public StringFormatGroup.FormatResult format(String service, String endpointName) {
        final StringFormatGroup stringFormatGroup = rules.get(service);
        if (stringFormatGroup != null) {
            return stringFormatGroup.format(endpointName);
        } else {
            return new StringFormatGroup.FormatResult(false, endpointName, endpointName);
        }
    }
@param service      of the given endpoint belonged.
@param endpointName to do group checking.
@return group result and new endpoint name if rule matched.
oap-server/server-core/src/main/java/org/apache/skywalking/oap/server/core/config/group/EndpointGroupingRule.java