FastCash.java

import javax.swing.*;
import java.awt.event.*;
import java.sql.*;

public class FastCash extends JFrame implements ActionListener {
    JButton b100, b500, b1000, b2000, b5000, b10000, back;
    String cardNumber;

    FastCash(String cardNumber) {
        this.cardNumber = cardNumber;

        setTitle("Fast Cash");
        setLayout(null);

        JLabel label = new JLabel("Select Amount");
        label.setBounds(140, 20, 150, 30);
        add(label);

        b100 = new JButton("Rs 100");
        b500 = new JButton("Rs 500");
        b1000 = new JButton("Rs 1000");
        b2000 = new JButton("Rs 2000");
        b5000 = new JButton("Rs 5000");
        b10000 = new JButton("Rs 10000");
        back = new JButton("Back");

        JButton[] buttons = {b100, b500, b1000, b2000, b5000, b10000};
        int y = 70;
        for (JButton btn : buttons) {
            btn.setBounds(100, y, 180, 30);
            btn.addActionListener(this);
            add(btn);
            y += 40;
        }

        back.setBounds(100, y + 10, 180, 30);
        back.addActionListener(this);
        add(back);

        setSize(400, 400);
        setLocation(450, 200);
        setVisible(true);
    }

    public void actionPerformed(ActionEvent ae) {
        String amt = ae.getActionCommand().substring(3).trim(); // Rs 100 -> 100

        if (ae.getSource() == back) {
            setVisible(false);
            new Transaction(cardNumber);
            return;
        }

        try {
            Conn conn = new Conn();
            ResultSet rs = conn.s.executeQuery("SELECT * FROM bank WHERE card_number = '" + cardNumber + "'");
            int balance = 0;
            while (rs.next()) {
                String type = rs.getString("type");
                int amount = Integer.parseInt(rs.getString("amount"));
                balance += type.equals("Deposit") ? amount : -amount;
            }

            int withdrawAmt = Integer.parseInt(amt);
            if (withdrawAmt > balance) {
                JOptionPane.showMessageDialog(null, "Insufficient Balance.");
                return;
            }

            String query = "INSERT INTO bank (card_number, date, type, amount) VALUES ('" + cardNumber + "', NOW(), 'Withdraw', '" + amt + "')";
            conn.s.executeUpdate(query);
            JOptionPane.showMessageDialog(null, "Rs. " + amt + " Withdrawn Successfully");
            setVisible(false);
            new Transaction(cardNumber);

        } catch (Exception e) {
            e.printStackTrace();
        }
    }

    public static void main(String[] args) {
        new FastCash("1234567890123456");
    }
}