/// <summary>
        /// Default constructur
        /// </summary>
        public ObjectCommentRepository()
        {
            _comments = new Collection<CommentEntity>();

            Random rand = new Random();
            for (long i = 1; i < Repository.UserPostRepositoryInstance.GetCount(); i++)
            {
                // random count of comments for post
                for (int j = 1; j < rand.Next(1, 100); j++)
                {
                    if (Repository.UserPostRepositoryInstance.IsExists(i))
                    {
                        CommentEntity comment = new CommentEntity();
                        comment.Id = identityIdCounter++;
                        comment.CreatedUTC = DateTime.Now;
                        comment.PostId = i;
                        comment.UserId = Repository.UserPostRepositoryInstance.Get(i).AuthorUserId;
                        comment.Message = "";
                        for (int k = 0; k < rand.Next(1, 10); k++)
                            comment.Message += "Nice post!";

                        _comments.Add(comment);
                    }
                }
            }
        }
        /// <summary>
        /// Create comment
        /// </summary>
        /// <param name="comment"></param>
        /// <returns>created comment</returns>
        public bool Create(CommentEntity comment)
        {
            bool createResult = false;

            if (comment != null)
            {
                _comments.Add(comment);
                createResult = true;
            }

            return createResult;
        }
        /// <summary>
        /// Update comment
        /// </summary>
        /// <param name="comment"></param>
        /// <returns>updated comment</returns>
        public bool Update(CommentEntity comment)
        {
            bool updateResult = false;

            CommentEntity old = _comments.SingleOrDefault(c => c.Id == comment.Id);

            if (old != null)
            {
                old.Message = comment.Message;
                updateResult = true;
            }

            return updateResult;
        }