class CalculationTasks implements ImmutableBean {

  @Override
  public String toString() {
    return Messages.format("CalculationTasks[grid={}x{}]", targets.size(), columns.size());
  }

  private  CalculationTasks(List<CalculationTask> tasks, List<Column> columns);
  private  CalculationTasks(
      List<CalculationTarget> targets,
      List<Column> columns,
      List<CalculationTask> tasks);

}