Robust validation of Swedish personal ID in java

SwedishIdUtils.java

import java.util.Calendar;

public class SwedishIdUtils {

    public static boolean validateId(String id) {
        // Only allow digits, whitespace + and - (+ is sometimes used to indicate age greater than 100 years)
        if (id == null || !id.matches("^[\\-\\s\\+\\d]+$")) {
            return false;
        }
        // Remove all non digits
        String in = id.replaceAll("\\D", "");
        if (in.length() != 10 && in.length() != 12) {
            return false;
        }
        if (in.length() == 12) {
            // Validate century prefix and reduce string that is to be validated to 10 digits
            // Other prefixes than these indicate that it is a company
            int prefix = Integer.parseInt(in.substring(0, 2));
            if (prefix < 18 || prefix > 20) {
                return false;
            }
            // Validate that year is not greater than current
            int currentYear = Calendar.getInstance().get(Calendar.YEAR);
            if (Integer.parseInt(in.substring(0, 4)) > currentYear) {
                return false;
            }
            in = in.substring(2);
        }
        int sum = 0;
        for (int i = 0; i < in.length(); i++) {
            int value = Character.getNumericValue(in.charAt(i));
            sum += getValidationValue(i, value);
        }
        return sum % 10 == 0;
    }

    private static int getValidationValue(int index, int baseValue) {
        if (index % 2 != 0) {
            return baseValue;
        }
        int doubled = 2 * baseValue;
        if (doubled < 10) {
            return doubled;
        } else {
            return 1 + (doubled - 10);
        }
    }

}