Design Pattern - Structural - Composite

   

Scenario:

Create a Product which could be individually sold or as a bundle.

Solution:

This pattern composes the objects into tree structures to represent part-whole hierarchies.

Example: Product which can be created singularly or as a composite (bundle).

1. Product




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using System.Text;

namespace TestProject
{
    public abstract class Product
    {
        public string Name { get; set; }
        public int Price { get; set; }

        protected Product(string name, int price)
        {
            Name = name;
            Price = price;
        }

        public abstract void Add(Product product);
        public abstract void Delete(Product product);
        public abstract string GetProductDetails();
    }

    public class BundleSku : Product
    {
        private readonly List<Product> _skus = new();

        public BundleSku(string name, int price) : base(name, price)
        {
        }

        public override void Add(Product product)
        {
            _skus.Add(product);
        }

        public override void Delete(Product product)
        {
            _skus.Remove(product);
        }

        public override string GetProductDetails()
        {
            var details = new StringBuilder();
            for (var i = 0; i < _skus.Count; i++)
            {
                details.Append(_skus[i].GetProductDetails());

                details.Append(_skus.Count != i + 1 ? " and " : ".");

                details.Append("\n");
            }
            return details.ToString();
        }
    }

    public class Sku : Product
    {
        public Sku(string name, int price) : base(name, price)
        {
        }

        public override void Add(Product product)
        {
            throw new NotImplementedException();
        }

        public override void Delete(Product product)
        {
            throw new NotImplementedException();
        }

        public override string GetProductDetails()
        {
            return $"{Name} @ ${Price}";
        }
    }
}



2. Create skus and then add them to bundle.

1 2 3 4 5 6 7 8 9 10 11 12 var sku1 = new Sku("IPhone 14", 10000); var sku2 = new Sku("Screen Guard", 200); var sku3 = new Sku("Case", 1000); var bundleSku = new BundleSku("Iphone 14 bundle", 11200); bundleSku.Add(sku1); bundleSku.Add(sku2); bundleSku.Add(sku3); Console.WriteLine($"{bundleSku.Name} comes with: " + $"{bundleSku.GetProductDetails()}The total price of bundle is: ${bundleSku.Price}."); Console.ReadLine();