Factory Method Pattern Code Review

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Download Description:factory method pattern download
.NET Framework:3.5
.NET Language:C#
Date Published:2009-07-01
Download Size:8 KB

Define the Factory Object

The Factory class (object) defines the FactoryMethod() method, which decides which subclass to instantiated.

class Factory { public Product.IProduct FactoryMethod(Int32 month) { if (month >= 4 && month <=11) { return new Product.ProductA(); } else if (month == 1 || month == 2 || month == 12) { return new Product.ProductB(); } else { return new Product.ProductC(); } } }

Define the Product Interface and Handler Objects

Define the Product class containing the IProduct interface and inherited Product subclasses.

class Product { public interface IProduct { String ShipFrom(); }
internal class ProductA : IProduct { public String ShipFrom() { return (" from South Africa."); } }
internal class ProductB : IProduct { public String ShipFrom() { return (" from Spain."); } }
internal class ProductC : IProduct { public String ShipFrom() { return (" not available."); } } }

Use the Factory Method Pattern

The Program class creates an instance of the Factory class, and creates instance of IProduct interface.

class Program { static void Main(string[] args) { Factory factory = new Factory(); Product.IProduct product;
for (Int32 i = 1; i <= 12; i++) { product = factory.FactoryMethod(i); Console.WriteLine(String.Format("Product {0}", product.ShipFrom())); }
Console.Read(); } }

During the iteration process a specific Product subclass is created by the FactoryMethod() method and relevant ShipFrom() method invoked on the subclass.