/*

  * Copyright 2007-2008 The Kuali Foundation

  *

  * Licensed under the Educational Community 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.opensource.org/licenses/ecl2.php

  *

  * 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.kuali.rice.kim.sesn;

 import java.security.SecureRandom;

 /**

  * This class generates a random string for creating Distributed Session Tickets 

  * 

  * @author Kuali Rice Team (rice.collab@kuali.org)

  *

  */

 public class SessionIdGenerator {

     /** The array of printable characters to be used in our random string. */

     private static final char[] PRINTABLE_CHARACTERS = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ012345679"

         .toCharArray();

     private static final SecureRandom randomizer = new SecureRandom();

     public static String getNewString() {

         final byte[] random = getNewStringAsBytes();

         return convertBytesToString(random);

     }

     private static byte[] getNewStringAsBytes() {

         final byte[] random = new byte[40];

         randomizer.nextBytes(random);

         return random;

     }

     private static String convertBytesToString(final byte[] random) {

         final char[] output = new char[random.length];

         for (int i = 0; i < random.length; i++) {

             final int index = Math.abs(random[i] % PRINTABLE_CHARACTERS.length);

             output[i] = PRINTABLE_CHARACTERS[index];

         }

         return new String(output);

     }

 }