content: /**
   * Licensed 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.aurora.scheduler.testing;
  
  import java.util.Map;
  import java.util.concurrent.atomic.AtomicLong;
  import java.util.function.Supplier;
  
  import com.google.common.collect.ImmutableMap;
  import com.google.common.collect.Maps;
  
  import org.apache.aurora.common.stats.Stat;
  import org.apache.aurora.common.stats.StatsProvider;
  
  /**
   * A fake stats provider for use in testing.
   */
  public class FakeStatsProvider implements StatsProvider {
    private final Map<String, Supplier<? extends Number>> stats = Maps.newHashMap();
  
    /**
     * Gets the current value of a stat.
     *
     * @param statName Name of the stat to fetch.
     * @return Current stat value.
     */
    public Number getValue(String statName) {
      return stats.get(statName).get();
    }
  
    /**
     * Gets the current values of all exported stats.
     *
     * @return All exported stat names and their associated values.
     */
    public Map<String, ? extends Number> getAllValues() {
      return ImmutableMap.copyOf(Maps.transformValues(
          stats,
          Supplier::get));
    }
  
    /**
     * Gets the value of a stat as a long.
     *
     * @param name Stat name.
     * @return Value, as a long.
     */
    public long getLongValue(String name) {
      return stats.get(name).get().longValue();
    }
  
    @Override
    public AtomicLong makeCounter(String name) {
      final AtomicLong counter = new AtomicLong();
      stats.put(name, counter::get);
      return counter;
    }
  
    @Override
    public <T extends Number> Stat<T> makeGauge(String name, Supplier<T> gauge) {
      stats.put(name, gauge);
  
      return new Stat<T>() {
        @Override
        public String getName() {
          return name;
        }
  
        @Override
        public T read() {
          return gauge.get();
        }
      };
    }
  
    @Override
    public StatsProvider untracked() {
      return this;
    }
  
    @Override
    public RequestTimer makeRequestTimer(String name) {
      throw new UnsupportedOperationException();
    }
  }
  