content: /*
   * Licensed to the Apache Software Foundation (ASF) under one
   * or more contributor license agreements.  See the NOTICE file
   * distributed with this work for additional information
   * regarding copyright ownership.  The ASF licenses this file
   * to you under the Apache License, Version 2.0 (the
   * "License"); you may not use this file except in compliance
   * with the License.  You may obtain a copy of the License at
   *
   *     http://www.apache.org/licenses/LICENSE-2.0
   *
   * Unless required by applicable law or agreed to in writing, software
   * distributed under the License is distributed on an "AS IS" BASIS,
   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   * See the License for the specific language governing permissions and
   * limitations under the License.
   */
  package com.datastax.oss.driver.internal.core.metrics;
  
  import com.codahale.metrics.Counter;
  import com.codahale.metrics.Histogram;
  import com.codahale.metrics.Meter;
  import com.codahale.metrics.Metric;
  import com.codahale.metrics.MetricRegistry;
  import com.codahale.metrics.Reservoir;
  import com.codahale.metrics.Timer;
  import com.datastax.oss.driver.api.core.config.DriverExecutionProfile;
  import com.datastax.oss.driver.api.core.config.DriverOption;
  import com.datastax.oss.driver.internal.core.context.InternalDriverContext;
  import edu.umd.cs.findbugs.annotations.Nullable;
  import java.time.Duration;
  import java.util.Set;
  import java.util.concurrent.ConcurrentHashMap;
  import java.util.concurrent.ConcurrentMap;
  import java.util.concurrent.TimeUnit;
  import java.util.function.Supplier;
  import net.jcip.annotations.ThreadSafe;
  import org.slf4j.Logger;
  import org.slf4j.LoggerFactory;
  
  @ThreadSafe
  public abstract class DropwizardMetricUpdater<MetricT> extends AbstractMetricUpdater<MetricT> {
  
    private static final Logger LOG = LoggerFactory.getLogger(DropwizardMetricUpdater.class);
  
    protected final MetricRegistry registry;
  
    protected final ConcurrentMap<MetricT, Metric> metrics = new ConcurrentHashMap<>();
  
    protected final ConcurrentMap<MetricT, Reservoir> reservoirs = new ConcurrentHashMap<>();
  
    protected DropwizardMetricUpdater(
        InternalDriverContext context, Set<MetricT> enabledMetrics, MetricRegistry registry) {
      super(context, enabledMetrics);
      this.registry = registry;
    }
  
    @SuppressWarnings({"unchecked", "TypeParameterUnusedInFormals"})
    public <T extends Metric> T getMetric(
        MetricT metric, @SuppressWarnings("unused") String profileName) {
      return (T) metrics.get(metric);
    }
  
    @Override
    public void incrementCounter(MetricT metric, @Nullable String profileName, long amount) {
      if (isEnabled(metric, profileName)) {
        getOrCreateCounterFor(metric).inc(amount);
      }
    }
  
    @Override
    public void updateHistogram(MetricT metric, @Nullable String profileName, long value) {
      if (isEnabled(metric, profileName)) {
        getOrCreateHistogramFor(metric).update(value);
      }
    }
  
    @Override
    public void markMeter(MetricT metric, @Nullable String profileName, long amount) {
      if (isEnabled(metric, profileName)) {
        getOrCreateMeterFor(metric).mark(amount);
      }
    }
  
    @Override
    public void updateTimer(
        MetricT metric, @Nullable String profileName, long duration, TimeUnit unit) {
      if (isEnabled(metric, profileName)) {
        getOrCreateTimerFor(metric).update(duration, unit);
      }
    }
  
    @Override
    public void clearMetrics() {
      for (MetricT metric : metrics.keySet()) {
        MetricId id = getMetricId(metric);
        registry.remove(id.getName());
      }
      metrics.clear();
      reservoirs.clear();
    }
  
    protected abstract MetricId getMetricId(MetricT metric);
  
    protected void initializeGauge(
        MetricT metric, DriverExecutionProfile profile, Supplier<Number> supplier) {
      if (isEnabled(metric, profile.getName())) {
        metrics.computeIfAbsent(
            metric,
            m -> {
              MetricId id = getMetricId(m);
              return registry.gauge(id.getName(), () -> supplier::get);
            });
      }
    }
  
    protected void initializeCounter(MetricT metric, DriverExecutionProfile profile) {
      if (isEnabled(metric, profile.getName())) {
        getOrCreateCounterFor(metric);
      }
    }
  
    protected void initializeHdrTimer(
        MetricT metric,
        DriverExecutionProfile profile,
        DriverOption highestLatency,
        DriverOption significantDigits,
        DriverOption interval) {
      if (isEnabled(metric, profile.getName())) {
        reservoirs.computeIfAbsent(
            metric, m -> createHdrReservoir(m, profile, highestLatency, significantDigits, interval));
        getOrCreateTimerFor(metric);
      }
    }
  
    protected Counter getOrCreateCounterFor(MetricT metric) {
      return (Counter)
          metrics.computeIfAbsent(
              metric,
              m -> {
                MetricId id = getMetricId(m);
                return registry.counter(id.getName());
              });
    }
  
    protected Meter getOrCreateMeterFor(MetricT metric) {
      return (Meter)
          metrics.computeIfAbsent(
              metric,
              m -> {
                MetricId id = getMetricId(m);
                return registry.meter(id.getName());
              });
    }
  
    protected Histogram getOrCreateHistogramFor(MetricT metric) {
      return (Histogram)
          metrics.computeIfAbsent(
              metric,
              m -> {
                MetricId id = getMetricId(m);
                return registry.histogram(id.getName());
              });
    }
  
    protected Timer getOrCreateTimerFor(MetricT metric) {
      return (Timer)
          metrics.computeIfAbsent(
              metric,
              m -> {
                MetricId id = getMetricId(m);
                Reservoir reservoir = reservoirs.get(metric);
                Timer timer = reservoir == null ? new Timer() : new Timer(reservoir);
                return registry.timer(id.getName(), () -> timer);
              });
    }
  
    protected HdrReservoir createHdrReservoir(
        MetricT metric,
        DriverExecutionProfile profile,
        DriverOption highestLatencyOption,
        DriverOption significantDigitsOption,
        DriverOption intervalOption) {
      MetricId id = getMetricId(metric);
      Duration highestLatency = profile.getDuration(highestLatencyOption);
      int significantDigits = profile.getInt(significantDigitsOption);
      if (significantDigits < 0 || significantDigits > 5) {
        LOG.warn(
            "[{}] Configuration option {} is out of range (expected between 0 and 5, "
                + "found {}); using 3 instead.",
            id.getName(),
            significantDigitsOption,
            significantDigits);
        significantDigits = 3;
      }
      Duration refreshInterval = profile.getDuration(intervalOption);
      return new HdrReservoir(highestLatency, significantDigits, refreshInterval, id.getName());
    }
  }
  