socialforge/app/models/exercise.rb

class Exercise < ActiveRecord::Base
  #exercise_status: 1,新建；2，发布；3，关闭
  include Redmine::SafeAttributes
  belongs_to :user
  belongs_to :course ,:touch => true
  has_many :exercise_questions, :dependent => :destroy,:order => "#{ExerciseQuestion.table_name}.question_number"
  has_many :exercise_users, :dependent => :destroy
  has_many :users, :through => :exercise_users #该测试被哪些用户提交答案过
  # 课程消息
  has_many :course_messages, :class_name =>'CourseMessage', :as => :course_message, :dependent => :destroy
  after_create :acts_as_course_message
  def acts_as_course_message
    if self.course
      if self.exercise_status == 2 #未发布
        #self.course.members.each do |m|
          self.course_messages << CourseMessage.create(:user_id => User.current.id, :course_id => self.course_id, :viewed => false,:status=>2)
        #end
      # else
      #   self.course_messages.destroy_all 这里的destory_all值得商榷。因为我这里是通过status来控制不同的status的
      end
    end
  end
end