Java tutorial
//package com.java2s; /* * Copyright (C) 2009 - 2012 SMVP4G.COM * * This 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 3 of * the License, or (at your option) any later version. * * This software 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 software; if not, write to the Free * Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA * 02110-1301 USA, or see the FSF site: http://www.fsf.org. */ import java.util.*; public class Main { /** * Scramble oder of elements in a list. * * @param list */ public static <E> void scrambleList(List<E> list) { if (isNotEmpty(list)) { Random generator = new Random(); for (int i = 0; i < list.size(); i++) { int random = generator.nextInt(list.size()); if (random != i) { //Util of vs.(swap) E objTemp = list.get(i); list.set(i, list.get(random)); list.set(random, objTemp); } } } } /** * Using like isEmpty but it check a collection is not empty or not. * * @param collection * @return false if this collection is null or empty. */ public static boolean isNotEmpty(Collection<?> collection) { return !isEmpty(collection); } /** * Check a collection is empty or not. * * @param collection * @return true if this collection is null or empty. */ public static boolean isEmpty(Collection<?> collection) { return collection == null || collection.isEmpty(); } }