    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;
    018
    019import java.io.Serializable;
    020import java.util.regex.Pattern;
    021
    022import org.apache.commons.validator.routines.checkdigit.CheckDigitException;
    023import org.apache.commons.validator.routines.checkdigit.EAN13CheckDigit;
    024import org.apache.commons.validator.routines.checkdigit.ISSNCheckDigit;
    025
    026/**
    027 * International Standard Serial Number (ISSN)
    028 * is an eight-digit serial number used to
    029 * uniquely identify a serial publication.
    030 * <pre>
    031 * The format is:
    032 *
    033 * ISSN dddd-dddC
    034 * where:
    035 * d = decimal digit (0-9)
    036 * C = checksum (0-9 or X)
    037 *
    038 * The checksum is formed by adding the first 7 digits multiplied by
    039 * the position in the entire number (counting from the right).
    040 *
    041 * For example, abcd-efg would be 8a + 7b + 6c + 5d + 4e +3f +2g.
    042 * The check digit is modulus 11, where the value 10 is represented by 'X'
    043 * For example:
    044 * ISSN 0317-8471
    045 * ISSN 1050-124X
    046 *
    047 * This class strips off the 'ISSN ' prefix if it is present before passing
    048 * the remainder to the checksum routine.
    049 *
    050 * </pre>
    051 * <p>
    052 * Note: the {@link #isValid(String)} and {@link #validate(String)} methods strip off any leading
    053 * or trailing spaces before doing the validation.
    054 * To ensure that only a valid code (without 'ISSN ' prefix) is passed to a method,
    055 * use the following code:
    056 * </p>
    057 * <pre>
    058 * Object valid = validator.validate(input);
    059 * if (valid != null) {
    060 *    some_method(valid.toString());
    061 * }
    062 * </pre>
    063 *
    064 * @since 1.5.0
    065 */
    066public class ISSNValidator implements Serializable {
    067
    068    private static final long serialVersionUID = 4319515687976420405L;
    069
    070    private static final Pattern DIGIT_DIGIT = Pattern.compile("\\d\\d");
    071
    072    private static final String ISSN_REGEX = "(?:ISSN )?(\\d{4})-(\\d{3}[0-9X])$"; // We don't include the '-' in the code, so it is 8 chars
    073
    074    private static final int ISSN_LEN = 8;
    075
    076    private static final String ISSN_PREFIX = "977";
    077
    078    private static final String EAN_ISSN_REGEX = "^(977)(?:(\\d{10}))$";
    079
    080    private static final int EAN_ISSN_LEN = 13;
    081
    082    private static final CodeValidator VALIDATOR = new CodeValidator(ISSN_REGEX, ISSN_LEN, ISSNCheckDigit.ISSN_CHECK_DIGIT);
    083
    084    private static final CodeValidator EAN_VALIDATOR = new CodeValidator(EAN_ISSN_REGEX, EAN_ISSN_LEN, EAN13CheckDigit.EAN13_CHECK_DIGIT);
    085
    086    /** ISSN Code Validator. */
    087    private static final ISSNValidator ISSN_VALIDATOR = new ISSNValidator();
    088
    089    /**
    090     * Gets the singleton instance of the ISSN validator.
    091     *
    092     * @return A singleton instance of the ISSN validator.
    093     */
    094    public static ISSNValidator getInstance() {
    095        return ISSN_VALIDATOR;
    096    }
    097
    098    /**
    099     * Constructs a new instance.
    100     */
    101    public ISSNValidator() {
    102        // empty
    103    }
    104
    105    /**
    106     * Converts an ISSN code to an EAN-13 code.
    107     * <p>
    108     * This method requires a valid ISSN code.
    109     * It may contain a leading 'ISSN ' prefix,
    110     * as the input is passed through the {@link #validate(String)}
    111     * method.
    112     * </p>
    113     *
    114     * @param issn The ISSN code to convert
    115     * @param suffix The two digit suffix, for example, "00"
    116     * @return A converted EAN-13 code or {@code null}
    117     * if the input ISSN code is not valid
    118     */
    119    public String convertToEAN13(final String issn, final String suffix) {
    120        if (suffix == null || !DIGIT_DIGIT.matcher(suffix).matches()) {
    121            throw new IllegalArgumentException("Suffix must be two digits: '" + suffix + "'");
    122        }
    123        final Object result = validate(issn);
    124        if (result == null) {
    125            return null;
    126        }
    127        // Calculate the new EAN-13 code
    128        final String input = result.toString();
    129        String ean13 = ISSN_PREFIX + input.substring(0, input.length() - 1) + suffix;
    130        try {
    131            final String checkDigit = EAN13CheckDigit.EAN13_CHECK_DIGIT.calculate(ean13);
    132            ean13 += checkDigit;
    133            return ean13;
    134        } catch (final CheckDigitException e) { // Should not happen
    135            throw new IllegalArgumentException("Check digit error for '" + ean13 + "' - " + e.getMessage());
    136        }
    137    }
    138
    139    /**
    140     * Extracts an ISSN code from an ISSN-EAN-13 code.
    141     * <p>
    142     * This method requires a valid ISSN-EAN-13 code with NO formatting
    143     * characters.
    144     * That is a 13 digit EAN-13 code with the '977' prefix.
    145     * </p>
    146     *
    147     * @param ean13 The ISSN code to convert
    148     * @return A valid ISSN code or {@code null}
    149     * if the input ISSN EAN-13 code is not valid
    150     * @since 1.7
    151     */
    152    public String extractFromEAN13(final String ean13) {
    153        String input = ean13.trim();
    154        if (input.length() != EAN_ISSN_LEN) {
    155            throw new IllegalArgumentException("Invalid length " + input.length() + " for '" + input + "'");
    156        }
    157        if (!input.startsWith(ISSN_PREFIX)) {
    158            throw new IllegalArgumentException("Prefix must be " + ISSN_PREFIX + " to contain an ISSN: '" + ean13 + "'");
    159        }
    160        final Object result = validateEan(input);
    161        if (result == null) {
    162            return null;
    163        }
    164        // Calculate the ISSN code
    165        input = result.toString();
    166        try {
    167            //CHECKSTYLE:OFF: MagicNumber
    168            final String issnBase = input.substring(3, 10); // TODO: how to derive these
    169            //CHECKSTYLE:ON: MagicNumber
    170            final String checkDigit = ISSNCheckDigit.ISSN_CHECK_DIGIT.calculate(issnBase);
    171            return issnBase + checkDigit;
    172        } catch (final CheckDigitException e) { // Should not happen
    173            throw new IllegalArgumentException("Check digit error for '" + ean13 + "' - " + e.getMessage());
    174        }
    175    }
    176
    177    /**
    178     * Tests whether the code is a valid ISSN code after any transformation
    179     * by the validate routine.
    180     *
    181     * @param code The code to validate.
    182     * @return {@code true} if a valid ISSN
    183     * code, otherwise {@code false}.
    184     */
    185    public boolean isValid(final String code) {
    186        return VALIDATOR.isValid(code);
    187    }
    188
    189    /**
    190     * Checks the code is valid ISSN code.
    191     * <p>
    192     * If valid, this method returns the ISSN code with
    193     * the 'ISSN ' prefix removed (if it was present)
    194     * </p>
    195     *
    196     * @param code The code to validate.
    197     * @return A valid ISSN code if valid, otherwise {@code null}.
    198     */
    199    public Object validate(final String code) {
    200        return VALIDATOR.validate(code);
    201    }
    202
    203    /**
    204     * Checks the code is a valid EAN code.
    205     * <p>
    206     * If valid, this method returns the EAN code
    207     * </p>
    208     *
    209     * @param code The code to validate.
    210     * @return A valid EAN code if valid, otherwise {@code null}.
    211     * @since 1.7
    212     */
    213    public Object validateEan(final String code) {
    214        return EAN_VALIDATOR.validate(code);
    215    }
    216}