BankAccount.java

import java.util.ArrayList;
import java.util.Date;
import java.util.List;

/**
 * Base class for bank accounts.
 */
public class BankAccount {
    // Instance variables with private access modifier (encapsulation)
    private String accountNumber;
    private String pin;
    private double balance;
    private String accountType;
    private List<Transaction> transactionHistory;

    // Constant minimum balance
    public static final double MINIMUM_BALANCE = 100.0;

    // Constructor
    public BankAccount(String accountNumber, String pin, double initialBalance, String accountType) {
        this.accountNumber = accountNumber;
        this.pin = pin;
        this.balance = initialBalance;
        this.accountType = accountType;
        this.transactionHistory = new ArrayList<>();
    }

    // PIN validation
    public boolean validatePin(String enteredPin) {
        return this.pin.equals(enteredPin);
    }

    // Method overloading for deposit
    public boolean deposit(double amount) {
        return deposit(amount, "Regular deposit");
    }

    public boolean deposit(double amount, String description) {
        if (amount <= 0) {
            return false;
        }
        this.balance += amount;
        this.transactionHistory.add(new Transaction(
            "Deposit",
            amount,
            new Date(),
            description
        ));
        return true;
    }

    // Withdrawal with exception handling
    public boolean withdraw(double amount) {
        try {
            if (amount <= 0) {
                throw new IllegalArgumentException("Invalid amount");
            }
            if (amount > this.balance) {
                throw new InsufficientFundsException("Insufficient funds");
            }

            this.balance -= amount;
            this.transactionHistory.add(new Transaction(
                "Withdrawal",
                amount,
                new Date(),
                "ATM withdrawal"
            ));
            return true;

        } catch (Exception e) {
            System.err.println(e.getMessage());
            return false;
        }
    }

    // Getters
    public double getBalance() {
        return balance;
    }

    public String getAccountNumber() {
        return accountNumber;
    }

    public String getAccountType() {
        return accountType;
    }

    public List<Transaction> getTransactionHistory() {
        return new ArrayList<>(transactionHistory); // Return a copy
    }
}