CODEWITHSUNDEEP
oopaggregationcomposition
chitu fds
chitu fds

Reputation: 97

Composition vs Aggregation

Let us say I have a car class and paint class(which consists of different colors). Now In terms of Object oriented design what can be the relation between these two classes is it composition or aggregation. First I thought it would be composition and then I thought it would be aggregation since even if car class is destroyed paint can exist independently. Am I thinking right over here?

Upvotes: 2

Views: 1409

Answers (3)

user5680468
user5680468

Reputation:

It depends on the circumstance, it would be aggregation IMO as there is no strong relationship between a car and its paint, if the paint is removed it does not actually affects the functioning of the car,

But if you think of a relationship between car and engine and if you remove the engine the car cannot move. So this will be composition.

Upvotes: 0

SomeWittyUsername
SomeWittyUsername

Reputation: 18338

Your example is a bit awkward but the question you're asking is exactly what you must answer in order to have the answer. No one but you can answer what is correct for your system.

For example, it will be composition if you're actually talking about an applied paint since it can't reuse/reapply/have paint without a recipient (e.g., a car). It should also be a composition if in your system there is no use for independent paint object.

On the other hand, if a paint is a spray container, it can very much exist without the car concept and can be applied to different cars.

Upvotes: 0

eriknelson
eriknelson

Reputation: 839

I would say it depends on the context of your model. What does your Paint class specifically represent? Is it "a paint job specific to that car"? If so, it is part-of that car and would be considered composition. If it is paint as an independent concept, and an instance can be applied to multiple cars, then a car has-a Paint instance, and it would be considered aggregation.

Upvotes: 1

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