Java tutorial
// Copyright 2015 HSL <https://www.hsl.fi> // This program is dual-licensed under the EUPL v1.2 and AGPLv3 licenses. package fi.hsl.parkandride.core.service; import java.util.ArrayList; import java.util.Collection; import java.util.regex.Pattern; import org.springframework.util.StringUtils; import fi.hsl.parkandride.core.domain.Violation; public class PasswordValidator { private PasswordValidator() { } private static final Pattern PATTERN = Pattern.compile("^" + // start "(?=.*\\d)" + // at least one digit "(?=.*[a-z])" + // at least one lowercase letter "(?=.*[A-Z])" + // at least one uppercase letter "(?!.*\\s)" + // no whitespace inside "." + // everything provided that the previous condition checks pass "{8,15}" + // min max length "$" // end ); public static void validate(String password) { Collection<Violation> violations = new ArrayList<>(); validate(password, violations); if (!violations.isEmpty()) { throw new ValidationException(violations); } } public static void validate(String password, Collection<Violation> violations) { if (!StringUtils.hasText(password) || !PATTERN.matcher(password).matches()) { violations.add(new Violation("BadPassword", "password", "Password with length of 8-15 must contain at least one digit, one lowercase and one uppercase character")); } } }