在对象B中，如何访问已创建对象B的对象A？

Question

My code is of the form below:

public class Outer {

    protected int data;
    protected Inner inner;

    protected void run() {
        inner = new Inner();
    }

}

public class Inner extends Outer {

    protected getOuterData() {
        ...
    }
}

An Inner object will only be created within a method of class Outer . Within an Inner object, is there a way to access the data of an instance of class Outer that has created the Inner object?

EDIT: I realise that you can just pass the outer object into the inner object via a constructor but I was wondering if there was another way?

EDIT2: Actually passing the object via the constructor will be OK for what I'm doing.

Answer 1

public class Outer {

    protected int data;
    protected Inner inner;

    protected void run() {
        inner = new Inner(this);
    }

}

public class Inner extends Outer {
    private Outer parent;
    Inner(Outer parent) {
        this.parent = parent
    }

    protected getOuterData() {
        return parent;
    }
}

Answer 2

May be this will help you.

public class Outer {

    protected int data;
    protected Inner inner;

    protected void run() {
        inner = new Inner();
    }

}

public class Inner extends Outer {

    protected void getOuterData() {
        Outer out = new Outer();        // Create instance of `Outer`
        out.run();                      // Create instane of `Inner`
        Inner inner = out.inner;        // Access data from Outer instance
        int data = out.data;            // Access data from Outer instance
    }
}

Answer 3

public class Outer {

protected int data;
protected Inner inner;

protected void run() {
    inner = new Inner();
}

}

public class Inner extends Outer {

protected getOuterData() {
    ...
  int localData = data;\\if not already defined with same name
  int localData = super.data;\\if already defined with same name in Inner
}

}

PS: I think you are doing something wrong by creating Child class object in parent class method. it may go in infinite loop for creating objects when you initialise child, it will create parent object, which intern create child and so on.

To avoid this make sure not to use run in constructor.