private Set<String> getHighlights(final ExpressionOperator expression,
                                      final DateTimeSettings dateTimeSettings) {
        Set<String> highlights = Collections.emptySet();

//        try {
//            // Create a map of index fields keyed by name.
//            final IndexFieldsMap indexFieldsMap = new IndexFieldsMap(index.getFields());
//            // Parse the query.
//            final SearchExpressionQueryBuilder searchExpressionQueryBuilder = new SearchExpressionQueryBuilder(
//                    wordListProvider, indexFieldsMap, maxBooleanClauseCount, dateTimeSettings, nowEpochMilli);
//            final SearchExpressionQuery query = searchExpressionQueryBuilder
//                    .buildQuery(LuceneVersionUtil.CURRENT_LUCENE_VERSION, expression);
//
//            highlights = query.getTerms();
//        } catch (final RuntimeException e) {
//            LOGGER.debug(e.getMessage(), e);
//        }

        return highlights;
    }
Compiles the query, extracts terms and then returns them for use in hit
highlighting.
stroom-analytics/stroom-analytics-impl/src/main/java/stroom/analytics/impl/AnalyticsSearchProvider.java