This week's book giveaway is in the OCPJP forum. We're giving away four copies of OCA/OCP Java SE 7 Programmer I & II Study Guide and have Kathy Sierra & Bert Bates on-line! See this thread for details.
Scott, The easiest thing to do is leave them separate. I can't think of any way to check all three of these things. Note your requirements say the max length is 16 and your reg exp is 24. I assume one is a typo, but I figured I would mention it.