online-stock-brokerage-system.md

Designing an Online Stock Brokerage System

In this blog post, we'll examine the object-oriented design and implementation of an Online Stock Brokerage System using Java.

This system simulates key functionalities of stock trading platforms, enabling users to engage in buying and selling stocks, manage their portfolios, and stay updated with stock prices.

System Requirements

The Stock Brokerage System needs to:

1. User Account Management: Manage user registrations and profiles.
2. Stock Trading: Enable stock buying and selling.
3. Portfolio Management: Allow users to manage their stock holdings.
4. Stock Price Feed: Provide real-time stock price updates.

Core Use Cases

1. Registering and Managing User Accounts
2. Buying and Selling Stocks
3. Managing Portfolio
4. Viewing Stock Prices

UML/Class Diagrams

Key Classes:

• StockBrokerageSystem: Manages the entire system.
• User: Represents a system user.
• Stock: Represents a stock in the market.
• Portfolio: Manages a user's stock holdings.
• Trade: Handles stock trade transactions.

Java Implementation

User Class

Manages user account information.

import java.util.UUID;

public class User {
    private String userId;
    private String name;
    private Portfolio portfolio;

    public User(String name) {
        this.userId = UUID.randomUUID().toString();
        this.name = name;
        this.portfolio = new Portfolio();
    }

    public void executeTrade(Stock stock, int quantity, TradeType tradeType, StockBrokerageSystem system) {
        system.executeTrade(new Trade(this, stock, quantity, tradeType));
    }

    // Getters and setters...
}

Stock Class

Represents a stock in the market.

public class Stock {
    private String symbol;
    private double price;

    public Stock(String symbol, double price) {
        this.symbol = symbol;
        this.price = price;
    }

    public void updatePrice(double newPrice) {
        this.price = newPrice;
    }

    // Getters and setters...
}

Portfolio Class

Manages a user's stock holdings.

import java.util.HashMap;
import java.util.Map;

public class Portfolio {
    private Map<Stock, Integer> holdings;

    public Portfolio() {
        this.holdings = new HashMap<>();
    }

    public void addStock(Stock stock, int quantity) {
        holdings.put(stock, holdings.getOrDefault(stock, 0) + quantity);
    }

    public void removeStock(Stock stock, int quantity) {
        int currentQuantity = holdings.getOrDefault(stock, 0);
        if (currentQuantity >= quantity) {
            holdings.put(stock, currentQuantity - quantity);
        }
    }

    // Getters and setters...
}

Trade Class

Represents a stock trade transaction.

public class Trade {
    private User user;
    private Stock stock;
    private int quantity;
    private TradeType tradeType;

    public Trade(User user, Stock stock, int quantity, TradeType tradeType) {
        this.user = user;
        this.stock = stock;
        this.quantity = quantity;
        this.tradeType = tradeType;
    }

    // Getters and setters...
}

enum TradeType {
    BUY, SELL
}

StockBrokerageSystem Class

Main class managing the brokerage system.

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

public class StockBrokerageSystem {
    private List<User> users;
    private List<Stock> stocks;

    public StockBrokerageSystem() {
        this.users = new ArrayList<>();
        this.stocks = new ArrayList<>();
    }

    public void executeTrade(Trade trade) {
        if (trade.getTradeType() == TradeType.BUY) {
            processBuyTrade(trade);
        } else if (trade.getTradeType() == TradeType.SELL) {
            processSellTrade(trade);
        }
    }

    private void processBuyTrade(Trade trade) {
        // Logic to process a buy trade
        trade.getUser().getPortfolio().addStock(trade.getStock(), trade.getQuantity());
    }

    private void processSellTrade(Trade trade) {
        // Logic to process a sell trade
        trade.getUser().getPortfolio().removeStock(trade.getStock(), trade.getQuantity());
    }

    // Other necessary methods...
}