socialforge/app/models/activity.rb

class Activity < ActiveRecord::Base
  attr_accessible :act_id, :act_type, :user_id
  belongs_to :act, :polymorphic => true
  belongs_to :user
  belongs_to :activity_container, polymorphic: true
  validates :act_id, presence: true
  validates :act_type, presence: true
  validates :user_id, presence: true

  include Trustie::Cache::ClearCourseEvent

  before_create :set_container_type_val

  #helper :activities
  include ActivitiesHelper
  def set_container_type_val
    params =get_container_type(self)
    self.activity_container_type = params[0]
    self.activity_container_id = params[1]
    if(self.act_type == 'JournalsForMessage')
      self.user_id = params[2]
    end
  end
end