/*
 * 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.knox.gateway.util;

import java.security.SecureRandom;

public class PasswordUtils {
  private static final SecureRandom SECURE_RANDOM = new SecureRandom();
  private static final char[] ALPHANUMERIC_CHARS = { 'a', 'b', 'c', 'd', 'e', 'f', 'g',
      'h', 'j', 'k', 'm', 'n', 'p', 'q', 'r', 's', 't', 'u', 'v', 'w',
      'x', 'y', 'z', 'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H', 'J', 'K',
      'M', 'N', 'P', 'Q', 'R', 'S', 'T', 'U', 'V', 'W', 'X', 'Y', 'Z',
      '2', '3', '4', '5', '6', '7', '8', '9',};

  private PasswordUtils() {}

  public static synchronized String generatePassword(int length) {
    StringBuilder sb = new StringBuilder();
    for (int i = 0; i < length; i++) {
      sb.append(ALPHANUMERIC_CHARS[SECURE_RANDOM.nextInt(ALPHANUMERIC_CHARS.length)]);
    }
    return sb.toString();
  }
}
