Fortress

  /**
   * Checks the invariant "Condition is true" and
   * throws an exception if it is violated.
   *  
   * @param condition Condition to be checked.
   * 
   * @throws IllegalArgumentException if the invariant is violated
   * ({@code condition} is {@code false}).
   */
  public static void checkTrue(final boolean condition) {
    if (!condition) {
      throw new IllegalArgumentException();
    }
  }