如何通过调用方法访问主叫对象的成员在JAVA

Question

这里是我的代码

class Base 
{ 
    public void fillRandomData() 
    { 
    //code for accessing members for sub classes 
     //here object "b" is calling this method 
     //I want to access members of caller object 
     //As it is Derived class how can I access its member 
    } 
} 

class Derived extends Base 
{ 
    Map<String, List<Integer>> fields = new HashMap<String,List<Integer>>(); 
    List<Integer> attribute = new ArrayList<Integer>(); 

    public Derived() { 
     attribute.add(1); 
     fields.put("textbox",attribute); 
    } 
} 

class Main 
{ 
    public static void main(String[] argv) { 
     Base b = new Base(); 
     **b.fillRandomData();** 
    } 
} 

上面的代码解释了我的问题。 我在访问调用者对象成员stucked 我认为回顾将有所帮助但它并没有帮助我很多。

在ruby中有方法“instance_variable_get（instance_var）”，它允许访问调用者对象的数据成员。

Answer 1

您必须定义方法并调用您的方法进入您无法在类块中调用方法。

这样的：

class Main 
{ 
void callMethod(){ 
    Base b = new Base(); 
    b.fillRandomData(); 
} 
} 

Answer 2

从我从你的问题了解你想要做的事，如：

class Base 
{ 
    public void fillRandomData() 
    { 
     // do not directly access members. you can use reflect to do this but do not do this. 
     // (unless you have a real reason for it) 
     // 
     // instead, trust on the subclasses to correctly override fillRandomData to fill in the 
    } 
} 

class Derived extends Base 
{ 
    Map<String, List<Integer>> fields = new HashMap<String,List<Integer>>(); 
    List<Integer> attribute = new ArrayList<Integer>(); 

    public Derived() { 
     attribute.add(1); 
     fields.put("textbox",attribute); 
    } 

    @Override 
    public void fillRandomData() { 
     // in Main, the b.fillRandomData will run this method. 

     // let the Base class set it's part of the data 
     super.fillRandomData(); 

     // then let this class set it's data 
     // do stuff with attributes 
     // do stuff with fields. 
    } 
} 

class Main 
{ 
    // you _must_ instantiate a derived object if you want to have a chance at getting it's instance variables 
    public static void main(String[] argv) { 
     Base b = new Derived(); 
     b.fillRandomData(); 
    } 
}