Question

I have 2 questions, but they are about the same (similar?) problem.

First question:

public class A {

    public void myProcedure() {
        doSomethingA();
    }

    private void doSomethingA() {}

}

public class B extends A {

    @Override
    public void myProcedure() {
        doSomethingB();
        // IT DOESN'T CALL super.myProcedure
    }

    private void doSomethingB() {}

}

public class C extends B {

    @Override
    public void myProcedure() {
        // I need to execute A's myProcedure here
    }

}

How to run A‘s myProcedure, without setting doSomethingA to public?

Second question:

I create my own TextBox, there is a variable named myValue. Now I create an AdvancedTextBox that inherits TextBox, and AdvancedTextBox need to access myValue variable. The problem is, I want future developer using both TextBox and AdvancedTextBox, or inherit them can’t access myValue. Is it possible?

EDIT: Oli Charlesworth and NullUserException ఠ_ఠ tell me to let C inherit A directly (first question). However, there’s some cases this can be disaster. For example: A = TextBox, B = AdvancedTextBox, C = NumberAdvancedTextBox, if C inherits A, so C have to do everything that B does again, with some small changes.

Answer 1

How about this …

• Put A and C in the same package, and then put B in a different package.
• Remove “private” from A.doSomethingA()
• Give C an instance of A. ( Favor Composition Over Inheritance )
• Since C and A are in the same package, C can call A.doSomethingA() anytime.

Here is definition of A

package ac; 

public class A {

    public void myProcedure() {
        doSomethingA();
    }

   void doSomethingA() {}

}

Here is definition of B

package b;

public class B extends A {

    @Override
    public void myProcedure() {
        doSomethingB();
        // IT DOESN'T CALL super.myProcedure
    }

    private void doSomethingB() {}

}

Here is definition of C

package ac;
// do you really need to extend B? 
public class C {
    A a = new A();

    public void myProcedure() {
        a.doSomethingA(); 
    }

}