code: /*
   * Computoser is a music-composition algorithm and a website to present the results
   * Copyright (C) 2012-2014  Bozhidar Bozhanov
   *
   * Computoser is free software: you can redistribute it and/or modify
   * it under the terms of the GNU Affero General Public License as
   * published by the Free Software Foundation, either version 3 of the
   * License, or (at your option) any later version.
   *
   * Computoser 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 Affero General Public License for more details.
   *
   * You should have received a copy of the GNU Affero General Public License
   * along with Computoser.  If not, see <http://www.gnu.org/licenses/>.
   */
  
  package com.music.util.music;
  
  import java.util.Random;
  
  public class Chance {
      private static final Random random = new Random();
  
      public static boolean test(int percentage) {
          if (percentage >= random.nextInt(100) + 1) {
              return true;
          } else {
              return false;
          }
      }
  
      public static int choose(int[] percentages) {
          int rand = random.nextInt(100) + 1;
          int sum = 0;
          for (int i = 0; i < percentages.length; i++) {
              sum += percentages[i];
              if (sum > 100) {
                  throw new IllegalStateException("Percentages exceed 100");
              }
              if (rand <= sum) {
                  return i;
              }
          }
          throw new IllegalStateException("Percentages passed do not go up to 100");
      }
  }
  