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 org.apache.kafka.common.metrics.stats;
  
  import org.apache.kafka.common.MetricName;
  import org.apache.kafka.common.metrics.CompoundStat;
  import org.apache.kafka.common.metrics.MetricConfig;
  
  import java.util.Arrays;
  import java.util.List;
  import java.util.concurrent.TimeUnit;
  
  
  /**
   * A compound stat that includes a rate metric and a cumulative total metric.
   */
  public class Meter implements CompoundStat {
      private final MetricName rateMetricName;
      private final MetricName totalMetricName;
      private final Rate rate;
      private final CumulativeSum total;
  
      /**
       * Construct a Meter with seconds as time unit
       */
      public Meter(MetricName rateMetricName, MetricName totalMetricName) {
          this(TimeUnit.SECONDS, new WindowedSum(), rateMetricName, totalMetricName);
      }
  
      /**
       * Construct a Meter with provided time unit
       */
      public Meter(TimeUnit unit, MetricName rateMetricName, MetricName totalMetricName) {
          this(unit, new WindowedSum(), rateMetricName, totalMetricName);
      }
  
      /**
       * Construct a Meter with seconds as time unit
       */
      public Meter(SampledStat rateStat, MetricName rateMetricName, MetricName totalMetricName) {
          this(TimeUnit.SECONDS, rateStat, rateMetricName, totalMetricName);
      }
  
      /**
       * Construct a Meter with provided time unit
       */
      public Meter(TimeUnit unit, SampledStat rateStat, MetricName rateMetricName, MetricName totalMetricName) {
          if (!(rateStat instanceof WindowedSum)) {
              throw new IllegalArgumentException("Meter is supported only for WindowedCount or WindowedSum.");
          }
          this.total = new CumulativeSum();
          this.rate = new Rate(unit, rateStat);
          this.rateMetricName = rateMetricName;
          this.totalMetricName = totalMetricName;
      }
  
      @Override
      public List<NamedMeasurable> stats() {
          return Arrays.asList(
              new NamedMeasurable(totalMetricName, total),
              new NamedMeasurable(rateMetricName, rate));
      }
  
      @Override
      public void record(MetricConfig config, double value, long timeMs) {
          rate.record(config, value, timeMs);
          // Total metrics with Count stat should record 1.0 (as recorded in the count)
          double totalValue = (rate.stat instanceof WindowedCount) ? 1.0 : value;
          total.record(config, totalValue, timeMs);
      }
  
      @Override
      public String toString() {
          return "Meter(" +
              "rate=" + rate +
              ", total=" + total +
              ", rateMetricName=" + rateMetricName +
              ", totalMetricName=" + totalMetricName +
              ')';
      }
  }
  