设计模式示例三　Abstract Factory(抽象工厂)

示例名称:家庭合唱比赛
示例说明:定义抽象的父亲(AbstractFather)、母亲(Abstractmother)和孩子(AbstractChild)及抽象行为Sing。定义抽象的家庭(AbstractFamily)，包含父亲、母亲和孩子行为有初始化成员(ConstructMember),准备(抽象的GetReadyToSing)，合唱(Tutti)，谢幕(抽象的Thank)。定义抽象的家庭工厂负责创建父亲、母亲和孩子。
定义家庭A(FamilyA)、父亲A(FatherA)、母亲A(MotherA)、和孩子A(ChildA)及家庭工厂A(FactoryA)分别继承自家庭、父亲、母亲、孩子和家庭工厂。
示例类图:



关键部分说明

家庭、父亲、母亲、孩子和家庭工厂



//抽象的家庭


abstract class AbstractFamily




...{


//家庭成员


protected AbstractFather farther;


protected Abstractmother mother;


protected AbstractChild child;




//创建家庭成员


public void ConstructMember(AbstractFamilyFactory factory)




...{


farther = factory.CreateFather();


mother = factory.CreateMother();


child = factory.CreateChild();


}




//合唱准备工作


abstract public void GetReadyToSing();


//谢幕


abstract public void Thanks();




//合唱


public void Tutti()




...{


if (farther != null) farther.Sing();


if (mother != null) mother.Sing();


if (child != null) child.Sing();


}


}




//抽象父亲


abstract class AbstractFather




...{


abstract public void Sing();


}




//抽象母亲


abstract class Abstractmother




...{


abstract public void Sing();


}




//抽象孩子


abstract class AbstractChild




...{


abstract public void Sing();


}




//抽象家庭工厂


abstract class AbstractFamilyFactory




...{


abstract public AbstractFather CreateFather();


abstract public Abstractmother CreateMother();


abstract public AbstractChild CreateChild();


}

关键在于这个抽象的家庭(AbstractFamily)，它的行为合唱(Tutti)包装了基于通过抽象的家庭工厂(AbstractFamilyFactory)创建的家庭成员的行为。

家庭A



class FamilyA : AbstractFamily




...{


public FactoryA factory = new FactoryA();




public override void GetReadyToSing()




...{


Console.WriteLine("我们是幸运家庭A,我们已经做好了上台的准备！");


}




public override void Thanks()




...{


Console.WriteLine("我们是幸运家庭A,我们的演出结束，谢谢大家！");


}


}




class FatherA : AbstractFather




...{


public override void Sing()




...{


Console.WriteLine("我是父亲，我唱男高音！");


}


}




class MotherA : Abstractmother




...{


public override void Sing()




...{


Console.WriteLine("我是母亲，我唱民歌");


}


}




class ChildA : AbstractChild




...{


public override void Sing()




...{


Console.WriteLine("我是孩子，我唱儿童歌曲！");


}


}




class FactoryA : AbstractFamilyFactory




...{


public override AbstractFather CreateFather()




...{


return new FatherA();


}


public override Abstractmother CreateMother()




...{


return new MotherA();


}


public override AbstractChild CreateChild()




...{


return new ChildA();


}


}

通过对对应的抽象类的继承实现了和抽象类相同的创建、组织和表示。

调用及运行结果


FamilyA family = new FamilyA();


family.ConstructMember(family.factory);


family.GetReadyToSing();


family.Tutti();


family.Thanks();