Should I use inheritance or composition?

Question

I would like to keep this one short. I build a HouseA that has two rooms, say `BedRoom` and `StudyRoom`, both deriving from a base class called `Room`. `BedRoom` and `StudyRoom` have a same parent called `House`. Also, any room in a house can access any other rooms only through the parent. If `BedRoom` has to access any attribute of `StudyRoom`, it has to go only via `House` (i.e. parent) and vice-versa. ``` HouseA ISA House HouseA HAS BedRoom and StudyRoom. BedRoom ISA Room StudyRoom ISA Room ``` Now the Problem: Let's say, I build another home (say `HouseB`), which is a exactly the same as the above, but with one change. I don't want two separate rooms (i.e. `BedRoom` and `StudyRoom`), but instead a single room (`MasterRoom`) which has both these facilities. For the sake of code reusability, I could think of the following design options: ``` Option-1: HouseB ISA House HouseB HAS MasterRoom MasterRoom ISA Room ``` Here I lose the ability to reuse the attributes of `BedRoom` and `Stud…

Accepted Answer

Why not use roles to achieve this:

```
House A has a Bedroom
Bedroom does SleepingArea
House has a Studyroom
Studyroom does ComfyArea

House B has a MasterRoom
MasterRoom does SleepingArea and ComfyArea
```

The easiest way to get roles is to use Moose.

Should I use inheritance or composition?

Solution

Problem