工厂模式

namespace UnitTestProject1.BaseDesign
{

    /// <summary>
    /// 工厂方法模式要求:尽量使用抽象类或接口来定义就可以达到一个开闭原则
    /// </summary>
    [TestClass]
    public class BaseDesign
    {
        [TestMethod]
        public void TestMethod1()
        {
            GetAnimalEat(new DogFactoryFactory());

            GetAnimalEat(new PigFactoryFactory());

            //如果再增加一个AnimalEat不会对现有代码有改动
        }

        void GetAnimalEat(AnimalFactory fa)
        {
            Animal am = fa.GetAnimal();
            am.Eat();
        }
    
    }
    public abstract class Animal
    {
        public abstract void Eat();
    }

    public class Dog : Animal
    {
        public override void Eat()
        {
            Console.WriteLine("dog eat");
        }
    }

    public class Pig : Animal
    {
        public override void Eat()
        {
            Console.WriteLine("pig eat");
        }
    }

    public abstract class AnimalFactory
    {
        public abstract Animal GetAnimal();
    }

    public class DogFactoryFactory : AnimalFactory
    {
        public override Animal GetAnimal()
        {
            return new Dog();
        }

    }
    public class PigFactoryFactory : AnimalFactory
    {
        public override Animal GetAnimal()
        {
            return new Pig();
        }
    }
}