Java tutorial
/* * Licensed to the Apache Software Foundation (ASF) under one * or more contributor license agreements. See the NOTICE file * distributed with this work for additional information * regarding copyright ownership. The ASF licenses this file * to you under the Apache License, Version 2.0 (the * "License"); you may not use this file except in compliance * with the License. You may obtain a copy of the License at * * http://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, * software distributed under the License is distributed on an * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY * KIND, either express or implied. See the License for the * specific language governing permissions and limitations * under the License. */ package org.apache.syncope.core.spring.security; import org.apache.commons.text.RandomStringGenerator; import org.apache.syncope.common.lib.SecureTextRandomProvider; public final class SecureRandomUtils { private static final RandomStringGenerator FOR_PASSWORD = new RandomStringGenerator.Builder() .usingRandom(new SecureTextRandomProvider()) .filteredBy( codePoint -> (codePoint >= 'a' && codePoint <= 'z') || (codePoint >= '0' && codePoint <= '9')) .build(); private static final RandomStringGenerator FOR_LETTERS = new RandomStringGenerator.Builder() .usingRandom(new SecureTextRandomProvider()).withinRange('a', 'z').build(); private static final RandomStringGenerator FOR_NUMBERS = new RandomStringGenerator.Builder() .usingRandom(new SecureTextRandomProvider()).withinRange('0', '9').build(); public static String generateRandomPassword(final int tokenLength) { return FOR_PASSWORD.generate(tokenLength); } public static String generateRandomLetter() { return FOR_LETTERS.generate(1); } public static String generateRandomNumber() { return FOR_NUMBERS.generate(1); } public static String generateRandomSpecialCharacter(final char[] characters) { return new RandomStringGenerator.Builder().usingRandom(new SecureTextRandomProvider()) .filteredBy(codePoint -> { boolean found = false; for (int i = 0; i < characters.length && !found; i++) { found = codePoint == Character.codePointAt(characters, i); } return found; }).build().generate(1); } private SecureRandomUtils() { // private constructor for static utility class } }