io.druid.indexing.overlord.autoscaling.ScalingStats Maven / Gradle / Ivy

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/*
 * Druid - a distributed column store.
 * Copyright 2012 - 2015 Metamarkets Group Inc.
 *
 * 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 io.druid.indexing.overlord.autoscaling;

import com.fasterxml.jackson.annotation.JsonProperty;
import com.fasterxml.jackson.annotation.JsonValue;
import com.google.common.collect.Lists;
import com.google.common.collect.MinMaxPriorityQueue;
import org.joda.time.DateTime;

import java.util.Collections;
import java.util.Comparator;
import java.util.List;

/**
 */
public class ScalingStats
{
  public static enum EVENT
  {
    PROVISION,
    TERMINATE
  }

  private static final Comparator comparator = new Comparator()
  {
    @Override
    public int compare(ScalingEvent s1, ScalingEvent s2)
    {
      return -s1.getTimestamp().compareTo(s2.getTimestamp());
    }
  };

  private final Object lock = new Object();

  private final MinMaxPriorityQueue recentEvents;

  public ScalingStats(int capacity)
  {
    if (capacity == 0) {
      this.recentEvents = MinMaxPriorityQueue.orderedBy(comparator).create();
    } else {
      this.recentEvents = MinMaxPriorityQueue
          .orderedBy(comparator)
          .maximumSize(capacity)
          .create();
    }
  }

  public void addProvisionEvent(AutoScalingData data)
  {
    synchronized (lock) {
      recentEvents.add(
          new ScalingEvent(
              data,
              new DateTime(),
              EVENT.PROVISION
          )
      );
    }
  }

  public void addTerminateEvent(AutoScalingData data)
  {
    synchronized (lock) {
      recentEvents.add(
          new ScalingEvent(
              data,
              new DateTime(),
              EVENT.TERMINATE
          )
      );
    }
  }

  @JsonValue
  public List toList()
  {
    synchronized (lock) {
      List retVal = Lists.newArrayList(recentEvents);
      Collections.sort(retVal, comparator);
      return retVal;
    }
  }

  public static class ScalingEvent
  {
    private final AutoScalingData data;
    private final DateTime timestamp;
    private final EVENT event;

    private ScalingEvent(
        AutoScalingData data,
        DateTime timestamp,
        EVENT event
    )
    {
      this.data = data;
      this.timestamp = timestamp;
      this.event = event;
    }

    @JsonProperty
    public AutoScalingData getData()
    {
      return data;
    }

    @JsonProperty
    public DateTime getTimestamp()
    {
      return timestamp;
    }

    @JsonProperty
    public EVENT getEvent()
    {
      return event;
    }

    @Override
    public String toString()
    {
      return "ScalingEvent{" +
             "data=" + data +
             ", timestamp=" + timestamp +
             ", event=" + event +
             '}';
    }
  }
}