* Gets the number of shards for the data index.
     *
     * @return the number of data shards
     */
    @Override
    public int getDataShards() {
        return ComponentUtil.getFessConfig().getIndexDocumentCrawlerDataNumberOfShardsAsInteger();
    }

    /**
     * Gets the number of shards for the filter index.
     *
     * @return the number of filter shards
     */
    @Override
    public int getFilterShards() {

     * @return The value of found property. (NotNull: if not found, exception but basically no way)
     * @throws NumberFormatException When the property is not integer.
     */
    Integer getIndexDocumentCrawlerDataNumberOfShardsAsInteger();

    /**
     * Get the value for the key 'index.document.crawler.filter.number_of_shards'. <br>
     * The value is, e.g. 10 <br>