11

 import java.util.Arrays;
import java.util.List;
import java.util.Map;
import java.util.stream.Collectors;

class Product {
    private int id;
    private String name;
    private double price;
    private String type;
    private double rating;

    public Product(int id, String name, double price, String type, double rating) {
        this.id = id;
        this.name = name;
        this.price = price;
        this.type = type;
        this.rating = rating;
    }

    public double getRating() {
        return rating;
    }

    public double getPrice() {
        return price;
    }

    public String getType() {
        return type;
    }

    @Override
    public String toString() {
        return "Product{" +
                "id=" + id +
                ", name='" + name + '\'' +
                ", price=" + price +
                ", type='" + type + '\'' +
                ", rating=" + rating +
                '}';
    }
}

public class ProductStreamExample {
    public static void main(String[] args) {
        List<Product> products = Arrays.asList(
                new Product(1, "Laptop", 1500.0, "Electronics", 4.5),
                new Product(2, "Smartphone", 800.0, "Electronics", 4.2),
                new Product(3, "Watch", 300.0, "Fashion", 3.8),
                new Product(4, "Headphones", 100.0, "Electronics", 4.8),
                new Product(5, "Shoes", 50.0, "Fashion", 3.5),
                new Product(6, "Camera", 2000.0, "Electronics", 4.7)
        );

        // i) Find all the products having rating between 4 and 5
        List<Product> productsRatingBetween4And5 = products.stream()
                .filter(p -> p.getRating() >= 4 && p.getRating() <= 5)
                .collect(Collectors.toList());
        System.out.println("Products with rating between 4 and 5: " + productsRatingBetween4And5);
		System.out.println();
        
        // ii) Find first n products having price > 10000
        int n = 2;
        List<Product> firstNProductsPriceGreaterThan1000 = products.stream()
                .filter(p -> p.getPrice() > 1000)
                .limit(n)
                .collect(Collectors.toList());
        System.out.println("First " + n + " products with price > 1000: " + firstNProductsPriceGreaterThan1000);
		System.out.println();
        
        // iii) Find the number of products under each type (map containing type and count)
        Map<String, Long> productCountByType = products.stream()
		.collect(Collectors.groupingBy(Product::getType, Collectors.counting()));
        System.out.println("Number of products under each type: " + productCountByType);
		System.out.println();
        
        // iv) Find average rating of products with type = "Electronics"
        double averageRatingElectronics = products.stream()
                .filter(p -> p.getType().equals("Electronics"))
                .mapToDouble(Product::getRating)
                .average()
                .orElse(0.0);
        System.out.println("Average rating of products with type 'Electronics': " + averageRatingElectronics);
    }
}