门面设计模式和紧密耦合(Facade design pattern and close coupling)

 在学习Facade设计模式时，无处不在我找到这样的例子： 
 
public class SystemA
{
 public void CreateCreditCard(){//implementation}
 //other methods here
}

public class SystemB
{
 public void CheckCreditCard(){//implementation}
//other methods here
}

public class Facade
{
 SystemA subsystemA = new SystemA();
 SystemB subsystemB = new SystemB();

 public void CreateAccount()
 {
   subsystemA.CreateCreditCard();
   subsystemB.CheckCreditCard();
 }
}
 
 我不知道我是否错了，但它不会在Facade类和Systems（SystemA和SystemB）之间创建紧密耦合，即使SystemA和SystemB是从某个抽象类或接口继承的。 

When learning Facade design pattern, everywhere I find this kind of examples:
 
public class SystemA
{
 public void CreateCreditCard(){//implementation}
 //other methods here
}

public class SystemB
{
 public void CheckCreditCard(){//implementation}
//other methods here
}

public class Facade
{
 SystemA subsystemA = new SystemA();
 SystemB subsystemB = new SystemB();

 public void CreateAccount()
 {
   subsystemA.CreateCreditCard();
   subsystemB.CheckCreditCard();
 }
}
 
I don't know if I'm wrong but doesn't it create close coupling between the Facade class and the Systems(SystemA and SystemB), even if SystemA and SystemB are inherited from some abstract class or interface.

原文：https://stackoverflow.com/questions/43110218