Hierarchy inheritance

I had faced the problem. In my C++ hierarchy tree I have two branches for entities of difference nature, but same behavior - same interface. I created such hierarchy trees (first in image below). And now I want to work with Item or Base classes independetly of their nature (first or second). Then I create one abstract branch for this use. My mind build (second in image below). But it not working. Working scheme seems (third in image below). It's bad logic, I think... Do anybody have some ideas about such hierarchy inheritance? How make it more logical? More simple for understanding?

Image

Sorry for my english - russian internet didn't help:)

Update: You ask me to be more explicit, and I will be.

In my project (plugins for Adobe Framemaker) I need to work with dialogs and GUI controls. In some places I working with WinAPI controls, and some other places with FDK (internal Framemaker) controls, but I want to work throw same interface.

I can't use one base class and inherite others from it, because all needed controls - is a hierarchy tree (not one class).

So I have one hierarchy tree for WinAPI controls, one for FDK and one abstract tree to use anyone control.

For example, there is an Edit control (WinEdit and FdkEdit realization), a Button control (WinButton and FdkButton realization) and base entity - Control (WinControl and FdkControl realization).

For now I can link my classes in realization trees (Win and Fdk) with inheritence between each of them (WinControl is base class for WinButton and WinEdit; FdkControl is base class for FdkButton and FdkEdit). And I can link to abstract classes (Control is base class for WinControl and FdkControl; Edit is base class for WinEdit and FdkEdit; Button is base class for WinButton and FdkButton). But I can't link my abstract tree - compiler swears.

In fact I have two hierarchy trees, that I want to inherite from another one.

Update:

I have done this quest! :)

I used the virtual inheritence and get such scheme (http://img12.imageshack.us/img12/7782/99614779.png). Abstract tree has only absolute abstract methods. All inheritence in abstract tree are virtual. Link from realization tree to abstract are virtual. On image shown only one realization tre开发者_StackOverflowe for simplicity.

Thanks for help!

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C++ supports multiple inheritance, so you can have the union of (2) and (3), making sure that AbstractBase is always declared as a virtual base class.

Without knowing the real meaning and purpose of the various classes, it's difficult to offer any better advice.

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It's not clear from the description if this would work for you but typically classes with a common interface would define the interface in AbstractBase and then have concrete instances inherit directly from that (FirstItem, SecondItem).

Why the extra indirection(s) in your examples? What's expected to be in AbstractItem, FirstBase and SecondBase?

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For using different implementations of one interface, on could use: the Bridge Design Pattern

You might couple this with a Factory Design Pattern so as to construct your two implementations differently.

However, it may look too simple for your classes architecture.

But as the comments under your answer say: it is difficult to imagine the job/role of your classes with such names. You should be more explicit, so as we can think of a precise design.