public Tweet()
 {
     hashtag = Hashtag.Instance;
     mention = Mention.Instance;
     txtAbbreviation = TxtAbbreviation.Instance;
     type = "tweet";
 }
        public Tweet(string id, string messageTxt, string sender)
        {
            hashtag = Hashtag.Instance;
            mention = Mention.Instance;
            type = "tweet";
            this.messageTxt = messageTxt;
            this.sender = sender;
            this.id = id;
            txtAbbreviation = TxtAbbreviation.Instance;

            this.processAbbreviations();
            this.processHashtags();
            this.processMentions();
        }