Main.java Source code

Introduction

Here is the source code for Main.java

Source

import java.text.ParseException;
import java.text.SimpleDateFormat;

import javax.swing.Box;
import javax.swing.InputVerifier;
import javax.swing.JComponent;
import javax.swing.JFormattedTextField;
import javax.swing.JFrame;
import javax.swing.JOptionPane;
import javax.swing.JTextField;
import javax.swing.border.EmptyBorder;
import javax.swing.text.MaskFormatter;

public class Main {
    SimpleDateFormat format = new SimpleDateFormat("dd/MM/yyyy");

    public Main() {
        JFormattedTextField formattedField = null;
        try {
            MaskFormatter dateMask = new MaskFormatter("##/##/####");
            formattedField = new JFormattedTextField(dateMask);
        } catch (ParseException ex) {
            System.out.println(ex);
        }
        formattedField.setColumns(10);
        formattedField.setInputVerifier(getInputVerifier());

        JTextField field = new JTextField(10);
        format.setLenient(false);

        Box box = Box.createVerticalBox();
        box.add(formattedField);
        box.add(Box.createVerticalStrut(10));
        box.add(field);
        box.setBorder(new EmptyBorder(10, 10, 10, 10));

        JFrame frame = new JFrame();
        frame.add(box);
        frame.pack();
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        frame.setVisible(true);
    }

    private InputVerifier getInputVerifier() {
        InputVerifier verifier = new InputVerifier() {
            @Override
            public boolean verify(JComponent input) {
                JFormattedTextField field = (JFormattedTextField) input;
                String text = field.getText();
                return isValidDate(text);
            }

            @Override
            public boolean shouldYieldFocus(JComponent input) {
                boolean valid = verify(input);
                if (!valid) {
                    JOptionPane.showMessageDialog(null, "Please enter a valid date in format dd/mm/yyyy");
                }
                return valid;
            }
        };
        return verifier;
    }

    public boolean isValidDate(String dateString) {
        try {
            format.parse(dateString);
            return true;
        } catch (ParseException ex) {
            return false;
        }
    }

    public static void main(String[] args) {
        new Main();
    }
}