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.beam.runners.flink.metrics;
  
  import java.util.Objects;
  import org.apache.flink.metrics.Counter;
  import org.apache.flink.metrics.Gauge;
  import org.apache.flink.metrics.Histogram;
  import org.apache.flink.metrics.HistogramStatistics;
  import org.apache.flink.metrics.Meter;
  import org.apache.flink.metrics.Metric;
  
  /** Helper for pretty-printing {@link Metric Flink metrics}. */
  public class Metrics {
    public static String toString(Metric metric) {
      if (metric instanceof Counter) {
        return Long.toString(((Counter) metric).getCount());
      } else if (metric instanceof Gauge) {
        return Objects.toString(((Gauge<?>) metric).getValue());
      } else if (metric instanceof Meter) {
        return Double.toString(((Meter) metric).getRate());
      } else if (metric instanceof Histogram) {
        HistogramStatistics stats = ((Histogram) metric).getStatistics();
        return String.format(
            "count=%d, min=%d, max=%d, mean=%f, stddev=%f, p50=%f, p75=%f, p95=%f",
            stats.size(),
            stats.getMin(),
            stats.getMax(),
            stats.getMean(),
            stats.getStdDev(),
            stats.getQuantile(0.5),
            stats.getQuantile(0.75),
            stats.getQuantile(0.95));
      } else {
        throw new IllegalStateException(
            String.format(
                "Cannot remove unknown metric type %s. This indicates that the reporter "
                    + "does not support this metric type.",
                metric.getClass().getName()));
      }
    }
  }
  