The court shall permit one or more members of a class to sue or be sued as representative parties on behalf of the class only if:

1. (1) the class is so numerous that joinder of all members is impracticable;
2. (2) there are questions of law or fact common to the class;
3. (3) the claims or defenses of the representative parties are typical of the claims or defenses of the class; and
4. (4) the representative parties will fairly and adequately protect the interests of the class.

Added by Acts 2003, 78th Leg., ch. 1274, Sec. 2, eff. April 1, 2005.