announcement-test/app/models/bulletin_feed_cache.rb

class BulletinFeedCache
  include Mongoid::Document
  include Mongoid::Timestamps

	field :content, type: String, default: ''
	field :uid
	field :start
	field :end
	field :date
  field :invalid_date, type: DateTime
  def self.regenerate_all
  	caches = self.all.to_a
    time_now = Time.now
    caches.each do |cache|
      if cache.invalid_date && cache.invalid_date <= time_now
        cache.destroy
      else
        cache.regenerate
      end
    end
  	uids = BulletinFeed.all.pluck(:uid) - caches.collect(&:uid)
  	BulletinFeed.where(:uid.in=> uids).each do |feed|
  		feed.generate_one_cache()
  	end
  end
  def regenerate
  	st = self.start
  	et = self.end
  	dt = self.date
  	uid = self.uid
  	BulletinFeed.where(uid: uid).each{|v| v.generate_one_cache(startdt: st,enddt: et,dt: dt)} rescue nil
  	self.destroy
  end
end