public void test_getCrawlerDocumentSpaceCharsAsArray() {
        FessProp.propMap.clear();
        FessConfig fessConfig = new FessConfig.SimpleImpl() {
            @Override
            public String getCrawlerDocumentSpaceChars() {
                return "u0020u3000";
            }
        };

        int[] chars = fessConfig.getCrawlerDocumentSpaceCharsAsArray();
        assertEquals(2, chars.length);

        return requiredValidator.isValid(value, null);
    }

    String getCrawlerDocumentSpaceChars();

    default int[] getCrawlerDocumentSpaceCharsAsArray() {
        return getCrawlerDocumentCharsAsArray(CRAWLER_DOCUMENT_SPACE_CHARS, getCrawlerDocumentSpaceChars());
    }

    default String[] getCrawlerDocumentSpaces() {