Simplified Banking System

A console-based banking system demonstrating key software design patterns in Java. The application allows creating different types of bank accounts, performing transactions (deposit, withdraw, transfer), and managing account states (activate, deactivate).

Features

• Account Types: Savings, Checking, and Business accounts, each with its own transaction fee rate.

• Create Account: Open new accounts with an initial deposit.

• Deposit & Withdraw: Add or remove funds, with fees applied on withdrawals.

• Transfer: Send money between accounts, deducting transaction fees from the sender.

• View Account: Display balance, state (Active/Inactive), and transaction history.

• Activate/Deactivate: Enable or disable accounts to control operations.

Design Patterns

Pattern	Purpose
Singleton	BankingSystem ensures a single instance manages all accounts.
Proxy	BankingSystemProxy defines the interface for banking operations.
State	AccountState interface handles activate/deactivate behavior.
Template	Abstract Account class provides shared logic for all accounts.

How to Run

1. Clone the Repository

   git clone https://github.com/yourusername/Simplified-Banking-System.git
   cd Simplified-Banking-System

2. Compile and Run

   javac Main.java
   java Main

3. Input Commands

• First line: number of operations n.

• Next n lines: commands in one of the following formats:

  1. Create <AccountType> <AccountName> <InitialDeposit>

  2. Deposit <AccountName> <Amount>

  3. Withdraw <AccountName> <Amount>

  4. Transfer <FromAccount> <ToAccount> <Amount>

  5. View <AccountName>

  6. Deactivate <AccountName>

  7. Activate <AccountName>

Example Session

7
Create Savings Alice 1000.00
Deposit Alice 200.00
Create Checking Bob 500.00
Transfer Alice Bob 150.00
Withdraw Bob 50.00
Deactivate Alice
View Alice

Output:

A new Savings account created for Alice with an initial balance of $1000.000.
Alice successfully deposited $200.000. New Balance: $1200.000.
A new Checking account created for Bob with an initial balance of $500.000.
Alice successfully transferred $147.000 to Bob. New Balance: $1050.000. Transaction Fee: $3.000 (0.015%) in the system.
Bob successfully withdrew $49.000. New Balance: $696.000. Transaction Fee: $1.000 (0.02%) in the system.
Alice's account is now deactivated.
Alice's Account: Type: Savings, Balance: $1050.000, State: Inactive, Transactions: [Initial Deposit $1000.000, Deposit $200.000, Transfer   $150.000].

Project Structure

.
├── Main.java             # Entry point, parses and delegates commands
├── BankingSystemProxy.java  # Interface defining banking operations
├── BankingSystem.java    # Singleton implementation of proxy, manages accounts
├── Account.java          # Abstract base class with common logic
├── AccountState.java     # Interface for activate/deactivate behavior
├── SavingsAccount.java   # Savings account implementation
├── CheckingAccount.java  # Checking account implementation
├── BusinessAccount.java  # Business account implementation
└── DecimalFormatSymbols  # Utility for formatting monetary values