類設計 - 界面還是抽象類？

我們可以使用多種支付系統（PS1，PS2，PS3 ...）進行支付。常用功能是 - ProcessPayment。該付款基於數據庫中的數據。

我可以使用什麼設計？

1）使用ProcessPayment方法和PaymentSystemBase基類創建IPaymentSystem接口，該類可與數據庫內容（如連接，檢索數據等）一起工作。創建實現IPaymentSystem接口的特定類PS1，PS2，PS3 ...，並從PaymentSystemBase基類派生以使用常見的數據庫內容。

2）創建包含所有ProcessPayment方法和數據庫內容的抽象基類。

3）別的東西。

interface IPaymentSystem 
{ 
    void ProcessPayment(); 
} 

public class PaymentSystemBase 
{ 
    public PaymentSystemBase() 
    { 
     CheckInputParameters(); 
     CreateDatabaseConnection(); 
    } 

    protected void CheckInputParameters() {} 
    protected void CreateDatabaseConnection() {} 
} 

public class PS1 : PaymentSystemBase, IPaymentSystem 
{ 
    public void ProcessPayment() 
    { 
     Console.WriteLine("Process PS1..."); 
    } 
} 

public class PS2 : PaymentSystemBase, IPaymentSystem 
{ 
    public void ProcessPayment() 
    { 
     Console.WriteLine("Process PS2..."); 
    } 
}

來源

2014-03-27 tesicg

你寧願創建一個抽象類爲了把所有的數據庫的東西; 如果你想聲明的接口這是抽象類應該實現它：

// Not necessary 
public IPaymentable { 
    void ProcessPayment(); 
} 

// Interface should be implemented here 
public abstract class PaymentSystemBase: IPaymentable { 
    ... 
    private IDatabaseConnection connectToDatabase() {...} 
    ... 
    protected void loadFromDatabase() {...} 
    protected void saveToDatabase() {...} 
    ... 
    protected PaymentSystemBase() {...} 

    public abstract void ProcessPayment(); 
} 

// A concrete class should only override ProcessPayment() method 
public class PS1: PaymentSystemBase { 
    public override void ProcessPayment() {...} 
} 

// A concrete class should only override ProcessPayment() method 
public class PS2: PaymentSystemBase { 
    public override void ProcessPayment() {...} 
}

來源

2014-03-27 07:50:53