Are there any side effect of using to many static function?

Question

Currently i`m interesting in play framework because this framework promise faster development.

When i see the code, there are so many static code. even the controller declared as static function. Thus all the code that called inside static function must be static right?

My question is, is this approach is right? are there any side effect of using to many static function?

Answer 1

This question has been asked in a similar way previously. The simple answer is that Play uses statics where it is sensible.

The HTTP model is not an OO model. HTTP requests themselves are stateless, and therefore, static methods allow access to controllers as functional requests from client code.

The Model classes on the other hand are pure OO, and as a result are not static heavy. Some of the utility methods, such as findAll or findById are static, but these again are not statefull, and are utility methods on the class. I would expect this in a standard OO model anyway.

Therefore, I don't think there is any risk in doing things in the way Play expects. It may look odd, because it challenges the norm, but it does so for sound reasons.

Answer 2

Couple of things about static methods in an object oriented language: Let me try to explain the problems if you choose to have all static methods.

Using all static functions may not be idiomatic in an Object oriented language. You cannot override static functions in a subclass. Therefore you lose the ability to do runtime polymorphism by overriding.

The variables that you define all become class variables automatically (since all your methods are static), so essentially you do not have any state associated with the instance.

Static methods are difficult to Mock. You might need frameworks like PowerMock to do the mocking for you. So testing becomes difficult.

Design becomes a bit complex as you won't be able to create immutable classes as you really only have the class and no instance. So designing thread-safe classes becomes difficult.

Answer 3

To elaborate on my comment.

static methods can call non-static methods provided you have an instance of something.

class A {
   public void nonStaticMethod() { }

   public static void staticMethod(String text) {
      // calls non-static method on text
      text.length();
      // calls non-static method on new Object
      new Object().hashCode();
      // calls non static method on a instance of A
      new A().nonStaticMethod();
   }
}