CODEWITHSUNDEEP
design-patterns
Benny
Benny

Reputation: 498

Is Delegation Pattern is a basic & crucial pattern? (excluding JAVA)

I've read that Delegation Pattern used to "Simulate multiple inheritance in JAVA". I wonder what about languages like Cpp which allows us 'multiple inhertance', is Delegation Pattern still necessary?

Upvotes: 0

Views: 51

Answers (1)

Matei Florescu
Matei Florescu

Reputation: 1195

I assume that by "Simulate multiple inheritance in JAVA" you mean a class that extends another one and also implements one interface, and has a class variable of a type that also implements that interface, plus the methods that delegate.
For ex. 

class A extends B implements C {
   private C c;

   public void Cmethod {
       c.Cmethod();
   }
...
}

Indeed, in C++ you do not need to do this, since you already have multiple inheritance. But there are a lot of other uses for delegation. For example, handling events in a GUI toolkit can be achieved using delegation: a component (say button) receives a message and delegates its handling to another component. So a delegate is a valid concept in C++.

Upvotes: 1

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