How to force classes to use a statement from an abstract method

Question

I have an abstract method that implemented by other classes:

protected abstract void uninstallApp(); 

What I want to do is to force all the classes that must implement this method to use System.out.println() and another method: Log.report()

Is there any way that I can achieve this?

Answer 1

You could for example, do your logging stuff in the parent abstract class in a final method (so the child will not overwrite it). This class call a second method that the child classes should overwrite. Something like following:

protected final void uninstallApp(){
    doUninstallApp();
    Log.report();
}

protected abstract void doUninstallApp();

Answer 2

I agree with @Loic, we can go here for Command pattern...I tried to write the code below..May be It can help..

class Parent {
    public final void uninstallApp() {
        print();
        doSomethingUsefull();
        logReport();
    }

    //To be overriden as per requirement
    protected void logReport() {
        Log.report();
    }

    //To be overriden as per requirement
    protected void print() {
        System.out.println();
    }

    //To be overriden as per requirement
    protected void doSomethingUsefull() {
        //Implementation goes here
    }
}

class Child extends Parent {
    public void logReport() {
        //Implementation goes here
    }

    public  void print() {
       //Implementation goes here
    }

    public void doSomethingUsefull() {
        //Implementation goes here
    }
}

class Main {
    public static void main(String[] args) {
        Parent p = new Child();
        p.uninstallApp();
    }
}