public void goToWizardStep(WizardStep step) {
    currentStep = step;
    view.showPrevButton(step.hasPrev());
    view.showNextButton(step.hasNext());

    switch (step) {
      case START:
        view.showStartStep(budget);
        break;
      case INCOMES:
        view.showIncomesStep(budget);
        break;
      case EXPENSES:
        view.showExpensesStep(budget);
        break;
      case FINISH:
        view.showFinishStep(budget);
        break;
      default:
        break;
    }
  }
 public void goPrevStep() {
   if (currentStep.hasPrev()) {
     goToWizardStep(currentStep.getPrev());
   }
 }