public synchronized void reset()

in java/client/src/main/java/org/apache/rocketmq/client/java/metrics/ClientMeterManager.java [81:173]
81 lines of code
9 McCabe index (conditional complexity)

    public synchronized void reset(Metric metric) {
        try {
            if (clientMeter.satisfy(metric)) {
                log.info("Metric settings is satisfied by the current message meter, metric={}, clientId={}",
                    metric, clientId);
                return;
            }
            if (!metric.isOn()) {
                log.info("Metric is off, clientId={}", clientId);
                clientMeter.shutdown();
                clientMeter = ClientMeter.disabledInstance(clientId);
                return;
            }
            final Endpoints endpoints = metric.getEndpoints();
            final NettyChannelBuilder channelBuilder = NettyChannelBuilder.forTarget(endpoints.getGrpcTarget())
                .intercept(new AuthInterceptor(clientConfiguration, clientId));

            if (clientConfiguration.isSslEnabled()) {
                final SslContextBuilder builder = GrpcSslContexts.forClient();
                builder.trustManager(InsecureTrustManagerFactory.INSTANCE);
                SslContext sslContext = builder.build();
                channelBuilder.sslContext(sslContext);
            } else {
                channelBuilder.usePlaintext();
            }

            final List<InetSocketAddress> socketAddresses = endpoints.toSocketAddresses();
            if (null != socketAddresses) {
                IpNameResolverFactory metricResolverFactory = new IpNameResolverFactory(socketAddresses);
                channelBuilder.nameResolverFactory(metricResolverFactory);
            }
            ManagedChannel channel = channelBuilder.build();
            OtlpGrpcMetricExporter exporter = OtlpGrpcMetricExporter.builder().setChannel(channel)
                .setTimeout(METRIC_EXPORTER_RPC_TIMEOUT)
                .build();

            InstrumentSelector sendSuccessCostTimeInstrumentSelector = InstrumentSelector.builder()
                .setType(InstrumentType.HISTOGRAM).setName(HistogramEnum.SEND_COST_TIME.getName()).build();
            final View sendSuccessCostTimeView = View.builder()
                .setAggregation(HistogramEnum.SEND_COST_TIME.getBucket()).build();

            InstrumentSelector deliveryLatencyInstrumentSelector = InstrumentSelector.builder()
                .setType(InstrumentType.HISTOGRAM).setName(HistogramEnum.DELIVERY_LATENCY.getName()).build();
            final View deliveryLatencyView = View.builder().setAggregation(HistogramEnum.DELIVERY_LATENCY.getBucket())
                .build();

            InstrumentSelector awaitTimeInstrumentSelector = InstrumentSelector.builder()
                .setType(InstrumentType.HISTOGRAM).setName(HistogramEnum.AWAIT_TIME.getName()).build();
            final View awaitTimeView = View.builder().setAggregation(HistogramEnum.AWAIT_TIME.getBucket()).build();

            InstrumentSelector processTimeInstrumentSelector = InstrumentSelector.builder()
                .setType(InstrumentType.HISTOGRAM).setName(HistogramEnum.PROCESS_TIME.getName()).build();
            final View processTimeView = View.builder().setAggregation(HistogramEnum.PROCESS_TIME.getBucket()).build();

            PeriodicMetricReader reader = PeriodicMetricReader.builder(exporter)
                .setInterval(METRIC_READER_INTERVAL).build();

            final SdkMeterProvider provider = SdkMeterProvider.builder()
                .setResource(Resource.empty())
                .registerMetricReader(reader)
                .registerView(sendSuccessCostTimeInstrumentSelector, sendSuccessCostTimeView)
                .registerView(deliveryLatencyInstrumentSelector, deliveryLatencyView)
                .registerView(awaitTimeInstrumentSelector, awaitTimeView)
                .registerView(processTimeInstrumentSelector, processTimeView)
                .build();

            final OpenTelemetrySdk openTelemetry = OpenTelemetrySdk.builder().setMeterProvider(provider).build();
            Meter meter = openTelemetry.getMeter(METRIC_INSTRUMENTATION_NAME);

            // Reset message meter.
            ClientMeter existedClientMeter = clientMeter;
            clientMeter = new ClientMeter(meter, endpoints, provider, clientId);
            existedClientMeter.shutdown();
            log.info("Metrics is on, endpoints={}, clientId={}", endpoints, clientId);

            final List<GaugeEnum> gauges = gaugeObserver.getGauges();
            for (GaugeEnum gauge : gauges) {
                meter.gaugeBuilder(gauge.getName()).buildWithCallback(measurement -> {
                    final Map<Attributes, Double> map = gaugeObserver.getValues(gauge);
                    if (map.isEmpty()) {
                        return;
                    }
                    for (Map.Entry<Attributes, Double> entry : map.entrySet()) {
                        final Attributes attributes = entry.getKey();
                        final Double value = entry.getValue();
                        measurement.record(value, attributes);
                    }
                });
            }
        } catch (Throwable t) {
            log.error("Exception raised when resetting message meter, clientId={}", clientId, t);
        }
    }