    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
    019/**
    020 * Modulus 10 <strong>SEDOL</strong> (UK Securities) Check Digit calculation/validation.
    021 *
    022 * <p>
    023 * SEDOL Numbers are 7 character alphanumeric codes used
    024 * to identify UK Securities (SEDOL stands for Stock Exchange Daily Official List).
    025 * </p>
    026 * <p>
    027 * Check digit calculation is based on <em>modulus 10</em> with digits being weighted
    028 * based on their position, from left to right, as follows:
    029 * </p>
    030 * <pre>{@code
    031 *      position:  1  2  3  4  5  6  7
    032 *     weighting:  1  3  1  7  3  9  1
    033 * }</pre>
    034 * <p>
    035 * See <a href="https://en.wikipedia.org/wiki/SEDOL">Wikipedia - SEDOL</a>
    036 * for more details.
    037 * </p>
    038 *
    039 * @since 1.4
    040 */
    041public final class SedolCheckDigit extends ModulusCheckDigit {
    042
    043    private static final long serialVersionUID = -8976881621148878443L;
    044
    045    private static final int MAX_ALPHANUMERIC_VALUE = 35; // Character.getNumericValue('Z')
    046
    047    /** Singleton SEDOL check digit instance */
    048    public static final CheckDigit SEDOL_CHECK_DIGIT = new SedolCheckDigit();
    049
    050    /** Weighting given to digits depending on their right position */
    051    private static final int[] POSITION_WEIGHT = {1, 3, 1, 7, 3, 9, 1};
    052
    053    /**
    054     * Constructs a modulus 10 Check Digit routine for ISBN-10.
    055     */
    056    public SedolCheckDigit() {
    057    }
    058
    059    /**
    060     * Calculate the modulus for an SEDOL code.
    061     *
    062     * @param code The code to calculate the modulus for.
    063     * @param includesCheckDigit Whether the code includes the Check Digit or not.
    064     * @return The modulus value
    065     * @throws CheckDigitException if an error occurs calculating the modulus
    066     * for the specified code
    067     */
    068    @Override
    069    protected int calculateModulus(final String code, final boolean includesCheckDigit) throws CheckDigitException {
    070        if (code.length() > POSITION_WEIGHT.length) {
    071            throw new CheckDigitException("Invalid Code Length = " + code.length());
    072        }
    073        return super.calculateModulus(code, includesCheckDigit);
    074    }
    075
    076    /**
    077     * Convert a character at a specified position to an integer value.
    078     *
    079     * @param character The character to convert
    080     * @param leftPos The position of the character in the code, counting from left to right
    081     * @param rightPos The position of the character in the code, counting from right to left
    082     * @return The integer value of the character
    083     * @throws CheckDigitException if character is not alphanumeric
    084     */
    085    @Override
    086    protected int toInt(final char character, final int leftPos, final int rightPos) throws CheckDigitException {
    087        final int charValue = Character.getNumericValue(character);
    088        // the check digit is only allowed to reach 9
    089        final int charMax = rightPos == 1 ? 9 : MAX_ALPHANUMERIC_VALUE; // CHECKSTYLE IGNORE MagicNumber
    090        if (charValue < 0 || charValue > charMax) {
    091            throw new CheckDigitException("Invalid Character[" + leftPos + "," + rightPos + "] = '" + charValue + "' out of range 0 to " + charMax);
    092        }
    093        return charValue;
    094    }
    095
    096    /**
    097     * Calculates the <em>weighted</em> value of a character in the
    098     * code at a specified position.
    099     *
    100     * @param charValue The numeric value of the character.
    101     * @param leftPos The position of the character in the code, counting from left to right
    102     * @param rightPos The position of the character in the code, counting from right to left
    103     * @return The weighted value of the character.
    104     */
    105    @Override
    106    protected int weightedValue(final int charValue, final int leftPos, final int rightPos) {
    107        return charValue * POSITION_WEIGHT[leftPos - 1];
    108    }
    109
    110}