Requirements

Determine the different ways the system will be used. This includes main functions the system needs to perform and who will use it.

• Bank class should have
  • Bank accounts for each customer
• Create a unique bank account class for customer
• Bank account should have functions
  • money credited
  • money debited
  • loan policy
  • credit card offers
  • handle authentication
  • account management
    • password change
    • remove credit card
    • add credit card
  • If password incorrect three times, block account for 24 hrs to prevent fraud

Core Objects & Relationships

Based on the requirements and use cases, identify the main objects of the system and analyze how they interact and relate to each other...

Bank account creation follows Factory creation method

• we will use interface and implement interface in class for money credited and debited
  • interface for AccountOperations
    • debit
    • credit
  • abstract class for BankAccount implements AccountOperations
    • protected double balance
    • LoanPolicy
    • CreditCardoffer
    • AccountState
    • BankAccount constrcutor
      • ActiveState
    • authenticate
      • AccountState.authenticate
    • blockAccount
      • return BlockState()
    • executeCommand(AccountCommand command)
      • command.execute()
• with savings and current account form following open closed principle
  • class SavingAccount extends BankAccount
    • constructor()
      • LoanPolicy = new SavingLoanPolicy()
      • CreditCardoffer = new SavingsCreditCardoffer()
    • credit
    • debit
      • if balance is present, then only you can debit
  • class CurrentAccount extends BankAccount
    • constructor()
      • LoanPolicy = new CurrentLoanPolicy()
      • CreditCardoffer = new CurrentCreditCardoffer()
    • credit
    • debit
      • if balance is null, still you can debit
  • interface AccountFactory
    • create
  • class SavingAccountFactory extends AccountFactory
    • create
      • return new SavingAccount();
  • class CurrentAccountFactory extends AccountFactory
    • create
      • return new CurrentAccount();
  • interface LoanPolicy
    • double interestRate()
  • SavingLoanPolicy extends LoanPolicy(class can extend class)
    • interestRate
      • return 8.5
  • CurrentLoanPolicy extends LoanPolicy
    • interestRate
      • return 7.5
  • interface CreditCardoffer
    • String offer
  • SavingsCreditCardoffer extends CreditCardoffer
    • offer
  • CurrentCreditCardoffer extends CreditCardoffer
    • offer
  • interface AccountState
    • authenticate(password)
  • class ActiveState implements AccountState
    • ActiveState constructor(BankAccount account)
      • this.account = account
    • authenticate(password)
      • if password mismatch three times, call blockAccount()
      • else active
  • class BlockState implements AccountState
    • ActiveState constructor(BankAccount account)
      • this.account = account
    • authenticate(password)
      • return RunTimeException timeout for 24 hrs to prevent fraud
  • interface AccountCommand
    • execute()
  • class ChangePassWord implements AccountCommand
    • execute()
  • class AddCreditCard implements AccountCommand
    • execute()
  • class RemoveCreditCard implements AccountCommand
    • execute()
  • Main Class
    • Call AccountFactory for SavingAccountFactory or CurrentAccountFactory

APIs & Class Members

For each class, define the attributes (data) it will hold and the methods (functions) that operate on the attributes. Ensure they align with the object's responsibilities and adhere to the principle of encapsulation. Write your code in the code editor below.

Deep Dive

Explain design tradeoffs you considered. Check and explain whether your design adheres to SOLID principles. Explain how your design can handle changes in scale and whether it would be easy to extend with new functionalities. Identify areas for future improvement...

BankAccount- Creation Factory Pattern

LoanPolicy, CreditCardoffer - Behavioural Strategy Pattern

AccountState - Behavioral State Pattern

AccountCommand - Behavioral Command Pattern

AccountFactory - Open/Closed Principle

it would be easy to extend the design because of following design patterns

Areas for improvement

• code for changePassword etc