protected Optional modifyEntry()

in apache-rat-core/src/main/java/org/apache/rat/config/exclusion/fileProcessors/GitIgnoreBuilder.java [67:104]
29 lines of code
11 McCabe index (conditional complexity)

    protected Optional<String> modifyEntry(final Consumer<MatcherSet> matcherSetConsumer, final DocumentName documentName, final String entry) {
        // An optional prefix "!" which negates the pattern;
        boolean prefix = entry.startsWith(NEGATION_PREFIX);
        String pattern = prefix || entry.startsWith(ESCAPED_COMMENT) || entry.startsWith(ESCAPED_NEGATION) ?
                entry.substring(1) : entry;

        // If there is a separator at the beginning or middle (or both) of the pattern, then
        // the pattern is relative to the directory level of the particular .gitignore file itself.
        // Otherwise, the pattern may also match at any level below the .gitignore level.
        int slashPos = pattern.indexOf(SLASH);
        // no slash or at end already
        if (slashPos == -1 || slashPos == pattern.length() - 1) {
            pattern = "**/" + pattern;
        }
        if (slashPos == 0) {
            pattern = pattern.substring(1);
        }
        // If there is a separator at the end of the pattern then the pattern will only match directories,
        // otherwise the pattern can match both files and directories.
        if (pattern.endsWith(SLASH)) {
            pattern = pattern.substring(0, pattern.length() - 1);
            String name = prefix ? NEGATION_PREFIX + pattern : pattern;
            DocumentName matcherPattern = DocumentName.builder(documentName).setName(name.replace(SLASH, documentName.getDirectorySeparator()))
                    .build();
            DocumentNameMatcher matcher = DocumentNameMatcher.and(new DocumentNameMatcher("isDirectory", File::isDirectory),
                    new DocumentNameMatcher(name, MatchPatterns.from(matcherPattern.localized(documentName.getDirectorySeparator()))));

            MatcherSet.Builder builder = new MatcherSet.Builder();
            if (prefix) {
                builder.addIncluded(matcher);
            } else {
                builder.addExcluded(matcher);
            }
            matcherSetConsumer.accept(builder.build());
            return Optional.empty();
        }
        return Optional.of(prefix ? NEGATION_PREFIX + pattern : pattern);
    }