设计模式学习10 Facade

使用场景：

Provide a unified interface to a set of interfaces in a subsystem. Façade defines a higher-level interface that makes the subsystem easier to use.

Provide a unified interface to a set of interfaces in a subsystem. Façade defines a higher-level interface that makes the subsystem easier to use. 这个模式更多的是从架构的方式来考虑的。使用多个的subsystem向外提供一个同一的接口，客户程序不必因为内部实现而改变。

实现代码：

// Facade pattern -- Structural example using System; namespace DoFactory.GangOfFour.Facade.Structural { /// <summary> /// MainApp startup class for Structural /// Facade Design Pattern. /// </summary> class MainApp { /// <summary> /// Entry point into console application. /// </summary> public static void Main() { Facade facade = new Facade(); facade.MethodA(); facade.MethodB(); // Wait for user Console.ReadKey(); } } /// <summary> /// The 'Subsystem ClassA' class /// </summary> class SubSystemOne { public void MethodOne() { Console.WriteLine(" SubSystemOne Method"); } } /// <summary> /// The 'Subsystem ClassB' class /// </summary> class SubSystemTwo { public void MethodTwo() { Console.WriteLine(" SubSystemTwo Method"); } } /// <summary> /// The 'Subsystem ClassC' class /// </summary> class SubSystemThree { public void MethodThree() { Console.WriteLine(" SubSystemThree Method"); } } /// <summary> /// The 'Subsystem ClassD' class /// </summary> class SubSystemFour { public void MethodFour() { Console.WriteLine(" SubSystemFour Method"); } } /// <summary> /// The 'Facade' class /// </summary> class Facade { private SubSystemOne _one; private SubSystemTwo _two; private SubSystemThree _three; private SubSystemFour _four; public Facade() { _one = new SubSystemOne(); _two = new SubSystemTwo(); _three = new SubSystemThree(); _four = new SubSystemFour(); } public void MethodA() { Console.WriteLine("\nMethodA() ---- "); _one.MethodOne(); _two.MethodTwo(); _four.MethodFour(); } public void MethodB() { Console.WriteLine("\nMethodB() ---- "); _two.MethodTwo(); _three.MethodThree(); } } }