geode-core/src/main/java/org/apache/geode/metrics/internal/NoopMeterRegistry.java

/*
 * 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.geode.metrics.internal;

import java.util.concurrent.TimeUnit;
import java.util.function.ToDoubleFunction;
import java.util.function.ToLongFunction;

import io.micrometer.core.instrument.Clock;
import io.micrometer.core.instrument.Counter;
import io.micrometer.core.instrument.DistributionSummary;
import io.micrometer.core.instrument.FunctionCounter;
import io.micrometer.core.instrument.FunctionTimer;
import io.micrometer.core.instrument.Gauge;
import io.micrometer.core.instrument.LongTaskTimer;
import io.micrometer.core.instrument.Measurement;
import io.micrometer.core.instrument.Meter;
import io.micrometer.core.instrument.MeterRegistry;
import io.micrometer.core.instrument.Timer;
import io.micrometer.core.instrument.distribution.DistributionStatisticConfig;
import io.micrometer.core.instrument.distribution.pause.PauseDetector;
import io.micrometer.core.instrument.noop.NoopCounter;
import io.micrometer.core.instrument.noop.NoopDistributionSummary;
import io.micrometer.core.instrument.noop.NoopFunctionCounter;
import io.micrometer.core.instrument.noop.NoopFunctionTimer;
import io.micrometer.core.instrument.noop.NoopGauge;
import io.micrometer.core.instrument.noop.NoopLongTaskTimer;
import io.micrometer.core.instrument.noop.NoopMeter;
import io.micrometer.core.instrument.noop.NoopTimer;
import io.micrometer.core.lang.NonNullApi;
import io.micrometer.core.lang.Nullable;

import org.apache.geode.annotations.Immutable;
import org.apache.geode.annotations.VisibleForTesting;

@NonNullApi
public class NoopMeterRegistry extends MeterRegistry {

  @Immutable
  @VisibleForTesting
  static final Clock NOOP_CLOCK = new Clock() {
    @Override
    public long wallTime() {
      return 0;
    }

    @Override
    public long monotonicTime() {
      return 0;
    }
  };

  public NoopMeterRegistry() {
    this(NOOP_CLOCK);
  }

  private NoopMeterRegistry(Clock clock) {
    super(clock);
  }

  @Override
  protected <T> Gauge newGauge(Meter.Id id, @Nullable T obj, ToDoubleFunction<T> valueFunction) {
    return new NoopGauge(id);
  }

  @Override
  protected Counter newCounter(Meter.Id id) {
    return new NoopCounter(id);
  }

  @Override
  protected LongTaskTimer newLongTaskTimer(Meter.Id id) {
    return new NoopLongTaskTimer(id);
  }

  @Override
  protected Timer newTimer(Meter.Id id, DistributionStatisticConfig distributionStatisticConfig,
      PauseDetector pauseDetector) {
    return new NoopTimer(id);
  }

  @Override
  protected DistributionSummary newDistributionSummary(Meter.Id id,
      DistributionStatisticConfig distributionStatisticConfig, double scale) {
    return new NoopDistributionSummary(id);
  }

  @Override
  protected Meter newMeter(Meter.Id id, Meter.Type type, Iterable<Measurement> measurements) {
    return new NoopMeter(id);
  }

  @Override
  protected <T> FunctionTimer newFunctionTimer(Meter.Id id, T obj, ToLongFunction<T> countFunction,
      ToDoubleFunction<T> totalTimeFunction, TimeUnit totalTimeFunctionUnit) {
    return new NoopFunctionTimer(id);
  }

  @Override
  protected <T> FunctionCounter newFunctionCounter(Meter.Id id, T obj,
      ToDoubleFunction<T> countFunction) {
    return new NoopFunctionCounter(id);
  }

  @Override
  protected TimeUnit getBaseTimeUnit() {
    return TimeUnit.SECONDS;
  }

  @Override
  protected DistributionStatisticConfig defaultHistogramConfig() {
    return DistributionStatisticConfig.NONE;
  }
}