protected void sendVisitsQueryByLessonSelect(GroupLesson lesson) {
   for (GroupLesson gLesson : jC.getLessons(selectedGroup, selectedSemester)) {
     if (gLesson.equals(lesson)) {
       selectedLesson = gLesson;
       break;
     }
   }
   jC.sendGroupVisitsQuery(selectedLesson);
 }
 protected void sendVisitsQueryByGroupSelect(GroupLesson[] groupLessons) {
   lessonsSelector.setLessons(groupLessons);
   for (GroupLesson lesson : groupLessons) {
     if (lesson.equals(selectedLesson)) {
       jC.sendGroupVisitsQuery(lesson);
       return;
     }
   }
   if (groupLessons.length != 0) {
     selectedLesson = groupLessons[0];
     jC.sendGroupVisitsQuery(selectedLesson);
   }
   lessonsSelector.setLessonTitle(selectedLesson);
 }