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6
votes
1answer
399 views

Is it fair to say that “macros don't compose”?

On this blog post aphyr (who is a brilliant programmer) states: Clojure macros come with some important restrictions. Because they’re expanded prior to evaluation, macros are invisible to ...
4
votes
1answer
695 views

Inheritance in test classes

I have an interface Serializer with methods serialize and isSerializerFor. I created a first implementation of this using TDD, and ended up with a nice clean test case fully covering a nice clean ...
4
votes
2answers
317 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 ...
4
votes
2answers
278 views

Is excessive indirection and/or redundant encapsulation a recognized concept? [closed]

I'm curious if there's a series of tendencies or anti-patterns when programming whereby a developer will always locally re-wrap external dependencies when consuming them. A slightly less vague ...
1
vote
1answer
556 views

Internal exposure of implementation details on inheritance

I'm reading the "Effective Java" book which suggests to favor composition over inheritance. The example it gives shows something like this: public class InstrumentedHashSet<E> extends HashSet&...
8
votes
2answers
1k views

How do I avoid writing lots of pass-through functions in a wrapper?

I have a class, which wraps another class of a common base type. Because the base type interface is quite large this involves writing a lot of pass-through functions. I am looking for a way to avoid ...
6
votes
3answers
1k views

Looking for a real-world example illustrating that composition can be superior to inheritance [closed]

I watched a bunch of lectures on Clojure and functional programming by Rich Hickey as well as some of the SICP lectures, and I am sold on many concepts of functional programming. I incorporated some ...
3
votes
3answers
3k views

what does composition example vs aggregation

Composition and aggregation both are confusion to me. Does my code sample below indicate composition or aggregation? class A { public static function getData($id) { //something } ...
2
votes
5answers
2k views

How do inheritance and composition differ?

I'm wondering about the differences between inheritance and composition examined with concrete code relevant arguments. In particular my example was: Inheritance: class Do: def do(self): ...
3
votes
7answers
2k 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” ...
4
votes
1answer
302 views

Is this Hybrid of Interface / Composition kosher?

I'm working on a project in which I'm considering using a hybrid of interfaces and composition as a single thing. What I mean by this is having a contain*ee* class be used as a front for ...
12
votes
2answers
3k views

When Rob Pike says “Go is about composition”, what exactly does he mean? [closed]

From Less is Exponentially More If C++ and Java are about type hierarchies and the taxonomy of types, Go is about composition.
4
votes
1answer
716 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 ...
7
votes
4answers
2k views

Is dependency injection by hand a better alternative to composition and polymorphism?

First, I'm an entry level programmer; In fact, I'm finishing an A.S. degree with a final capstone project over the summer. In my new job, when there isn't some project for me to do (they're waiting ...
4
votes
6answers
2k views

What are the alternatives to “overriding a method” when using composition instead of inheritance?

If we should favor composition over inheritance, the data part of it is clear, at least for me. What I don't have a clear solution to is how overwriting methods, or simply implementing them if they ...
4
votes
2answers
2k 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 ...
1
vote
2answers
626 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 ...
56
votes
4answers
32k views

Why should I prefer composition over inheritance?

I always read that composition is to be preferred over inheritance. A blog post on unlike minds, for example, advocates using composition over inheritance, but I can't see how polymorphism is achieved....
0
votes
2answers
301 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 ...
4
votes
1answer
723 views

Model independency in MVC and most efficient way to do method calls

TLDR: Are models supposed to be application-dependant and totally worthless when starting a new application, or are you supposed to design models independently so that they act as stand-alone classes/...
6
votes
3answers
252 views

How to design a system that allows for multiple parallel extensions of the same “component”?

As a player, I found the following problems about creating and using "extensions" (aka mods) for games: 1) Whenever the game is updated, all the mods break. 2) Most mods don't work with each ...
5
votes
2answers
610 views

Is it possible to refactor inheritance to composition when virtual methods are called inside the base class?

Let's say I have a class called Country and two subclasses called AI and Player. The Country class has a number of virtual methods to allow player-specific or AI-specific behavior. I want to make it ...
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 ...
107
votes
14answers
29k 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 ...
2
votes
4answers
444 views

“Imprinting” as a language feature?

Idea I had this idea for a language feature that I think would be useful, does anyone know of a language that implements something like this? The idea is that besides inheritance a class can also ...
5
votes
1answer
512 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) ...
1
vote
5answers
2k 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 ...
12
votes
9answers
2k views

Should a developer know the inner workings of the computers' hardware? [closed]

I'm not talking just how memory is assigned and memory management (things that you can learn from C for example) but rather the hardware aspect and how each component of the computer hardware works ...
46
votes
9answers
8k 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 ...