How to reduce the number of variables in the signature of method in child class? Java refactoring-CodePudding

I have an abstract class A which does the main work, and also there are classes B and C which extend class A and implements the method doTheFinalMove().

public abstract class A {

    public Object aMethod() {
        Integer var1 = calculateVar1();
        String var2 = calculateVar2();
        Boolean var3 = calculateVar3();
        Object var4 = calculateVar4();
        Object var5 = calculateVar5();

        return doTheFinalMove(var1,
                var2,
                var3,
                var4,
                var5
        );
    }

    protected abstract Object doTheFinalMove(Integer var1,
                                             String var2,
                                             Boolean var3,
                                             Object var4,
                                             Object var5);

}

public class B extends A {

    @Override
    protected Object doTheFinalMove(Integer var1,
                                    String var2,
                                    Boolean var3,
                                    Object var4,
                                    Object var5) {
        return doMyStaff(
                var1,
                var2,
                var3,
                var4,
                var5);
    }
}

public class C extends A {

    @Override
    protected Object doTheFinalMove(Integer var1,
                                    String var2,
                                    Boolean var3,
                                    Object var4,
                                    Object var5) {
        return doMyStaff(var1, var2);
    }
}

So, class C unlike class B needs only two of the five variables to do its job, but in order to keep the inheritance of the class A, I should use all the five variables in the signature of doTheFinalMove() in A and C classes. I would like to refactor this code in the way that class C keep in its signature only those variables that it really needs (var1 and var2). I want to avoid using Object... args stuff, so I thought about wrapping these variables into an Object(I mean some inheritance like BasicParams and ExtendedParams) and then using an AbstractFactory or smth like that, but I don't know how to do it properly. I would be grateful for any advice.

CodePudding user response：

the simpliest thing it comes to mind is to overload the function:

public Object doTheFinalMove(var1, var2) {
    return doTheFinalMove(var1, null, null, var2, null);
}

Where, instead of null you place the values that are correct for your implementation.

I placed that as public because protected methods are usually ment only for internal use, while public methods are for common use.

Also you cannot directly change the overridden method, because it could be used inside the parent class or in other applications. That's why override works only if you use the exact same format (and possibly behave as intended in the main class).

CodePudding user response：

As suggested you can overload many form of your method in the abstract. You call from the more specific to the less specific in the abstract, then only override the needed method.

public abstract class A {

    public Object aMethod() {
        Integer var1 = calculateVar1();
        String var2 = calculateVar2();
        Boolean var3 = calculateVar3();
        Object var4 = calculateVar4();
        Object var5 = calculateVar5();

        return doTheFinalMove(var1,
                var2,
                var3,
                var4,
                var5
        );
    }    

    protected Object doTheFinalMove(Integer var1,
                                         String var2,
                                         Boolean var3,
                                         Object var4,
                                         Object var5){
         return doTheFinalMove(var1,var2);
    }

    protected abstract Object doTheFinalMove(Integer var1,
                                         String var2);


}


public class B extends A {

    @Override
    protected Object doTheFinalMove(Integer var1,
                                String var2,
                                Boolean var3,
                                Object var4,
                                Object var5) {
    return doMyStaff(
            var1,
            var2,
            var3,
            var4,
            var5);
     }
}

public class C extends A {

    @Override
    protected Object doTheFinalMove(Integer var1,
                                String var2) {
        return doMyStaff(var1, var2);
    }
}