if (rooms == null || rooms.size() == 0) return;
	public void setRooms(Collection rooms) {	    	    placeCoursePanel.removeAll();	    placeCourseJcb = new JComboBox(roomsName);	    placeCoursePanel.add(placeCourseJcb);	    placeCoursePanel.add(Box.createVerticalStrut(5));	    	    int cpt = 0;		int sizeRooms = rooms.size();				for(Iterator it = rooms.iterator(); it.hasNext(); ) {			Room room = (Room) it.next();						int pos = -1;						for(int i = 1; i < this.rooms.length; ++i) {				if (this.rooms[i].equals(room))					pos = i;			}						if (cpt == 0) {				placeCourseJcb.setSelectedIndex(pos);    											if (cpt != (sizeRooms-1))					placeCoursePlus.setText("x");  				}			else {				JComboBox jcb = new JComboBox(roomsName);								jcb.setSelectedItem(roomsName[pos]);								placeCoursePanel.add(jcb);				placeCoursePanel.add(Box.createVerticalStrut(5));								JButton plus;				if(cpt == (sizeRooms-1))					plus = new JButton("+");				else					plus = new JButton("x");								plus.addActionListener(new ButtonPlusListener(placeCoursePlusPanel, placeCoursePanel, AMCWFrame, roomsName));				placeCoursePlusPanel.add(plus);				placeCoursePlusPanel.add(Box.createVerticalStrut(5));			}			cpt++;		}	}