Question

Java project:

A Bank Transaction System For A Regional Bank User Story A regional rural bank CEO wants to modernize banking experience for his customers by providing a computer solution for them to post the bank transactions in their savings and checking accounts from the comfort of their home. He has a vision of a system, which begins by displaying the starting balances for checking and savings account for a customer. The application first prompts the user to enter the information for a transaction, including whether a withdrawal or deposit is to be made, whether the transaction will be posted to the checking or savings account, and the amount of the transaction. When the user (customer) finishes deposits and withdrawals, the application displays the fees and payments for the month followed by the final balances for the moth. The application needs to be friendly and it needs to validate the user entries. Operation • The application begins by displaying the starting balances for a checking and savings account. • The application prompts the user to enter the information for a transaction, including whether a withdrawal or deposit is to be made, whether the transaction will be posted to the checking or savings account, and the amount of the transaction. • When the user finishes entering deposits and withdrawals, the application displays the fees and payments for the month followed by the final balances for the month.

A typical customer interaction:

Welcome to the Account application
Starting Balances Checking: $1,000.00 Savings: $1,000.00
Enter the transactions for the month
Withdrawal or deposit? (w/d): w Checking or savings? (c/s): c Amount?: 500
Continue? (y/n): y
Withdrawal or deposit? (w/d): d Checking or savings? (c/s): s Amount?: 200
Continue? (y/n): n
Monthly Payments and Fees Checking fee: $1.00 Savings interest payment: $12.00
Final Balances Checking: $499.00 Savings: $1,212.00

Assumptions • There is no database for this system, that means nothing is stored or read from • The starting deposits are $1000 for both the accounts for each run. Banking fee is $1/month, and interest earned is 1%/month • Bank fee is flat fee and charged only once at the end of transactions for the checking account only • Interest earned is calculated only once for the balance left in the savings account only Requirement 1) The CEO of this bank has hired you. Your job is to write an object oriented Java program to provide the above experience, simulating a simplified banking experience. You need to identify the classes and its hierarchy (use inheritance). You should also have proper interfaces identified, which mandates all the required behaviors as described in the problem domain 2) Provide an application (user) class as well, which uses these classes to complete the user interaction. Your program needs to be idiot proof, meaning, you need to validate user entries and guide the user properly to enter correct information. 3) Overdraft is not allowed and final balance should not be negative for any accounts

Answer 1

AccountBalance.java

import java.text.NumberFormat;

public class AccountBalance {

    public static void main(String[] args) {

        CheckingAccount checkingAccount = new CheckingAccount(1.00);
        SavingsAccount savingsAccount = new SavingsAccount(0.01);

        checkingAccount.setBalance(1000.00);
        savingsAccount.setBalance(1000.00);

        NumberFormat currency = NumberFormat.getCurrencyInstance();

        Console.displayLine("Welcome to the Account application\n");
        Console.displayLine("Starting Balances");
        displayBalances(checkingAccount, savingsAccount);
        Console.displayLine();
        Console.displayLine("Enter the transactions for the month\n");

        String choice = "y";

        while (choice.equalsIgnoreCase("y")) {
            String transactionType = Console.getString("Withdrawal or deposit? (w/d): ", "w", "d");
            String accountType = Console.getString("Checking or savings? (c/s): ", "c", "s");
            double amount = Console.getDouble("Amount? ");

//            if (transactionType.equalsIgnoreCase("w")) {
//                amount = Console.getWithdrawalDouble("Amount? ");
//            } else {
//                amount = Console.getDouble("Amount? ");
//            }
            Console.displayLine();

            // code to perform transaction
            Account account = null;
            if (accountType.equalsIgnoreCase("c")) {
                account = checkingAccount;
            } else {
                account = savingsAccount;
            }

            if (transactionType.equalsIgnoreCase("w")) {
                if (amount > account.getBalance()) {
                    Console.displayLine("Amount entered exceeds account balance.\nPlease enter a valid amount.\n");
                } else {
                    account.withdraw(amount);
                }
            } else {
                account.deposit(amount);
            }

            choice = Console.getString("Continue? (y/n): ", "y", "n");
            Console.displayLine();
        }

        // apply interest and fees
        checkingAccount.subtractMonthlyFee();
        savingsAccount.setMonthlyIntPayment(savingsAccount.getBalance(), savingsAccount.getMonthlyIntRate());
        savingsAccount.applyPaymentToBalance();

        Console.displayLine("\nMonthly Payments and Fees");
        Console.displayLine("Checking Fee:                " + currency.format(checkingAccount.getMonthlyFee()));
        Console.displayLine("Savings Interest Payment:    " + currency.format(savingsAccount.getMonthlyIntPayment()));
        Console.displayLine();
        Console.displayLine("Final Balances");
        displayBalances(checkingAccount, savingsAccount);

    }

    private static void displayBalances(CheckingAccount ca, SavingsAccount sa) {
        NumberFormat currency = NumberFormat.getCurrencyInstance();
        Console.displayLine("Checking: " + currency.format(ca.getBalance()));
        Console.displayLine("Savings: " + currency.format(sa.getBalance()));
    }

}

CheckingAccount.java

public class CheckingAccount extends Account {
   double monthlyFee;

   public CheckingAccount(double fee) {
       monthlyFee = fee;
   }

   public double getMonthlyFee() {
       return monthlyFee;
   }
  
   public void subtractMonthlyFee () {
       setBalance(getBalance() - monthlyFee);
   }
}

SavingsAccount.java

public class SavingsAccount extends Account {
   double monthlyIntRate;
   double monthlyIntPayment;
  
   public SavingsAccount(double rate) {
       monthlyIntRate = rate;
   }

   public double getMonthlyIntRate() {
       return monthlyIntRate;
   }

   public void setMonthlyIntPayment(double balance, double rate) {
       monthlyIntPayment = balance * rate;
   }

   public double getMonthlyIntPayment() {
       return monthlyIntPayment;
   }
  
   public void applyPaymentToBalance() {
       setBalance(getBalance() + getMonthlyIntPayment());
   }
}

Account.java

public class Account implements Balancable, Withdrawable, Depositable {

   protected double balance = 0;

   @Override
   public void deposit(double amount) {
       // TODO Auto-generated method stub
       balance += amount;
   }

   @Override
   public void withdraw(double amount) {
       // TODO Auto-generated method stub
       balance -= amount;
   }

   @Override
   public double getBalance() {
       // TODO Auto-generated method stub
       return balance;
   }

   @Override
   public void setBalance(double amount) {
       // TODO Auto-generated method stub
       balance = amount;
   }
}

Balancable.java

public interface Balancable {
   double getBalance();
   void setBalance(double amount);
}

Withdrawable.java

public interface Withdrawable {
   void withdraw(double amount);
}

Console.java

import java.util.Scanner;

public class Console {

    private static Scanner sc = new Scanner(System.in);
  
    public static void displayLine() {
        System.out.println();
    }

    public static void displayLine(String s) {
        System.out.println(s);
    }

    public static String getString(String prompt) {
        System.out.print(prompt);
        String s = sc.nextLine();
        return s;
    }
  
   public static String getString(String prompt, String s1, String s2) {
       String s = "";
       System.out.print(prompt);
      
       boolean isValid = false;
       while (!isValid) {
           s = sc.next();
           if(s.equalsIgnoreCase(s1) || s.equalsIgnoreCase(s2)) {
               isValid = true;
           } else {
               System.out.println("Error! This entry is required. Try again.");
           }
           sc.nextLine();          
       }
       return s;
   }

    public static int getInt(String prompt) {
        int i = 0;
        while (true) {
            System.out.print(prompt);
            try {
                i = Integer.parseInt(sc.nextLine());
                break;
            } catch (NumberFormatException e) {
                System.out.println("Error! Invalid integer. Try again.");
            }
        }
        return i;
    }
  
    public static int getInt(Scanner sc, String prompt) {
        int i = 0;
        boolean isValid = false;
        while (!isValid) {
            System.out.print(prompt);
            if (sc.hasNextInt()) {
                i = sc.nextInt();
                isValid = true;
            } else {
                System.out.println("Error! Invalid integer value. Try again.");
            }
            sc.nextLine(); // discard any other data entered on the line
        }
        return i;
    }

    public static int getInt(Scanner sc, String prompt,
            int min, int max) {
        int i = 0;
        boolean isValid = false;
        while (!isValid) {
            i = getInt(sc, prompt);
            if (i <= min) {
                System.out.println(
                        "Error! Number must be greater than " + min + ".");
            } else if (i >= max) {
                System.out.println(
                        "Error! Number must be less than " + max + ".");
            } else {
                isValid = true;
            }
        }
        return i;
    }

    public static double getDouble(String prompt) {
        double d = 0;
        while (true) {
            System.out.print(prompt);
            try {
                d = Double.parseDouble(sc.nextLine());
                break;
            } catch (NumberFormatException e) {
                System.out.println("Error! Invalid decimal. Try again.");
            }
        }
        return d;
    }
  
  
    public static double getDouble(Scanner sc, String prompt) {
        double d = 0.0;
        boolean isValid = false;
        while (!isValid) {
            System.out.print(prompt);
            if (sc.hasNextDouble()) {
                d = sc.nextDouble();
                isValid = true;
            } else {
                System.out.println("Error! Invalid decimal value. Try again.");
            }
            sc.nextLine(); // discard any other data entered on the line
        }
        return d;
    }

    public static double getDouble(Scanner sc, String prompt,
            double min, double max) {
        double d = 0.0;
        boolean isValid = false;
        while (!isValid) {
            d = getDouble(sc, prompt);
            if (d <= min) {
                System.out.println(
                        "Error! Number must be greater than " + min + ".");
            } else if (d >= max) {
                System.out.println(
                        "Error! Number must be less than " + max + ".");
            } else {
                isValid = true;
            }
        }
        return d;
    }

Depositable.java

public interface Depositable {
   void deposit (double amount);
}