如何從字段訪問父級方法？

Question

我有樹類。

class MyObject{ 
    public void DoSomething() 
    { 
     here I need to call method add from class base. 
    } 
} 

class base 
{ 
    protected final void add(){}  
} 

class extended extends base { 
    private MyObject pObject = new MyObject(); 
    ... 
    { 
     pObject.DoSomething(); 
    } 
} 

我可以創建類，擴展類擴展的每個變化，但我需要使用類型變得可用後才類擴展已經啓動。

我如何從撥打base.add() MyObject內在方法？

Answer 1

你可以做到在幾個方面：

• 有在MyObject類的extended類的參考。當您在extended類中實例化MyObject變量時，請將其傳遞給參考extended。

事情是這樣的：

class MyObject{ 
    private base baseObj; 

    public MyObject(base baseObj){ 
     this.baseObj = baseObj; 
    } 

    public void DoSomething() 
    { 
     //here I need to call method add from class base. 
      //use baseObj to call the methods 
    } 
} 


class base 
{ 
    protected final void add(){}  
} 


class extended extends base { 
    private MyObject pObject; 
    ... 

    public extended(){ 
     pObject = new MyObject(this); 
    } 

    { 
     pObject.DoSomething(); 
    } 
} 

• 聲明中staticbase類的方法。這樣您就可以調用這些方法而不需要base類的實例。

事情是這樣的：

class MyObject{ 

    public void DoSomething() 
    { 
     //here I need to call method add from class base. 
     //call like this 
     base.add(); 
    } 
} 


class base 
{ 
    protected static final void add(){}  
} 


class extended extends base { 
    private MyObject pObject; 
    ... 

    public extended(){ 
     pObject = new MyObject(this); 
    } 

    { 
     pObject.DoSomething(); 
    } 
} 

一兩件事：這是題外話，但你可能想閱讀有關Java Naming Conventions。以小寫開頭的類名是在命名約定中找不到的。

Answer 2

虛設這樣的代碼：

class MyObject{ 
    public void DoSomething(Base base) 
    { 
     base.add(); 
    } 
} 

class extended extends base { 
    private MyObject pObject = new MyObject(); 
    ... 
    { 
     pObject.DoSomething(this); 
    } 
}