Main.java Source code

Introduction

Here is the source code for Main.java

Source

import javax.swing.JFormattedTextField;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.text.MaskFormatter;
import java.awt.FlowLayout;
import java.text.AttributedCharacterIterator;
import java.text.FieldPosition;
import java.text.Format;
import java.text.NumberFormat;
import java.text.ParsePosition;

public class Main {
    public static void main(String[] args) throws Exception {
        JFrame frame = new JFrame();
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        frame.setSize(100, 75);
        JPanel content = new JPanel(new FlowLayout());
        frame.setContentPane(content);

        MaskFormatter formatter = new MaskFormatter("#");
        formatter.setValidCharacters("123456789");

        JFormattedTextField f1 = new JFormattedTextField(formatter);
        f1.setValue(null);
        f1.setColumns(1);

        content.add(f1);
        frame.setVisible(true);
    }

    private static Format createFormat() {
        NumberFormat format = NumberFormat.getInstance();
        format.setParseIntegerOnly(true);
        return new Format() {
            @Override
            public StringBuffer format(Object obj, StringBuffer toAppendTo, FieldPosition pos) {
                return format.format(obj, toAppendTo, pos);
            }

            @Override
            public AttributedCharacterIterator formatToCharacterIterator(Object obj) {
                return format.formatToCharacterIterator(obj);
            }

            @Override
            public Object parseObject(String source, ParsePosition pos) {
                int initialIndex = pos.getIndex();
                Object result = format.parseObject(source, pos);
                if (result != null && pos.getIndex() > initialIndex + 1) {
                    int errorIndex = initialIndex + 1;
                    pos.setIndex(initialIndex);
                    pos.setErrorIndex(errorIndex);
                    return null;
                }
                return result;
            }
        };
    }
}