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Posted By

c00lryguy on 07/21/09


Tagged

ruby


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BeforeAndAfter

 / Published in: Ruby
 

Allows you to create before and after methods in a class

Example 
require "before_and_after"

class Message
  include BeforeAndAfter

  def initialize message
    @message = message
  end

  def display
    puts @message
  end

  def before_display
    puts "BEFORE DISPLAY"
  end

  def after_display
    puts "AFTER DISPLAY"
  end

  use_method :display
end

Message.new( "== MESSAGE ==" ).display
Outputs 
BEFORE DISPLAY
== MESSAGE ==
AFTER DISPLAY
before_and_after.rb

 

Expand | Embed | Plain Text 
  1. module BeforeAndAfter
  2.   # This extends the class that includes BeforeAndAfter with the methods in ClassMethods
  3.   def self.included(base)
  4.     base.extend(ClassMethods)
  5.   end
  6.  
  7.   module ClassMethods
  8.     def use_method *methods
  9.       methods.each { |method|
  10.         # Set up the before and after variables
  11.         before_method = "before_#{method.to_s}".to_sym
  12.         after_method = "after_#{method.to_s}".to_sym
  13.         # Unbind the original, before, and after methods
  14.         unbinded_before_method = instance_method( before_method )
  15.         unbinded_method = instance_method( method )
  16.         unbinded_after_method = instance_method( after_method )
  17.         # Define the before and after methods if they don't already exist
  18.         define_method( before_method ) unless self.method_defined?( before_method )
  19.         define_method( after_method ) unless self.method_defined?( after_method )
  20.         # Redefines the method to run the before and after methods
  21.         define_method( method ) {
  22.           unbinded_before_method.bind( self ).call # Bind the unbinded BEFORE method
  23.           unbinded_method.bind( self ).call        # Bind the original method
  24.           unbinded_after_method.bind( self ).call  # Bind the unbinded AFTER method
  25.         }
  26.       }
  27.     end
  28.   end
  29. end

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