RandomUtil.java

/**
 *
 * Copyright (c) 2014, the Railo Company Ltd. All rights reserved.
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either 
 * version 2.1 of the License, or (at your option) any later version.
 * 
 * This library is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Lesser General Public License for more details.
 * 
 * You should have received a copy of the GNU Lesser General Public 
 * License along with this library.  If not, see <http://www.gnu.org/licenses/>.
 * 
 **/
package lucee.commons.lang;

import java.security.SecureRandom;

public class RandomUtil {
	public static final char[]  CHARS=new char[]{
		'0','1','2','3','4','5','6','7','8','9',
		'A','B','C','D','E','F','G','H','I','J','K','L','M','N','O','P','Q','R','S','T','U','V','W','X','Y','Z',
		'a','b','c','d','e','f','g','h','i','j','k','l','m','n','o','p','q','r','s','t','u','v','w','x','y','z'};
	
	public static final char[]  CHARS_LC=new char[]{
		'0','1','2','3','4','5','6','7','8','9',
		'a','b','c','d','e','f','g','h','i','j','k','l','m','n','o','p','q','r','s','t','u','v','w','x','y','z'};
	

	public static String createRandomString(int length){
		if(length<1) return "";
		SecureRandom sr = new SecureRandom();
		StringBuilder sb=new StringBuilder();
		for(int i=0;i<length;i++){
			int rnd=(int) (sr.nextDouble()*(CHARS.length-1));
			sb.append(CHARS[rnd]);
		}
		return sb.toString();
	}
	
	public static String createRandomStringLC(int length){
		if(length<1) return "";
		SecureRandom sr = new SecureRandom();
		StringBuilder sb=new StringBuilder();
		for(int i=0;i<length;i++){
			int rnd=(int) (sr.nextDouble()*(CHARS_LC.length-1));
			sb.append(CHARS_LC[rnd]);
		}
		return sb.toString();
	}
}