001/*
002 * Licensed to the Apache Software Foundation (ASF) under one or more
003 * contributor license agreements.  See the NOTICE file distributed with
004 * this work for additional information regarding copyright ownership.
005 * The ASF licenses this file to You under the Apache License, Version 2.0
006 * (the "License"); you may not use this file except in compliance with
007 * the License.  You may obtain a copy of the License at
008 *
009 *      http://www.apache.org/licenses/LICENSE-2.0
010 *
011 * Unless required by applicable law or agreed to in writing, software
012 * distributed under the License is distributed on an "AS IS" BASIS,
013 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
014 * See the License for the specific language governing permissions and
015 * limitations under the License.
016 */
017package org.apache.commons.validator.routines.checkdigit;
018
019import java.io.Serializable;
020
021/**
022 * Combined <b>ISBN-10</b> / <b>ISBN-13</b> Check Digit calculation/validation.
023 * <p>
024 * This implementation validates/calculates ISBN check digits
025 * based on the length of the code passed to it - delegating
026 * either to the {@link ISBNCheckDigit#ISBN10_CHECK_DIGIT} or the
027 * {@link ISBNCheckDigit#ISBN13_CHECK_DIGIT} routines to perform the actual
028 * validation/calculation.
029 * <p>
030 * <b>N.B.</b> From 1st January 2007 the book industry will start to use a new 13 digit
031 * ISBN number (rather than this 10 digit ISBN number) which uses the EAN-13 / UPC
032 * standard.
033 *
034 * @version $Revision: 1227719 $ $Date: 2012-01-05 18:45:51 +0100 (Do, 05 Jan 2012) $
035 * @since Validator 1.4
036 */
037public final class ISBNCheckDigit implements CheckDigit, Serializable {
038
039    private static final long serialVersionUID = 1391849166205184558L;
040
041    /** Singleton ISBN-10 Check Digit instance */
042    public static final CheckDigit ISBN10_CHECK_DIGIT = ISBN10CheckDigit.ISBN10_CHECK_DIGIT;
043
044    /** Singleton ISBN-13 Check Digit instance */
045    public static final CheckDigit ISBN13_CHECK_DIGIT = EAN13CheckDigit.EAN13_CHECK_DIGIT;
046
047    /** Singleton combined ISBN-10 / ISBN-13 Check Digit instance */
048    public static final CheckDigit ISBN_CHECK_DIGIT   = new ISBNCheckDigit();
049
050    /**
051     * Calculate an ISBN-10 or ISBN-13 check digit, depending
052     * on the length of the code.
053     * <p>
054     * If the length of the code is 9, it is treated as an ISBN-10
055     * code or if the length of the code is 12, it is treated as an ISBN-13
056     * code.
057     *
058     * @param code The ISBN code to validate (should have a length of
059     * 9 or 12)
060     * @return The ISBN-10 check digit if the length is 9 or an ISBN-13
061     * check digit if the length is 12.
062     * @throws CheckDigitException if the code is missing, or an invalid
063     * length (i.e. not 9 or 12) or if there is an error calculating the
064     * check digit.
065     */
066    public String calculate(String code) throws CheckDigitException {
067        if (code == null || code.length() == 0) {
068            throw new CheckDigitException("ISBN Code is missing");
069        } else if (code.length() == 9) {
070            return ISBN10_CHECK_DIGIT.calculate(code);
071        } else if (code.length() == 12) {
072            return ISBN13_CHECK_DIGIT.calculate(code);
073        } else {
074            throw new CheckDigitException("Invalid ISBN Length = " + code.length());
075        }
076    }
077
078    /**
079     * <p>Validate an ISBN-10 or ISBN-13 check digit, depending
080     * on the length of the code.</p>
081     * <p>
082     * If the length of the code is 10, it is treated as an ISBN-10
083     * code or ff the length of the code is 13, it is treated as an ISBN-13
084     * code.
085     *
086     * @param code The ISBN code to validate (should have a length of
087     * 10 or 13)
088     * @return <code>true</code> if the code has a length of 10 and is
089     * a valid ISBN-10 check digit or the code has a length of 13 and is
090     * a valid ISBN-13 check digit - otherwise <code>false</code>.
091     */
092    public boolean isValid(String code) {
093        if (code == null) {
094            return false;
095        } else if (code.length() == 10) {
096            return ISBN10_CHECK_DIGIT.isValid(code);
097        } else if (code.length() == 13) {
098            return ISBN13_CHECK_DIGIT.isValid(code);
099        } else {
100            return false;
101        }
102    }
103
104}