/***
 * Excerpted from "Domain-Driven Design Using Naked Objects",
 * published by The Pragmatic Bookshelf.
 * Copyrights apply to this code. It may not be used to create training material, 
 * courses, books, articles, and the like. Contact us if you are in doubt.
 * We make no guarantees that this code is fit for any purpose. 
 * Visit http://www.pragmaticprogrammer.com/titles/dhnako for more book information.
***/
@MustSatisfy(RegistrationNumberSpecification.class)
@RegEx(validation="[A-Z0-9 ]+", caseSensitive=false)
public final class RegistrationNumber {
    ...
}
