ATM Simulation

import java.util.*;
class Client{
	private int clientId;
	private String name;
	private String nationality;
	private String occupation;
	private String address;
	private int age;
	private String gender;
	private int pin;
	private ArrayList<Account> accounts;
	
	Client(int clientId, String name, String nationality, String occupation, String address, int age, String gender, int pin){
		this.clientId = clientId;
		this.name = name;
		this.nationality = nationality;
		this.occupation = occupation;
		this.address = address;
		this.age = age;
		this.gender = gender;
		this.pin = pin;
		this.accounts = new ArrayList<Account>();
		
	}
	public int getPin() {
		return this.pin;
	}
	public String getName() {
		return this.name;
	}
	public int getClientId() {
		return this.clientId;
	}
	public void addAccount(Account account) {
		this.accounts.add(account);
	}
	public ArrayList<Account> getAccounts(){
		return accounts;
	}
}


abstract class Account{
	private int accountId;
	private static String currency;
	private String branch;
	protected double balance;
	
	Account(int accountId, String currency, String branch){
		this.accountId = accountId;
		this.currency = currency;
		this.branch = branch;
	}
	public int getAccountId() {
		return this.accountId;
	}
	public static String getCurrency() {
		return currency;
	}
	public double getBalance() {
		return this.balance;
	}
	public double deposit(double amount) {
		balance += amount;
		return balance;
	}
	public double withdraw(double amount) {
		if (amount <= this.balance) {
			balance -= amount;
		}
		else {
			System.out.println("Insufficient Balance.");
		}
		return this.balance;
	}
}

class SavingsAccount extends Account{
	double interestRate;
	SavingsAccount(int accountId, String currency, String branch, double interestRate){
		super(accountId, currency, branch);
		this.interestRate = interestRate;
	}
	public double addInterest() {
		balance += (this.interestRate*0.01*this.balance);
		return this.balance;
	}
}

class CurrentAccount extends Account{
	CurrentAccount(int accountId, String currency, String branch){
		super(accountId, currency, branch);
	}
}


class Loan{
	private double amount;
	private double interestRate;
	private double duration;
	private String paymentMethod;
	private Account account;
	
	Loan(double amount, double interestRate, double duration, String paymentMethod, Account account) {
		this.amount = amount;
		this.interestRate = interestRate;
		this.duration = duration;
		this.paymentMethod = paymentMethod;
		this.account = account;
	}
}


class Transaction{
	private int transactionId;
	private int accountId;
	private String date;
	private String status;
	Transaction(int transactionId, int accountId, String date, String status) {
		this.transactionId = transactionId;
		this.accountId = accountId;
		this.date = date;
		this.status = status;
	}
	public int getTransactionId() {
		return transactionId;
	}
	public int getAccountId() {
		return accountId;
	}
	public String getDate() {
		return date;
	}
	public String getStatus() {
		return status;
	}
	
}


class ATM{
	private ArrayList<Client> clients = Bank.getClients();
	ATM(){
		System.out.println("Welcome!");
	}
	public void operateATM() {
		Scanner eye = new Scanner(System.in);
		//requesting client's ID
		System.out.print("Enter Your ClientId: ");
		int clientId = eye.nextInt();
		
		//catch the client with above clientID
		Client user = null;
		for (Client client:clients) {
			if (client.getClientId()==clientId) {
				user = client;
				break;
			}
		}
		
		//Ask PIN number for security verification.
		System.out.print("Enter Your PIN: ");
		int pin = eye.nextInt();
		
		//correct pin number.
		if (user.getPin()==pin) {
			
			//account selection process.
			for (Account account: user.getAccounts()) {
				System.out.println("Account ID: "+account.getAccountId());
			}
			System.out.print("Enter Account ID: ");
			int accID = eye.nextInt();
			Account accountInProcess;
			
			//picking the required account
			for (Account account: user.getAccounts()) {
				if (account.getAccountId()== accID) {
					accountInProcess = account;
					//operation selection.
					System.out.println("1. View Balance.\n"+ "2. Withdraw money.\n"+ "3. Deposit money.\n"+ "4. Exit.");
					System.out.print("Enter your selection: ");
					int option = eye.nextInt();
					if (option == 1) {
						System.out.println("CurrentBalance is: "+accountInProcess.getBalance());
					}
					else if (option==2 || option==3) {
						System.out.print("Enter the amount: ");
						double amount = eye.nextDouble();
						if (option==2) {
							account.withdraw(amount);
							System.out.println("Current Balance is: "+ account.getBalance());
						}
						else {
							account.deposit(amount);
							System.out.println("Current Balance is: "+ account.getBalance());
						}
					}
					else {
						System.out.println("Thank You for Banking With Us.");
						return;
					}
					break;
				}
			}			
		}
		//wrong pin number.
		else {
			System.out.println("Invalid Pin!");
			return;
		}
	}
}


class Bank{
	//this array list can be connected with databases during next level developments.
	private static ArrayList<Client> clients;
	Bank(){
		clients = new ArrayList<>();
	}
	public static ArrayList<Client> getClients() {
		return clients;
	}
	public static void addClients(Client client) {
		clients.add(client);
	}
}



public class ATMTest {
	public static void main(String args[]) {
		//initializing required elements.
		
		//initialize accounts
		SavingsAccount mySavAcc1 = new SavingsAccount(10000, "LKR", "Colombo",7.56);
		CurrentAccount myCurrAcc1 = new CurrentAccount(10001, "LKR", "Colombo");
		
		//initialize client 1
		Client client1 = new Client(1000, "Vinton", "SriLankan", "Computer Scientist", "Colombo", 56, "Male", 129845);
		//adding account details
		client1.addAccount(mySavAcc1);
		client1.addAccount(myCurrAcc1);
		
		//initializing bank accounts for client2
		SavingsAccount mySavAcc2 = new SavingsAccount(10010, "LKR", "Galle",12.45);
		CurrentAccount myCurrAcc2 = new CurrentAccount(10011, "LKR", "Galle");
		
		//initializing client2
		Client client2 = new Client(1001, "Khan", "SriLankan", "Teacher", "Galle", 25, "Male", 129855);
		//adding account details
		client2.addAccount(mySavAcc2);
		client2.addAccount(myCurrAcc2);
		
		//initialize bank objects
		Bank ABC_Bank = new Bank();
		
		//adding clients to the bank
		ABC_Bank.addClients(client1);
		ABC_Bank.addClients(client2);
		
		
		
		//this is the checking step of this code.		
		ATM abcATM = new ATM();
		abcATM.operateATM();
	}
}