(f, b) -> QueryBuilders.matchPhrasePrefixQuery(f, toLowercaseWildcard(text))
                            .boost(b * boost)
                            .maxExpansions(fessConfig.getQueryPrefixExpansionsAsInteger())
                            .slop(fessConfig.getQueryPrefixSlopAsInteger()));
        }

        if (!isSearchField(field)) {
            final String query = prefixQuery.getPrefix().toString();

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

    /**
     * Get the value for the key 'query.prefix.slop'. <br>
     * The value is, e.g. 0 <br>
     * comment: Slop value for prefix queries.