Question

Here’s the deal:
I have two objects of different classes, a DataSizeAction and a DataColorAction. The classes have a common ancestor EncoderAction not far up the chain.

Both these objects expose a method called setScale(int scale) which sets a scale type for the encoding they carry out. The method does the same thing in both cases.

However, the method is not present in any common ancestor (btw, this OO is a Library I’m using and the design is not up to my discretion).

I would like to write a method that takes either a DataSizeAction or DataColorAction and calls setScale on that object.

My question is: before I go brute-forcing the separate cases with instanceof, is there a more elegant way to handle this?

Thanks!

Answer 1

Can you add interfaces to your hierarchy?

interface IScalable {
   void setScale(int scale);
   int getScale();
}

class DataSizeAction extends EncoderAction implements IScalable {
   ...
}

class SomeoneElse {
   private int scale = 2;

   public void setScale(IScalable scalable) {
      scalable.setScale(this.scale);
   }
}