Answer to Question #249479 in Java | JSP | JSF for Locos

Question

Write a menu driven program in Java to automate the ATM operations by

demonstrating the concepts of interfaces. And create custom exceptions to

deal with the following situations

a. Invalid PIN number is entered more than 3 times

b. Withdraw operation when balance amount < withdraw amount

Answer 1

public class InvalidPINException extends RuntimeException{
    public InvalidPINException(){
        super("The number of attempts has been exceeded.");
    }
}

public class WithdrawOperationException extends RuntimeException{
    public WithdrawOperationException(){
        super("The amount is greater than balance. ");
    }
}

public interface Operation {
    boolean withdraw(double amount);

    boolean deposit(double amount);

    boolean enterPIN(int pin);

    double getBalance();
}

public class ATM implements Operation {

    private static final int PIN = 0000;
    private double balance;
    private int pinAttempts;
    private boolean signIn;

    public ATM(double balance) {
        this.balance = balance;
        pinAttempts = 3;
        signIn = false;
    }

    @Override
    public boolean withdraw(double amount) {
        if (amount > 0 && signIn) {
            if (amount > balance) {
                throw new WithdrawOperationException();
            }
            balance -= amount;
            return true;
        }
        return false;
    }

    @Override
    public boolean deposit(double amount) {
        if (amount > 0 & signIn) {
            balance += amount;
            return true;
        }
        return false;
    }

    @Override
    public boolean enterPIN(int pin) {
        if (pinAttempts == 0) {
            throw new InvalidPINException();
        }
        if (pin == PIN) {
            signIn = true;
            return true;
        } else {
            pinAttempts--;
            return false;
        }
    }

    @Override
    public double getBalance() {
        if (signIn) {
            return balance;
        } else {
            return -1;
        }
    }
}

import java.util.Scanner;

public class Main {
    public static void main(String[] args) {
        Scanner in = new Scanner(System.in);
        ATM atm = new ATM(100);
        String input;
        while (true) {
            System.out.println("1. Enter PIN\n" + "2. Withdraw\n" +
                    "3. Deposit\n" + "4. Balance\n" + "0. Exit");
            input = in.nextLine();
            switch (input) {
                case "1":
                    System.out.print("Enter 4 digit PIN: ");
                    input = in.nextLine();
                    if (atm.enterPIN(Integer.parseInt(input))) {
                        System.out.println("PIN is valid.");
                    } else {
                        System.out.println("PIN is invalid.");
                    }
                    break;
                case "2":
                    System.out.print("Enter the amount to withdraw: ");
                    input = in.nextLine();
                    if (atm.withdraw(Double.parseDouble(input))) {
                        System.out.println("Success.");
                    }else{
                        System.out.println("Fail.");
                    }
                    break;
                case "3":
                    System.out.print("Enter the amount to deposit: ");
                    input = in.nextLine();
                    if (atm.deposit(Double.parseDouble(input))) {
                        System.out.println("Success.");
                    }else{
                        System.out.println("Fail.");
                    }
                    break;
                case "4":
                    System.out.println("Balance: " + atm.getBalance());
                    break;
                case "5":
                    System.exit(0);
                    break;
            }
        }
    }
}