code: public static Predicate not(final Predicate childPredicate) {
          return new Predicate() {
              public void init(AbstractSqlCreator creator) {
                  childPredicate.init(creator);
              }
              public String toSql() {
                  return "not (" + childPredicate.toSql() + ")";
              }
          };
      }
docs: Inverts the sense of the given child predicate. In SQL terms, this
  surrounds the given predicate with "not (...)".
  
  @param childPredicate
  Predicate whose sense is to be inverted.