XmlPullParser

List<SubstitutionDay> parseReturnSubstitution() {
        SubstitutionDay currentSubstitutionDay = new SubstitutionDay();
        List<SubstitutionDay> results = new ArrayList<>();
        Substitution currentSubstitution = new Substitution();
        List<Substitution> currentSubstitutionList = new ArrayList<>();
        int multipleClasses = 0, multiplePeriods = 0;
        String text = "";

        try {
            XmlPullParserFactory xmlPullParserFactory = XmlPullParserFactory.newInstance();
            xmlPullParserFactory.setNamespaceAware(true);
            XmlPullParser xmlPullParser = xmlPullParserFactory.newPullParser();
            xmlPullParser.setInput(bufferedReader);

            int eventType = xmlPullParser.getEventType();

            while (eventType != END_DOCUMENT) {
                String tag;
                String attributeName = "";
                String attributeValue = "";
                String[] tempStringArray;

                tag = xmlPullParser.getName();
                switch (eventType) {
                    case TEXT:
                        text = xmlPullParser.getText();
                        break;

                    case START_TAG:
                        if (xmlPullParser.getAttributeCount() > 0) {
                            attributeName = xmlPullParser.getAttributeName(0);
                            attributeValue = xmlPullParser.getAttributeValue(0);
                        }
                        switch (tag) {
                            case "kopf":
                                currentSubstitutionDay = new SubstitutionDay();
                                break;
                            case "haupt":
                                currentSubstitutionList.clear();
                                Log.i(TAG, "cleared list - elements: " + currentSubstitutionList.size());
                            case "aktion":
                                currentSubstitution = new Substitution();
                                multipleClasses = 0;
                                multiplePeriods = 0;
                                break;
                            case "fach":
                                if (attributeName.equalsIgnoreCase("fageaendert") && attributeValue.equalsIgnoreCase("ae")) {
                                    currentSubstitution.setChanges(currentSubstitution.getChanges() + "subject|");
                                }
                                break;
                            case "lehrer":
                                if (attributeName.equalsIgnoreCase("legeaendert") && attributeValue.equalsIgnoreCase("ae")) {
                                    currentSubstitution.setChanges(currentSubstitution.getChanges() + "teacher|");
                                }
                                break;
                            case "raum":
                                if (attributeName.equalsIgnoreCase("rageaendert") && attributeValue.equalsIgnoreCase("ae")) {
                                    currentSubstitution.setChanges(currentSubstitution.getChanges() + "room|");
                                }
                                break;
                        }
                        break;

                    case END_TAG:
                        switch (tag) {
                            // all data stored as header data
                            case "titel":
                                tempStringArray = text.split("[,(]");
                                String weekString = tempStringArray[2].substring(0, 1);

                                String dateString = tempStringArray[1].trim();
                                long date = dateFormatterMonthName.parse(dateString).getTime();

                                currentSubstitutionDay.setDate(date);
                                currentSubstitutionDay.setWeek(weekString);
                                break;
                            case "schulname":
                                int id = text.isEmpty() ? -1 : School.findSchoolIdByName(text);
                                currentSubstitutionDay.setSchool(id);
                                break;
                            case "datum":
                                long updated = dateTimeFormatterKomma.parse(text).getTime();
                                currentSubstitutionDay.setUpdated(updated);
                                break;
                            // all data that is actual substitution information
                            case "klasse":
                                String course = "";

                                if (text.length() == 9 || text.length() > 10) {
                                    String[] rangeClasses = {text.substring(0, 4), text.substring(5, 9)};
                                    currentSubstitution.setClassYearLetter(rangeClasses[0]);
                                    String[] rangeClassesLetter = {rangeClasses[0].substring(3, 4), rangeClasses[1].substring(3, 4)};
                                    multipleClasses = (int) rangeClassesLetter[1].charAt(0) - (int) rangeClassesLetter[0].charAt(0);
                                    currentSubstitution.setClassYearLetter(rangeClasses[0]);
                                    if (text.length() > 10) {
                                        course = text.substring(11);
                                    }
                                } else {
                                    if (text.length() == 10) {
                                        course = text.substring(6);
                                    }
                                    text = text.substring(0, 4);
                                    currentSubstitution.setClassYearLetter(text);
                                }
                                currentSubstitution.setClassCourse(course);
                                break;
                            case "stunde":
                                int periods = Integer.parseInt(text.replaceAll("-", ""));
                                if (String.valueOf(periods).length() > 1) {
                                    multiplePeriods = (periods % 10) - (periods / 10);
                                    periods /= 10;
                                }
                                currentSubstitution.setPeriod(periods);
                                break;
                            case "fach":
                                if (!text.equalsIgnoreCase("")) {
                                    currentSubstitution.setSubject(Subject.getSubjectIdBySubjectShort(text));
                                }
                                break;
                            case "lehrer":
                                if (!text.equalsIgnoreCase("")) {
                                    String teacherString = text.replaceAll("[()]", "");
                                    currentSubstitution.setTeacher(Teacher.getTeacherIdByTeacherShort(teacherString));
                                } else {
                                    currentSubstitution.setTeacher(-1);
                                }
                                break;
                            case "raum":
                                currentSubstitution.setRoom(text);
                                break;
                            case "info":
                                currentSubstitution.setInfo(text);
                                break;

                            case "aktion":
                                int letterNumber;
                                String initialLetter = currentSubstitution.getClassYearLetter();
                                int initialPeriod = currentSubstitution.getPeriod();
                                //Log.i(TAG, currentSubstitution.getClassYearLetter().substring(0, 2) + "-" + currentSubstitution.getClassCourse() + "-" + currentSubstitution.getPeriod() + "-" + currentSubstitution.getSubject() + "-" + currentSubstitution.getTeacher() + "-" + currentSubstitution.getRoom() + "-" + currentSubstitution.getInfo() + "-" + currentSubstitution.getChanges());
                                //Log.i(TAG, "mPeriods: " + multiplePeriods + " -- mClasses: " + multipleClasses);
                                //Log.i(TAG, currentSubstitution.getClassYearLetter() + "-" + currentSubstitution.getClassCourse() + "-" + currentSubstitution.getPeriod() + "-" + currentSubstitution.getSubject() + "-" + currentSubstitution.getTeacher() + "-" + currentSubstitution.getRoom() + "-" + currentSubstitution.getInfo() + "-" + currentSubstitution.getChanges());
                                for (int i = 0; i <= multiplePeriods; i++) {
                                    for (int j = 0; j <= multipleClasses; j++) {
                                        currentSubstitution.setPeriod(initialPeriod + i);
                                        letterNumber = initialLetter.charAt(3) + j;
                                        currentSubstitution.setClassYearLetter(initialLetter.replace(initialLetter.charAt(3), (char) letterNumber));
                                        currentSubstitutionList.add(currentSubstitution);
                                        Log.i(TAG, "Listgröße: " + currentSubstitutionList.size());
                                        //Log.i(TAG, currentSubstitution.getClassYearLetter() + "-" + currentSubstitution.getClassCourse() + "-" + currentSubstitution.getPeriod() + "-" + currentSubstitution.getSubject() + "-" + currentSubstitution.getTeacher() + "-" + currentSubstitution.getRoom() + "-" + currentSubstitution.getInfo() + "-" + currentSubstitution.getChanges());
                                    }
                                }

                                //Log.i(TAG, currentSubstitution.getClassYearLetter() + "-" + currentSubstitution.getClassCourse() + "-" + currentSubstitution.getPeriod() + "-" + currentSubstitution.getSubject() + "-" + currentSubstitution.getTeacher() + "-" + currentSubstitution.getRoom() + "-" + currentSubstitution.getInfo() + "-" + currentSubstitution.getChanges());
                                break;

                            case "haupt":
                                currentSubstitutionDay.setSubstitutionList(currentSubstitutionList);
                                Log.i(TAG, "Menge der Vertretungen nach dem Hinzufügen: " + currentSubstitutionList.size());
                                results.add(currentSubstitutionDay);
                                Log.i(TAG, "Menge der Vertretungen nach dem Hinzufügen(2): " + results.get(results.size()-1).getSubstitutionList().size());

                                break;
                        }
                        break;
                }
                eventType = xmlPullParser.next();
            }
        } catch (IOException | XmlPullParserException e) {
            Log.e(TAG, "Fehler beim Parsen/IO: ", e);
        } catch (ParseException e) {
            Log.e(TAG, "ParseException: ", e);
        } catch (IllegalFormatException e) {
            Log.e(TAG, "No school with this name found!", e);
        }
        for (int i = 0; i < results.size(); i++) {
            Log.i(TAG, "Datum: " + results.get(i).getDate() + "\nMenge der Vertretungen: " + results.get(i).getSubstitutionList().size());
        }
        Log.i(TAG, "finished parsing, result size: " + String.valueOf(results.size()));
        return results;
}