if (logger.isDebugEnabled()) {
            logger.debug("Initialize {}", this.getClass().getSimpleName());
        }
        fessConfig = ComponentUtil.getFessConfig();
        split(fessConfig.getSuggestFieldContents(), ",")
                .of(stream -> stream.filter(StringUtil::isNotBlank).forEach(contentFieldNameSet::add));

    }

    // Mock classes
    private static class MockFessConfig extends FessConfig.SimpleImpl {
        private static final long serialVersionUID = 1L;

        @Override
        public String getSuggestFieldContents() {
            return "title,content";
        }

        @Override
        public String getSuggestFieldTags() {
            return "label";
        }

        @Override