processing/src/main/java/io/druid/query/timeboundary/TimeBoundaryQueryQueryToolChest.java

/*
 * Druid - a distributed column store.
 * Copyright (C) 2012, 2013  Metamarkets Group Inc.
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * as published by the Free Software Foundation; either version 2
 * of the License, or (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
 */

package io.druid.query.timeboundary;

import com.fasterxml.jackson.core.type.TypeReference;
import com.google.common.base.Function;
import com.google.common.base.Functions;
import com.google.common.base.Predicate;
import com.google.common.collect.Iterables;
import com.google.common.collect.Lists;
import com.google.common.collect.Ordering;
import com.metamx.common.guava.MergeSequence;
import com.metamx.common.guava.Sequence;
import com.metamx.common.guava.Sequences;
import com.metamx.emitter.service.ServiceMetricEvent;
import io.druid.collections.OrderedMergeSequence;
import io.druid.query.BySegmentSkippingQueryRunner;
import io.druid.query.CacheStrategy;
import io.druid.query.DataSourceUtil;
import io.druid.query.Query;
import io.druid.query.QueryRunner;
import io.druid.query.QueryToolChest;
import io.druid.query.Result;
import io.druid.query.aggregation.MetricManipulationFn;
import io.druid.timeline.LogicalSegment;
import org.joda.time.DateTime;

import javax.annotation.Nullable;
import java.nio.ByteBuffer;
import java.util.List;

/**
 */
public class TimeBoundaryQueryQueryToolChest
    extends QueryToolChest<Result<TimeBoundaryResultValue>, TimeBoundaryQuery>
{
  private static final byte TIMEBOUNDARY_QUERY = 0x3;

  private static final TypeReference<Result<TimeBoundaryResultValue>> TYPE_REFERENCE = new TypeReference<Result<TimeBoundaryResultValue>>()
  {
  };
  private static final TypeReference<Object> OBJECT_TYPE_REFERENCE = new TypeReference<Object>()
  {
  };

  @Override
  public <T extends LogicalSegment> List<T> filterSegments(TimeBoundaryQuery query, List<T> segments)
  {
    if (segments.size() <= 1) {
      return segments;
    }

    final T min = segments.get(0);
    final T max = segments.get(segments.size() - 1);

    return Lists.newArrayList(
        Iterables.filter(
            segments,
            new Predicate<T>()
            {
              @Override
              public boolean apply(T input)
              {
                return (min != null && input.getInterval().overlaps(min.getInterval())) ||
                       (max != null && input.getInterval().overlaps(max.getInterval()));
              }
            }
        )
    );
  }

  @Override
  public QueryRunner<Result<TimeBoundaryResultValue>> mergeResults(
      final QueryRunner<Result<TimeBoundaryResultValue>> runner
  )
  {
    return new BySegmentSkippingQueryRunner<Result<TimeBoundaryResultValue>>(runner)
    {
      @Override
      protected Sequence<Result<TimeBoundaryResultValue>> doRun(
          QueryRunner<Result<TimeBoundaryResultValue>> baseRunner, Query<Result<TimeBoundaryResultValue>> input
      )
      {
        TimeBoundaryQuery query = (TimeBoundaryQuery) input;
        return Sequences.simple(
            query.mergeResults(
                Sequences.toList(baseRunner.run(query), Lists.<Result<TimeBoundaryResultValue>>newArrayList())
            )
        );
      }
    };
  }

  @Override
  public Sequence<Result<TimeBoundaryResultValue>> mergeSequences(Sequence<Sequence<Result<TimeBoundaryResultValue>>> seqOfSequences)
  {
    return new OrderedMergeSequence<>(getOrdering(), seqOfSequences);
  }

  @Override
  public ServiceMetricEvent.Builder makeMetricBuilder(TimeBoundaryQuery query)
  {
    return new ServiceMetricEvent.Builder()
        .setUser2(DataSourceUtil.getMetricName(query.getDataSource()))
        .setUser4(query.getType())
        .setUser6("false");
  }

  @Override
  public Function<Result<TimeBoundaryResultValue>, Result<TimeBoundaryResultValue>> makePreComputeManipulatorFn(
      TimeBoundaryQuery query, MetricManipulationFn fn
  )
  {
    return Functions.identity();
  }

  @Override
  public TypeReference<Result<TimeBoundaryResultValue>> getResultTypeReference()
  {
    return TYPE_REFERENCE;
  }

  @Override
  public CacheStrategy<Result<TimeBoundaryResultValue>, Object, TimeBoundaryQuery> getCacheStrategy(TimeBoundaryQuery query)
  {
    return new CacheStrategy<Result<TimeBoundaryResultValue>, Object, TimeBoundaryQuery>()
    {
      @Override
      public byte[] computeCacheKey(TimeBoundaryQuery query)
      {
        final byte[] cacheKey = query.getCacheKey();
        return ByteBuffer.allocate(1 + cacheKey.length)
                         .put(TIMEBOUNDARY_QUERY)
                         .put(cacheKey)
                         .array();
      }

      @Override
      public TypeReference<Object> getCacheObjectClazz()
      {
        return OBJECT_TYPE_REFERENCE;
      }

      @Override
      public Function<Result<TimeBoundaryResultValue>, Object> prepareForCache()
      {
        return new Function<Result<TimeBoundaryResultValue>, Object>()
        {
          @Override
          public Object apply(Result<TimeBoundaryResultValue> input)
          {
            return Lists.newArrayList(input.getTimestamp().getMillis(), input.getValue());
          }
        };
      }

      @Override
      public Function<Object, Result<TimeBoundaryResultValue>> pullFromCache()
      {
        return new Function<Object, Result<TimeBoundaryResultValue>>()
        {
          @Override
          @SuppressWarnings("unchecked")
          public Result<TimeBoundaryResultValue> apply(Object input)
          {
            List<Object> result = (List<Object>) input;

            return new Result<>(
                new DateTime(result.get(0)),
                new TimeBoundaryResultValue(result.get(1))
            );
          }
        };
      }

      @Override
      public Sequence<Result<TimeBoundaryResultValue>> mergeSequences(Sequence<Sequence<Result<TimeBoundaryResultValue>>> seqOfSequences)
      {
        return new MergeSequence<>(getOrdering(), seqOfSequences);
      }
    };
  }

  public Ordering<Result<TimeBoundaryResultValue>> getOrdering()
  {
    return Ordering.natural();
  }
}