Module: Callbacks
- Defined in:
- lib/ruby-callbacks.rb
Overview
module Callbackable allows to add callbacks before and after methods
Example
require "ruby-callbacks"
class Cat
include Callbacks
attr_accessor :name, :colour
callback :after, :eat, :play
callback :before, :eat, :sleep
def initialize(name, colour)
@name = name
@colour = colour
end
def sleep
puts "#{@name} the cat is sleeping"
end
def eat
puts "#{@name} the cat is eating"
end
def play
puts "#{@name} the cat is playing"
end
end
kitty = Cat.new("Kitty", "black")
kitty.eat
# => Kitty the cat is sleeping
# => Kitty the cat is eating
# => Kitty the cat is playing
Defined Under Namespace
Classes: UnknownEventException
Constant Summary collapse
- SALT =
md5 for word “method”
"ea9f6aca279138c58f705c8d4cb4b8ce"
Class Method Summary collapse
Class Method Details
.included(base) ⇒ Object
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# File 'lib/ruby-callbacks.rb', line 49 def self.included(base) base.class_eval do @@_method_chain = Hash.new @@_callbacks_running = Array.new # show current_method_chain def self.method_chain @@_method_chain end # allows to add a callback to already initialized class # == Example # class Cat # include Callbacks # # def purr # # purr # end # # def sleep # # sleep # end # end # # Cat.add_callback(:after, :purr, :sleep) # Cat.new.purr # purr, then sleep def self.add_callback(event, method, callback) if callbacks_exist? method callback(event, method, callback) else callback(event, method, callback) run_callback(method) end end # Delete existing callback # if callback == nil deletes all callbacks on given *method* # == Example # class Cat # include Callbacks # callback :after, :purr, :sleep # def purr # # purr # end # # def sleep # # sleep # end # end # # Cat.callbacks_exist?(:purr) # => true # Cat.del_callback(:purr) # Cat.callbacks_exist?(:purr) # => false def self.del_callback(method, callback = nil) if callback @@_method_chain[method].delete_if{|c| c == callback } del_all_callbacks(method) if @@_method_chain[method].size == 1 else del_all_callbacks(method) end end # Are callback *callback* on this method already exists? def self.callback_exists?(method, callback) !@@_method_chain[method.to_sym].detect{|c| c == callback.to_sym }.nil? end # Are callbacks on this method already exists? def self.callbacks_exist?(method) !@@_method_chain[method.to_sym].nil? end class << self def new_method_name(method) "#{method}_#{SALT}" end def method_added(method) if callbacks_exist?(method) && !@@_callbacks_running.include?(method) run_callback(method) end end private # Register new callback # See main example def callback(event, method, callback) reg_callback(event.to_sym, method.to_sym, callback.to_sym) end def del_all_callbacks(method) undef_method method alias_method method, new_method_name(method) @@_callbacks_running.delete_if {|m| m == method} @@_method_chain[method] = nil end def run_callback(method) return if @@_callbacks_running.include? method alias_method new_method_name(method), method undef_method method @@_callbacks_running.push method define_method method do call_method_chain(method) end end def reg_callback(event, method, callback) raise UnknownEventException if (event != :before && event != :after) @@_method_chain[method] = [new_method_name(method)] unless @@_method_chain[method] if event === :before reg_before_callback(method, callback) elsif event === :after reg_after_callback(method, callback) end end def reg_before_callback(method, callback) @@_method_chain[method].insert \ (@@_method_chain[method].index new_method_name(method)), callback end def reg_after_callback(method, callback) @@_method_chain[method].push callback end end def call_method_chain(method) result = nil @@_method_chain[method].each do |action| if action == self.class.new_method_name(method) result = self.send(action) else self.send(action) end end return result end end end |