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 *      https://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
021import org.apache.commons.validator.GenericValidator;
022
023/**
024 * Combined <strong>ISBN-10</strong> / <strong>ISBN-13</strong> Check Digit calculation/validation.
025 * <p>
026 * This implementation validates/calculates ISBN check digits
027 * based on the length of the code passed to it - delegating
028 * either to the {@link ISBNCheckDigit#ISBN10_CHECK_DIGIT} or the
029 * {@link ISBNCheckDigit#ISBN13_CHECK_DIGIT} routines to perform the actual
030 * validation/calculation.
031 * </p>
032 * <p>
033 * <strong>N.B.</strong> From 1st January 2007 the book industry will start to use a new 13 digit
034 * ISBN number (rather than this 10 digit ISBN number) which uses the EAN-13 / UPC
035 * standard.
036 * </p>
037 *
038 * @since 1.4
039 */
040public final class ISBNCheckDigit extends AbstractCheckDigit implements Serializable {
041
042    private static final long serialVersionUID = 1391849166205184558L;
043
044    /**
045     * Singleton ISBN-10 Check Digit instance.
046     */
047    public static final CheckDigit ISBN10_CHECK_DIGIT = ISBN10CheckDigit.ISBN10_CHECK_DIGIT;
048
049    /**
050     * Singleton ISBN-13 Check Digit instance.
051     */
052    public static final CheckDigit ISBN13_CHECK_DIGIT = EAN13CheckDigit.EAN13_CHECK_DIGIT;
053
054    /**
055     * Singleton combined ISBN-10 / ISBN-13 Check Digit instance.
056     */
057    public static final CheckDigit ISBN_CHECK_DIGIT = new ISBNCheckDigit();
058
059    /**
060     * Constructs a new instance.
061     */
062    public ISBNCheckDigit() {
063        // empty
064    }
065
066    /**
067     * Calculate an ISBN-10 or ISBN-13 check digit, depending on the length of the code.
068     * <p>
069     * If the length of the code is 9, it is treated as an ISBN-10 code or if the length of the code is 12, it is treated as an ISBN-13 code.
070     * </p>
071     *
072     * @param code The ISBN code to validate (should have a length of 9 or 12).
073     * @return The ISBN-10 check digit if the length is 9 or an ISBN-13 check digit if the length is 12.
074     * @throws CheckDigitException if the code is missing, or an invalid length (that is, not 9 or 12) or if there is an error calculating the check digit.
075     */
076    @Override
077    public String calculate(final String code) throws CheckDigitException {
078        if (GenericValidator.isBlankOrNull(code)) {
079            throw new CheckDigitException("ISBN Code is missing");
080        }
081        if (code.length() == 9) { // CHECKSTYLE IGNORE MagicNumber
082            return ISBN10_CHECK_DIGIT.calculate(code);
083        }
084        if (code.length() == 12) { // CHECKSTYLE IGNORE MagicNumber
085            return ISBN13_CHECK_DIGIT.calculate(code);
086        }
087        throw new CheckDigitException("Invalid ISBN Length = %,d", code.length());
088    }
089
090    /**
091     * Validate an ISBN-10 or ISBN-13 check digit, depending on the length of the code.
092     * <p>
093     * If the length of the code is 10, it is treated as an ISBN-10 code or ff the length of the code is 13, it is treated as an ISBN-13 code.
094     * </p>
095     *
096     * @param code The ISBN code to validate (should have a length of 10 or 13).
097     * @return {@code true} if the code has a length of 10 and is a valid ISBN-10 check digit or the code has a length of 13 and is a valid ISBN-13 check digit
098     *         - otherwise {@code false}.
099     */
100    @Override
101    public boolean isValid(final String code) {
102        if (code == null) {
103            return false;
104        }
105        if (code.length() == 10) { // CHECKSTYLE IGNORE MagicNumber
106            return ISBN10_CHECK_DIGIT.isValid(code);
107        }
108        if (code.length() == 13) { // CHECKSTYLE IGNORE MagicNumber
109            return ISBN13_CHECK_DIGIT.isValid(code);
110        }
111        return false;
112    }
113}