* Copyright (c) 2012, Francis Galiegue <firstname.lastname@example.org>
* This program is free software: you can redistribute it and/or modify
* it under the terms of the Lesser GNU General Public License as
* published by the Free Software Foundation, either version 3 of the
* License, or (at your option) any later version.
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* Lesser GNU General Public License for more details.
* You should have received a copy of the GNU General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
As an extra step, this validator also ensures that the number in the
instance is not negative, and does not overflow: Java's
may return a long, but internally the return code
is a signed 32-bit integer, therefore must not be greater than 2^31 - 1.