Bank-App

A minimalistic banking system with features such as:

• Split transaction
• Online Payment
• Transfer
• Savings account

Design Patterns

1. DAO (https://www.geeksforgeeks.org/data-access-object-pattern/)

• Used DAO for managing a "database" for accounts and users.

2. Command Design Pattern

• Implemented the Command design pattern to handle and execute each user command based on input.

3. Factory Design Pattern

• Used the Command design pattern in the getCommand method, which takes an enum of commands and constructs the appropriate command using a switch statement.

4. Strategy Design Pattern

• Implemented the Strategy Design Pattern for creating each type of cashback.

Project Structure

• The project is structured into 9 packages:

1. bank:

   • Contains the Account class and its subclasses (ClassicAccount and SavingsAccount).
   • Contains the Transaction class and its subclasses, which represent every type of transaction.
     (AccountCreation, CardCreation, CardDestruction, CardPayment,
     DeleteError, FrozenPayment, InsufficientFunds, InterestChanged,
     SendReceive, SplitPaymentTransaction)
   • Contains the User class.
   • Contains the Dao interface, implemented by DaoImpl class.
   • Contains DaoObject, implemented by Account and User classes.
   • Contains Card class and its subclass OneTimeCard.

2. graph:

   • Contains Node class, which represents a node in the currency graph.
   • Contains CurrencyGraph class, implemented to handle currency exchanges

3. command:

   • Contains Client class, implemented for Command Design Pattern.
   • Contains Inovker class of a Command Design Pattern.
   • Contains CommandType enum that lists
     all the commands of the banking system.
   • Contains Command interface, with a specific class for each command.
     (AddAccount, AddFunds, AddInterest, ChangeInterestRate,
     CheckCardStatus, CreateCard, CreateOneTimeCard, DeleteAccount, DeleteCard, PayOnline, PrintTransactions, PrintUsers,
     Report, SendMoney, SetAlias, SetMinimumBalance,
     SpendingsReport, SplitPayment)

4. start:

   • Contains a utility class, with a method that starts the application.

5. main:

   • Contains the main method

6. utils:

   • Contains a utility class that generates IBANs and card numbers.

7. fileio:

   • Contains input classes for handling commands.

8. checker:

   • Contains checker's classes.

9. commerciants:

   • Contains Cashback Strategy classes.
   • Contains Merchant class.

Commands

1. printUsers - Prints a list of all users in the system, along with their details.

2. printTransactions - Prints all transactions of a user.

3. addAccount - adds a new account to a user.

4. addFunds - adds funds to an account.

5. createCard - creates a new card for a user's account.

6. createOneTimeCard - generates a new one-time card for a user's account.

7. deleteCard - deletes a card from an account.

8. deleteAccount - removes an account of the selected user.

9. payOnline - pays an amount to a merchant using a card.

10. setMinimumBalance - sets a minimum balance to an account.

11. checkCardStatus - checks the balance of an account and sets the status of the selected card.

12. sendMoney - transfers an amount of money from a sender account to a receiver account.

13. setAlias - sets a global alias to an account.

14. splitPayment - splits a payment into multiple accounts.

15. addInterest - collects interest for a savings account.

16. changeInterestRate - changes the interest rate for a savings account.

17. report - prints all transactions of an *account.

18. spendingsReport - prints all card payments of a classic account.

19. upgradePlan - changes a user's current account plan to a higher-tier subscription.

"*" - Prints all transactions for a classic account, and only interest rate transactions for a savings account.

Disclaimer

- This is not the final version of the banking system, so many tests may not pass.