food-delivery-service.md

Designing an Online Food Delivery Service Like Swiggy

In this article, we explore the object-oriented design and implementation of an Online Food Delivery Service similar to Swiggy using Java.

This system encompasses functionalities essential for online food ordering and delivery.

System Requirements

The Online Food Delivery System should:

1. Restaurant Management: Manage restaurant profiles, menus, and availability.
2. User Account Management: Handle customer and delivery agent profiles.
3. Order Processing: Enable customers to place orders and track their status.
4. Delivery Management: Assign orders to delivery agents and manage the delivery process.
5. Payment Processing: Handle various modes of payment.

Core Use Cases

1. Adding and Managing Restaurants
2. Registering and Managing User and Delivery Agent Accounts
3. Placing and Tracking Orders
4. Assigning and Managing Deliveries
5. Processing Payments

UML/Class Diagrams

Key Classes:

• OnlineFoodDeliveryService: Manages the overall system.
• User: Represents a customer.
• Restaurant: Manages a restaurant's profile and menu.
• Order: Represents a food order.
• DeliveryAgent: Manages a delivery agent's information.
• Payment: Handles payment transactions.

Java Implementation

Restaurant Class

Manages restaurant information and menus.

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

public class Restaurant {
    private String restaurantId;
    private String name;
    private Map<String, Double> menu; // Menu items and prices

    public Restaurant(String restaurantId, String name) {
        this.restaurantId = restaurantId;
        this.name = name;
        this.menu = new HashMap<>();
    }

    public void addItemToMenu(String itemName, double price) {
        menu.put(itemName, price);
    }

    // Getters and setters...
}

User Class

Manages customer account information.

public class User {
    private String userId;
    private String name;
    private String address;

    public User(String userId, String name, String address) {
        this.userId = userId;
        this.name = name;
        this.address = address;
    }

    // Getters and setters...
}

Order Class

Represents a customer's food order.

import java.util.Date;
import java.util.Map;

public class Order {
    private String orderId;
    private User user;
    private Restaurant restaurant;
    private Map<String, Integer> orderedItems; // Item names and quantities
    private Date orderTime;
    private OrderStatus status;

    public Order(String orderId, User user, Restaurant restaurant, Map<String, Integer> orderedItems, Date orderTime) {
        this.orderId = orderId;
        this.user = user;
        this.restaurant = restaurant;
        this.orderedItems = orderedItems;
        this.orderTime = orderTime;
        this.status = OrderStatus.PLACED;
    }

    public void updateStatus(OrderStatus newStatus) {
        this.status = newStatus;
    }

    // Getters and setters...
}

enum OrderStatus {
    PLACED, PREPARING, OUT_FOR_DELIVERY, DELIVERED, CANCELLED
}

DeliveryAgent Class

Manages delivery agent information.

public class DeliveryAgent {
    private String agentId;
    private String name;
    private boolean isAvailable;

    public DeliveryAgent(String agentId, String name) {
        this.agentId = agentId;
        this.name = name;
        this.isAvailable = true;
    }

    public void setAvailability(boolean isAvailable) {
        this.isAvailable = isAvailable;
    }

    // Getters and setters...
}

Payment Class

Handles payment transactions.

public class Payment {
    private String paymentId;
    private double amount;
    private PaymentStatus status;

    public Payment(String paymentId, double amount) {
        this.paymentId = paymentId;
        this.amount = amount;
        this.status = PaymentStatus.PENDING;
    }

    public void completePayment() {
        this.status = PaymentStatus.COMPLETED;
    }

    // Getters and setters...
}

enum PaymentStatus {
    PENDING, COMPLETED, FAILED
}

OnlineFoodDeliveryService Class

Manages the online food delivery service operations.

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

public class OnlineFoodDeliveryService {
    private List<User> users;
    private List<Restaurant> restaurants;
    private List<Order> orders;
    private List<DeliveryAgent> deliveryAgents;

    public OnlineFoodDeliveryService() {
        this.users = new ArrayList<>();
        this.restaurants = new ArrayList<>();
        this.orders = new ArrayList<>();
        this.deliveryAgents = new ArrayList<>();
    }

    public void addUser(User user) {
        users.add(user);
    }

    public void addRestaurant(Restaurant restaurant) {
        restaurants.add(restaurant);
    }

    public void addOrder(Order order) {
        orders.add(order);
    }

    public void assignDeliveryAgent(String orderId, String agentId) {
        Order order = findOrderById(orderId);
        DeliveryAgent agent = findAgentById(agentId);

        if (order != null && agent != null && agent.isAvailable()) {
            // Assign order to agent and update status
            agent.setAvailability(false);
            order.updateStatus(OrderStatus.OUT_FOR_DELIVERY);
        }
    }

    private Order findOrderById(String orderId) {
        for (Order order : orders) {
            if (order.getOrderId().equals(orderId)) {
                return order;
            }
        }
        return null;
    }

    private DeliveryAgent findAgentById(String agentId) {
        for (DeliveryAgent agent : deliveryAgents) {
            if (agent.getAgentId().equals(agentId)) {
                return agent;
            }
        }
        return null;
    }

    // Other necessary methods...
}