getDocument()).setDocumentFilter(
                new DocumentFilter() {

                    @Override
                    public void replace(FilterBypass fb, int offset, int length, String text, AttributeSet attrs) throws BadLocationException {
                        int len = text.length();
                        boolean isValidValue = true;
                        for(int i = 0; i < len; i++) {
                            if(!Character.isDigit(text.charAt(i))){
                                isValidValue = false;
                            }
                        }

                        if(isValidValue && Integer.parseInt(text) > MAX) {
                            isValidValue = false;
                        }

                        if(isValidValue && fb.getDocument().getText(0, fb.getDocument().getLength()).length() > String.valueOf(MAX).length()) {
                            isValidValue = false;
                        }

                        if(isValidValue) {
                            super.replace(fb, offset, length, text, attrs);
                        }
                    }
                }
        );
        textField.setColumns(5);
        this.add(textField);
        this.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        this.pack();
    }
}

Answer 1

JFormattedTextField sounds like what you want.

NumberFormatter nf = new NumberFormatter();  
nf.setMinimum(new Integer(0));  
nf.setMaximum(new Integer(8));  
JFormattedTextField field = new JFormattedTextField(nf);  

Edit: showed how to set min, max