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When to use inheritance instead of composition?
You should use inheritance when subclass “is-a” super class both structurally and functionally, when it can be used as superclass and you are going to use that. If it is not the case – it is not inheritance, but something else. Composition is when your objects consists of another, or has some relationship to them.
When I should use inheritance?
Inheritance should only be used when:
- Both classes are in the same logical domain.
- The subclass is a proper subtype of the superclass.
- The superclass’s implementation is necessary or appropriate for the subclass.
- The enhancements made by the subclass are primarily additive.
What are some alternatives to inheritance?
Delegation can be an alternative to inheritance. Delegation means that you use an object of another class as an instance variable, and forward messages to the instance.
What is the difference between inheritance and composition?
Inheritance essentially provides code reuse by allowing extending properties and behavior of an existing class by a newly defined class. If class A extends B, then class B is called the parent class (or super class) and class A is called the child class (or derived class/sub class).
When to use composition for parent and children?
The point of using composition for the parent/children is that the parent knows about the children but not vice versa. Especially if the relation is more of a ‘contains’ than ‘is composed of’. A reference to the parent is possible and fairly common in C++.
When to use composition over inheritance in Python?
Use composition over inheritance in Python to create components that can be reused by multiple classes in your Python applications. Use composition over inheritance in Python to implement groups of behaviors and policies that can be applied interchangeably to other classes to customize their behavior.
How is inheritance represented in the UML language?
Inheritance models what is called an is a relationship. This means that when you have a Derived class that inherits from a Base class, you created a relationship where Derived is a specialized version of Base. Inheritance is represented using the Unified Modeling Language or UML in the following way: