BirthNumberValidator.java

BirthNumberValidator.java

//Copyright (c) 2013, Petr Prokop
//All rights reserved.
//
//Redistribution and use in source and binary forms, with or without
//modification, are permitted provided that the following conditions are met: 
//
//1. Redistributions of source code must retain the above copyright notice, this
//   list of conditions and the following disclaimer. 
//2. Redistributions in binary form must reproduce the above copyright notice,
//   this list of conditions and the following disclaimer in the documentation
//   and/or other materials provided with the distribution. 
//
//THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
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//WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
//DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR
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//of the authors and should not be interpreted as representing official policies, 
//either expressed or implied, of the FreeBSD Project.
package cz.zweistein.czechvalidations;

import java.util.Calendar;
import java.util.Date;

/**
 * 
 * This is validator of czech birth number (èeské rodné èíslo).
 * 
 * Checked items are:
 *  - Checksum
 *  - Validity of date
 *  - Sex
 *  - Date versus stated birth date
 *  - Basics (null, containing only numbers, etc...)
 *  
 * This class is unsuitable for validating insuarance number (èíslo pojištìnce),
 * which has slightly different format for foreigners where day of birth is offset by 50.
 * 
 * This class will also not work properly for birthNumbers issued after 2054.
 * 
 * This class may be used to validate slovak birth number (sloveské rodné èíslo)
 * which has identical format.
 * 
 * Example use:
 * 
 * boolean isValid = BirthNumberValidator.validateBirthNumber("8002104946");
 * 
 * Advanced use:
 * 
 *      boolean isValid = false;
 *      try {
 *              isValid = BirthNumberValidator.validateBirthNumberHarshly("8002104946", null, null);
 *      } catch (BirthNumberValidationException e) {
 *              // oh no!
 *      }
 * 
 * @author Petr Prokop <zwei2stein@gmail.com>
 * @version 1.0
 * @license FreeBSD License
 *
 */
public class BirthNumberValidator {
        
        /**
         * Utility method, see public boolean validateBirthNumber(String birthNumber, Date birthDate, Sex sex)
         * 
         * @param birthNumber
         * @return
         */
        public static boolean validateBirthNumber(String birthNumber) {
                return validateBirthNumber(birthNumber, null, Sex.UNSPECIFICED);
        }
        
        /**
         * Utility method, see public boolean validateBirthNumber(String birthNumber, Date birthDate, Sex sex)
         * 
         * @param birthNumber
         * @param birthDate
         * @return
         */
        public static boolean validateBirthNumber(String birthNumber, Date birthDate) {
                return validateBirthNumber(birthNumber, birthDate, Sex.UNSPECIFICED);
        }
        
        /**
         * Utility method, see public boolean validateBirthNumber(String birthNumber, Date birthDate, Sex sex)
         * 
         * @param birthNumber
         * @param sex
         * @return
         */
        public static boolean validateBirthNumber(String birthNumber, Sex sex) {
                return validateBirthNumber(birthNumber, null, sex);
        }
        
        /**
         * Validates czech birth number (rodné èíslo).
         * 
         * Checked items are:
         *  - Checksum
         *  - Validity of date
         *  - Sex
         *  - Date versus stated birth date
         *  - Basics (null, containing only numbers, etc...)
         * 
         * @param birthNumber - birth number in YYMMDDCCCC format without slash or dash
         * @param birthDate - date of birth of person whose birth nuber we are validating, null if not available
         * @param sex - sex of person whose birth we are validating, null or Sex.UNSPECIFIED if not available.
         * @return true if birth number is validù
         */
        public static boolean validateBirthNumber(String birthNumber, Date birthDate, Sex sex) {
                try {
                        return validateBirthNumberHarshly(birthNumber, birthDate, sex);
                } catch (BirthNumberValidationException e) {
                        return false;
                }
        }
        
        /**
         * See public static boolean validateBirthNumber(String birthNumber, Date birthDate, Sex sex) for paramters
         * 
         * This method returns true if birth number is valid but throws exception if it is invalid
         * 
         * @param birthNumber
         * @param birthDate
         * @param sex
         * @return
         * @throws BirthNumberValidationException
         */
        public static boolean validateBirthNumberHarshly(String birthNumber, Date birthDate, Sex sex) throws BirthNumberValidationException {

                if (birthNumber == null) {
                        throw new BirthNumberValidationException("Input parameter is null.", BirthNumberValidityError.NULL_PARAM);
                } else if (birthNumber.length() != 10 && birthNumber.length() != 9) {
                        throw new BirthNumberValidationException("Input parameter is not 9 or 10 characters long.", BirthNumberValidityError.INVALID_LENGTH);
                } else if (!birthNumber.matches("[0-9]+")) {
                        throw new BirthNumberValidationException("Input parameter does not contain only numbers.", BirthNumberValidityError.NONNUMERIC_CHARACTER);
                } else {

                        int year = Integer.parseInt(birthNumber.substring(0, 2));
                        int month = Integer.parseInt(birthNumber.substring(2, 4));
                        int day = Integer.parseInt(birthNumber.substring(4, 6));
                        //int ext = Integer.parseInt(birthNumber.substring(6, 9)); //not used for validation

                        if (birthNumber.length() == 9) {
                                // before year 1954, rc were only 9 digit numbers, 10 digit is invalid
                                if ( year < 54) {
                                        return true;
                                } else {
                                        throw new BirthNumberValidationException("Nine digit birth number after year 1954.", BirthNumberValidityError.NINE_DIGITS_BEFROE_1954);
                                }
                        } else {

                                int checkDigit = Integer.parseInt(birthNumber.substring(9));
                                int mod11 = Integer.parseInt(birthNumber.substring(0, 9)) % 11;

                                if (mod11 == 10) {
                                        mod11 = 0;
                                }
                                if (mod11 != checkDigit) {
                                        throw new BirthNumberValidationException("Mod 11 checksum not matching.", BirthNumberValidityError.MOD_11_CHECKSUM_FAILUE);
                                }

                                // restoring year of birth.
                                if (year < 54) {
                                        year = 2000 + year;
                                } else {
                                        year = 1900 + year;
                                }

                                // month > 50 means that birth number belongs to female
                                if (month > 50 && Sex.MALE.equals(sex)) {
                                        throw new BirthNumberValidationException("Supplied sex not matching.", BirthNumberValidityError.SEX_MISMATCH);
                                } else if (month < 50 && Sex.FEMALE.equals(sex)) {
                                        throw new BirthNumberValidationException("Supplied sex not matching.", BirthNumberValidityError.SEX_MISMATCH);
                                }

                                // removing sex offsets from month of birth.
                                if (month > 70 && year > 2003) {
                                        month -= 70;
                                } else if (month > 50) {
                                        month -= 50;
                                } else if (month > 20 && year > 2003) {
                                        month -= 20;
                                }

                                Calendar cal = Calendar.getInstance();
                                cal.setLenient(false); // makes calendar throw exception on invalid date
                                try {
                                        cal.set(year, month - 1, day); // month starts at 0
                                        Date date = cal.getTime();

                                        if (birthDate != null) {
                                                if (!date.equals(birthDate)) {
                                                        throw new BirthNumberValidationException("Supplied birth date not matching.", BirthNumberValidityError.BIRTH_DATE_MISMATCH);
                                                }
                                        }

                                } catch (IllegalArgumentException e) {
                                        throw new BirthNumberValidationException("Invalid birth date.", BirthNumberValidityError.INVALID_DATE);
                                }

                        }
                }

                return true;

        }

}