ArEvents
========

This is a Rails plugin enabling you to define listeners to ActiveRecord events.
It has the same goals as the ActiveRecord observers, but is more flexible as it
lets you define the listeners anywhere in your code.

A listener is simply a ruby class having a class method named trigger that
takes 2 arguments: the event fired and the object fireing the event.

To access the functionality in a model, just include the ArEvents module.


Example
=======

This code comes from the tests.
If you have a model defined:

class ArEventComment < ActiveRecord::Base
end

You can add the module to get access the the ArEvents funtionality:

	ArEventComment.extend ArEvents

Simply define a listener:

	class ArEventCommentListener
	  def self.trigger(evt, obj)
	    puts "event #{evt} triggered by object #{obj.inspect}"
	  end
	end

and attach it to the class you want to monitor, specifying the event to watch for:

	ArEventComment.add_ar_event_listener(:before_validation, ArEventCommentListener)

Now, each time an ArEventComment is validated, the ArEventCommentListener will be triggered:

	@comment = ArEventComment.new
	@comment.valid?
	# event before_validation triggered by object #<ArEventComment ...>

It works with inheritance, but the module needs to be included in every subclass.

Events can be selectively ignored:

	ArEventComment.ignore_ar_events(:before_create)
	#some code
	ArEventComment.ignore_ar_events(:before_create)

or with a block of code:

	ArEventComment.ignore_ar_events(:before_create) do 
		#some code
	end

Copyright (c) 2009 Raphaël Bauduin, released under the MIT license