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Is extension method a decorator pattern?
5 Answers. A extension method is really just syntactic sugar for calling a static method. While with a decorator you could actually change the behaviour of your decorated class, a extension method could only alter properties or call methods on your class, just like an “ordinary” static method.
How do you use an extension method?
You can use extension methods to extend a class or interface, but not to override them. An extension method with the same name and signature as an interface or class method will never be called. At compile time, extension methods always have lower priority than instance methods defined in the type itself.
What is an advantage of using extension methods?
The main advantage of the extension method is to add new methods in the existing class without using inheritance. You can add new methods in the existing class without modifying the source code of the existing class. It can also work with sealed class.
Are extension methods good?
So if you start using extension functions as a way make Utility classes, then it’s a bad practice. In Java, Utils class are usually a bad practice, not only because of the thread safety but also because they can be a code smell for bad design and because they are hard to test.
When would you use the GOF decorator design pattern?
The decorator pattern can be used to extend (decorate) the functionality of a certain object statically, or in some cases at run-time, independently of other instances of the same class, provided some groundwork is done at design time. This is achieved by designing a new Decorator class that wraps the original class.
Can a decorator be used as an extension?
Extension methods are static beasts defined at compile time and can be used or not… but not modified / exchanged at runtime. Extension methods are not a replacement for the decorator pattern.
Which is the best design pattern for extension?
The best matching design pattern to extension method is Facade pattern. My Reason: We usually use extension methods not to introduce a new functionality beyond the target class responsibility, but simplifying using existing target class usage.
Why do extension methods replace the visitor pattern?
The extension methods can be thought as a replacement of the Visitor Pattern. It is also proposed that they can be used as Adapters. In general languages evolve to make the need of design patterns less necessary. There is a quote for example that Lisp doesn’t need design patterns, because everything is built in the language.
When to use extension methods in C #?
Of course you can use C# extension methods if you want to implement certain design patterns. For example simulate mixins in C#. I wouldn’t label Extension Methods as any of the common design patterns, but it can be used to implement patterns like, Decorator and Adapter etc..