public static final String getDateTimePattern()

in src/main/core-api/java/com/mysql/cj/util/TimeUtil.java [371:530]
123 lines of code
37 McCabe index (conditional complexity)

    public static final String getDateTimePattern(String dt, boolean toTime) throws IOException {
        //
        // Special case
        //
        int dtLength = (dt != null) ? dt.length() : 0;

        if ((dtLength >= 8) && (dtLength <= 10)) {
            int dashCount = 0;
            boolean isDateOnly = true;

            for (int i = 0; i < dtLength; i++) {
                char c = dt.charAt(i);

                if (!Character.isDigit(c) && (c != '-')) {
                    isDateOnly = false;

                    break;
                }

                if (c == '-') {
                    dashCount++;
                }
            }

            if (isDateOnly && (dashCount == 2)) {
                return "yyyy-MM-dd";
            }
        }

        //
        // Special case - time-only
        //
        boolean colonsOnly = true;

        for (int i = 0; i < dtLength; i++) {
            char c = dt.charAt(i);

            if (!Character.isDigit(c) && (c != ':')) {
                colonsOnly = false;

                break;
            }
        }

        if (colonsOnly) {
            return "HH:mm:ss";
        }

        int n;
        int z;
        int count;
        int maxvecs;
        char c;
        char separator;
        StringReader reader = new StringReader(dt + " ");
        ArrayList<Object[]> vec = new ArrayList<>();
        ArrayList<Object[]> vecRemovelist = new ArrayList<>();
        Object[] nv = new Object[3];
        Object[] v;
        nv[0] = Character.valueOf('y');
        nv[1] = new StringBuilder();
        nv[2] = Integer.valueOf(0);
        vec.add(nv);

        if (toTime) {
            nv = new Object[3];
            nv[0] = Character.valueOf('h');
            nv[1] = new StringBuilder();
            nv[2] = Integer.valueOf(0);
            vec.add(nv);
        }

        while ((z = reader.read()) != -1) {
            separator = (char) z;
            maxvecs = vec.size();

            for (count = 0; count < maxvecs; count++) {
                v = vec.get(count);
                n = ((Integer) v[2]).intValue();
                c = getSuccessor(((Character) v[0]).charValue(), n);

                if (!Character.isLetterOrDigit(separator)) {
                    if ((c == ((Character) v[0]).charValue()) && (c != 'S')) {
                        vecRemovelist.add(v);
                    } else {
                        ((StringBuilder) v[1]).append(separator);

                        if ((c == 'X') || (c == 'Y')) {
                            v[2] = Integer.valueOf(4);
                        }
                    }
                } else {
                    if (c == 'X') {
                        c = 'y';
                        nv = new Object[3];
                        nv[1] = (new StringBuilder(((StringBuilder) v[1]).toString())).append('M');
                        nv[0] = Character.valueOf('M');
                        nv[2] = Integer.valueOf(1);
                        vec.add(nv);
                    } else if (c == 'Y') {
                        c = 'M';
                        nv = new Object[3];
                        nv[1] = (new StringBuilder(((StringBuilder) v[1]).toString())).append('d');
                        nv[0] = Character.valueOf('d');
                        nv[2] = Integer.valueOf(1);
                        vec.add(nv);
                    }

                    ((StringBuilder) v[1]).append(c);

                    if (c == ((Character) v[0]).charValue()) {
                        v[2] = Integer.valueOf(n + 1);
                    } else {
                        v[0] = Character.valueOf(c);
                        v[2] = Integer.valueOf(1);
                    }
                }
            }

            int size = vecRemovelist.size();

            for (int i = 0; i < size; i++) {
                v = vecRemovelist.get(i);
                vec.remove(v);
            }

            vecRemovelist.clear();
        }

        int size = vec.size();

        for (int i = 0; i < size; i++) {
            v = vec.get(i);
            c = ((Character) v[0]).charValue();
            n = ((Integer) v[2]).intValue();

            boolean bk = getSuccessor(c, n) != c;
            boolean atEnd = (((c == 's') || (c == 'm') || ((c == 'h') && toTime)) && bk);
            boolean finishesAtDate = (bk && (c == 'd') && !toTime);
            boolean containsEnd = (((StringBuilder) v[1]).toString().indexOf('W') != -1);

            if ((!atEnd && !finishesAtDate) || (containsEnd)) {
                vecRemovelist.add(v);
            }
        }

        size = vecRemovelist.size();

        for (int i = 0; i < size; i++) {
            vec.remove(vecRemovelist.get(i));
        }

        vecRemovelist.clear();
        v = vec.get(0); // might throw exception

        StringBuilder format = (StringBuilder) v[1];
        format.setLength(format.length() - 1);

        return format.toString();
    }