final SystemHelper systemHelper = ComponentUtil.getSystemHelper();
        final Map<String, List<LogNotificationEvent>> eventsByLevel =
                events.stream().collect(Collectors.groupingBy(LogNotificationEvent::getLevel));

        for (final Map.Entry<String, List<LogNotificationEvent>> entry : eventsByLevel.entrySet()) {
            final String level = entry.getKey();

                            .collect(Collectors.groupingBy(Pair::getFirst, Collectors.mapping(Pair::getSecond, Collectors.toList())));
                    appendJson("search-field", searchFieldMap, buf).append(',');
                    final Map<String, List<String>> requestHeaderMap = entity.getRequestHeaderList()
                            .stream()

                    context.addQuery(boolQuery -> boolQuery.filter(geoInfo.toQueryBuilder()));
                }
            });
        }

        /**
         * Gets the collapse builder for result grouping.
         *
         * @param fessConfig the Fess configuration
         * @return the collapse builder
         */
        protected CollapseBuilder getCollapseBuilder(final FessConfig fessConfig) {

### Bug or Regression

Repetition  = "{" Expression "}" .
</pre>

<p>
Productions are expressions constructed from terms and the following
operators, in increasing precedence:
</p>
<pre class="grammar">
|   alternation
()  grouping
[]  option (0 or 1 times)
{}  repetition (0 to n times)
</pre>

<p>
Lowercase production names are used to identify lexical (terminal) tokens.
Non-terminals are in CamelCase. Lexical tokens are enclosed in