模板方法

模板方法

模板方法 是一种行为模式，它允许子类实现可变的行为。在下面的示例中，我们使用模板方法来允许子类实现制作热饮的方式。

模板方法模式的 VB 示例

Public Class MyPage
          Public Sub Page_Load()
     
        Dim CupOfTea As HotDrink
        CupOfTea = New Tea

        Dim CupOfCoffee As HotDrink
        CupOfCoffee = New Coffee

        MakeDrink(CupOfTea)        

        Response.write(".........
")

        MakeDrink(CupOfCoffee)

     End Sub
     ''' 

     ''' Generic Method that will make the hot Drink
     ''' 
     Public Sub MakeDrink(ByVal HotDrink As HotDrink)
      
        HotDrink.boilWater()
        HotDrink.addIngredients()
        HotDrink.addCondiments()
     End SubEnd Class
''' 
''' Abstract Class
''' 
Public MustInherit Class HotDrink

     Public Sub boilWater()
          Response.write("Boiling Water...
")
     End Sub
     Public MustOverride Sub addIngredients()

     Public MustOverride Sub addCondiments()End Class
''' 
''' Tea Class that implements behaviour that can vary i.e.
''' the addIngredients & addCondiments methods
''' 
Public Class Tea
     Inherits HotDrink

     Public Overrides Sub addCondiments()
         Response.write("Add Milk ...
")
     End Sub
     Public Overrides Sub addIngredients()
         Response.write("Add Tea Bags ...
")
     End SubEnd Class
''' 
''' Coffee Class that implements behaviour that can vary i.e.
''' the addIngredients & addCondiments methods
''' 
Public Class Coffee
     Inherits HotDrink

     Public Overrides Sub addCondiments()
         Response.write("Add Milk ...
")
     End Sub
     Public Overrides Sub addIngredients()
         Response.write("Add Coffee Granules ...
")
     End Sub
End Class

UML