3
votes
3answers
173 views

Understanding UML composition better

The difference between Composition and Aggregation in UML (and sometimes in programming too) is that with Composition, the lifetime of the objects composing the composite (e.g. an engine and a ...
1
vote
3answers
139 views

Does this in the Observer pattern count as composition?

In a classic implementation of the Observer design pattern, the subject has a list of references to all of it's observers, and each observer might have a reference to it's subject. Is this considered ...
4
votes
2answers
234 views

If an entity is composed, is it still a god object?

I am working on a system to configure hardware. Unfortunately, there is tons of variety in the hardware, which means there's a wide variety of capabilities and configurations depending on what ...
3
votes
7answers
902 views

Inheritance using non-abstract base class

This post is based on the question http://stackoverflow.com/questions/49002/prefer-composition-over-inheritance/11758048#comment15634305_11758048. Some people said - check whether there is “is-a” ...
3
votes
1answer
511 views

Composition vs. Inheritance [duplicate]

Here's what is given: public interface Request {} // there are 20 subclasses of Request public class CreateUserRequest implements Request { @NotEmpty public String userName; } // request ...
3
votes
2answers
993 views

OOP - Composition, Components and Composites Example?

I've been reading a bit about OOP in relation to Composition, Components and Composites. I believe I understand the fundamental principle (not sure). Can someone please provide a code example of a ...
0
votes
2answers
460 views

Is this bad design for a Shape interface?

I'm creating a vector editing program in C++, and I need a Shape interface which other concrete classes will implement. There is a requirement that no implementation inheritance is allowed. The design ...
0
votes
2answers
245 views

Inheritance versus Composition in a business application

I have a training management and tracking system, with a high level structure as follows: We have a Role1, e.g. Manager, Shift-boss, miner, etc. and a Candidate, training for that Role. The role has ...
9
votes
5answers
1k views

How do we know to favour composition over generalisation is always the right choice?

Whether an object physically exists or not, we can choose to model it in different ways. We could arbitarily use generalisation or composition in many cases. However, the GoF principle of "favour ...
71
votes
14answers
18k views

Where does this concept of “favor composition over inheritance” come from?

In the last few months, the mantra "favor composition over inheritance" seems to have sprung up out of nowhere and become almost some sort of meme within the programming community. And every time I ...
5
votes
1answer
368 views

Architectural Composition Languages

Recently stumbled upon this paper (PDF) talking about ACLs, or Architectural Composition Languages. They're a fusion of two earlier lines of research: Architectural Definition Languages (such as UML) ...
0
votes
5answers
1k views

Why does the use of interface-based programming appear to be limited to behaviour?

I have been doing a little thinking about inheritance vs. realization vs. composition. I am not about to post the whole detail here. So I was wondering, when we are not talking about creating ...
36
votes
9answers
4k views

Code Smell: Inheritance Abuse [duplicate]

It's been generally accepted in the OO community that one should "favor composition over inheritance". On the other hand, inheritance does provide both polymorphism and a straightforward, terse way of ...