/* * #%L * BroadleafCommerce Common Libraries * %% * Copyright (C) 2009 - 2013 Broadleaf Commerce * %% * Licensed under the Apache License, Version 2.0 (the "License"); * you may not use this file except in compliance with the License. * You may obtain a copy of the License at * * http://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, software * distributed under the License is distributed on an "AS IS" BASIS, * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. * See the License for the specific language governing permissions and * limitations under the License. * #L% */ package org.broadleafcommerce.common.util; public class Mod43CheckDigitUtil { private final static String CHARSET = "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ-. $/+%"; public static boolean isValidCheckedValue(String value) { boolean valid = false; if (value != null && !"".equals(value)) { String code = value.substring(0, value.length() - 1); char checkDigit = value.substring(value.length() - 1).charAt(0); try { if (generateCheckDigit(code) == checkDigit) { valid = true; } } catch (Exception e) { e.printStackTrace(); } } return valid; } public static char generateCheckDigit(String data) { // MOD 43 check digit - take the acsii value of each digit, sum them up, divide by 43. the remainder is the check digit (in ascii) int sum = 0; for (int i = 0; i < data.length(); ++i) { sum += CHARSET.indexOf(data.charAt(i)); } int remainder = sum % 43; return CHARSET.charAt(remainder); } public static void main(String[] args) { try { System.out.println(generateCheckDigit("TEACH000012345")); } catch (Exception e) { e.printStackTrace(); } System.out.println(isValidCheckedValue("TEACH000012345B")); } }