private Boolean checkData(String kod,String diad){
		/*
		 * elegxei an einai swsta ta dedomena pou exoun do8ei
		 */
		if(kod.length()<2){
			JOptionPane.showMessageDialog(null, "Dwste egkuro kwdiko!");
			return false;
		}else if(diad.length()<3){
			JOptionPane.showMessageDialog(null, "Dwste egkiri diadromh!");
			return false;
		}else{
			return true;
		}
		
		
	}