How can I create a class with constructor and functions in R like java or c++?

Question

I want to write R script class like java or c++ programming language. But, I didn't find any example. Here is the main structure of a class in java or c++:

Myclass{

  param1
  param2
  ...

  Constructor(...){
    .
    . 
    .
  }

  function1(...){
    .
    . 
    .
  }

  function2(...){
    .
    . 
    .
  }

  .
  . 
  .
}

Is it possible to create a class like the above? Can anyone show me an example?