private static List parseStandardHeader()

in repository/service/src/main/java/org/apache/karaf/cave/repository/service/bundlerepository/ResourceBuilder.java [1005:1121]
113 lines of code
33 McCabe index (conditional complexity)

    private static List<ParsedHeaderClause> parseStandardHeader(String header) {
        List<ParsedHeaderClause> clauses = new ArrayList<>();
        if (header == null) {
            return clauses;
        }
        ParsedHeaderClause clause = null;
        String key = null;
        Map targetMap = null;
        int state = CLAUSE_START;
        int currentPosition = 0;
        int startPosition = 0;
        int length = header.length();
        boolean quoted = false;
        boolean escaped = false;

        char currentChar;
        do {
            currentChar = charAt(currentPosition, header, length);
            switch (state) {
                case CLAUSE_START:
                    clause = new ParsedHeaderClause();
                    clauses.add(clause);
                    // Fall through
                case PARAMETER_START:
                    startPosition = currentPosition;
                    state = KEY;
                    // Fall through
                case KEY:
                    switch (currentChar) {
                        case ':':
                        case '=':
                            key = header.substring(startPosition, currentPosition).trim();
                            startPosition = currentPosition + 1;
                            targetMap = clause.attrs;
                            state = currentChar == ':' ? DIRECTIVE_OR_TYPEDATTRIBUTE : ARGUMENT;
                            break;
                        case EOF:
                        case ',':
                        case ';':
                            clause.paths.add(header.substring(startPosition, currentPosition).trim());
                            state = currentChar == ',' ? CLAUSE_START : PARAMETER_START;
                            break;
                        default:
                            break;
                    }
                    currentPosition++;
                    break;
                case DIRECTIVE_OR_TYPEDATTRIBUTE:
                    switch (currentChar) {
                        case '=':
                            if (startPosition != currentPosition) {
                                clause.types.put(key, header.substring(startPosition, currentPosition).trim());
                            } else {
                                targetMap = clause.dirs;
                            }
                            state = ARGUMENT;
                            startPosition = currentPosition + 1;
                            break;
                        default:
                            break;
                    }
                    currentPosition++;
                    break;
                case ARGUMENT:
                    if (currentChar == '\"') {
                        quoted = true;
                        currentPosition++;
                    } else {
                        quoted = false;
                    }
                    if (!Character.isWhitespace(currentChar)) {
                        state = VALUE;
                    } else {
                        currentPosition++;
                    }
                    break;
                case VALUE:
                    if (escaped) {
                        escaped = false;
                    } else {
                        if (currentChar == '\\') {
                            escaped = true;
                        } else if (quoted && currentChar == '\"') {
                            quoted = false;
                        } else if (!quoted) {
                            String value;
                            switch (currentChar) {
                                case EOF:
                                case ';':
                                case ',':
                                    value = header.substring(startPosition, currentPosition).trim();
                                    if (value.startsWith("\"") && value.endsWith("\"")) {
                                        value = value.substring(1, value.length() - 1);
                                    }
                                    if (targetMap.put(key, value) != null) {
                                        throw new IllegalArgumentException(
                                                "Duplicate '" + key + "' in: " + header);
                                    }
                                    state = currentChar == ';' ? PARAMETER_START : CLAUSE_START;
                                    break;
                                default:
                                    break;
                            }
                        }
                    }
                    currentPosition++;
                    break;
                default:
                    break;
            }
        } while (currentChar != EOF);

        if (state > PARAMETER_START) {
            throw new IllegalArgumentException("Unable to parse header: " + header);
        }
        return clauses;
    }