To use self. or not.. in Rails

Question

I\'ve been coding in Ruby for sometime now, but I don\'t understand when to use:

def self.METHOD_NAME
end

or just:

def METH         


        

Answer 1

In this context - def self.method_name makes it sort of equivalent to the Java static method:

ruby:

class HexHelper
  def self.to_h(num)
    sprintf("%x", num)
  end
end

use: HexHelper.to_h(12345)

java:

public class HexHelper
{
  public static String toHex(int num)
  {
    return new PrintfFormat("%x").sprintf(num);
  }
}

use: HexHelper.toHex(12345)