io.druid.query.aggregation.histogram.ApproximateHistogramFoldingSerde 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.query.aggregation.histogram;

import com.google.common.collect.Ordering;
import io.druid.data.input.InputRow;
import io.druid.segment.column.ColumnBuilder;
import io.druid.segment.data.GenericIndexed;
import io.druid.segment.data.ObjectStrategy;
import io.druid.segment.serde.ColumnPartSerde;
import io.druid.segment.serde.ComplexColumnPartSerde;
import io.druid.segment.serde.ComplexColumnPartSupplier;
import io.druid.segment.serde.ComplexMetricExtractor;
import io.druid.segment.serde.ComplexMetricSerde;

import java.nio.ByteBuffer;
import java.util.Iterator;
import java.util.List;

public class ApproximateHistogramFoldingSerde extends ComplexMetricSerde
{
  private static Ordering comparator = new Ordering()
  {
    @Override
    public int compare(
        ApproximateHistogram arg1, ApproximateHistogram arg2
    )
    {
      return ApproximateHistogramAggregator.COMPARATOR.compare(arg1, arg2);
    }
  }.nullsFirst();

  @Override
  public String getTypeName()
  {
    return "approximateHistogram";
  }

  @Override
  public ComplexMetricExtractor getExtractor()
  {
    return new ComplexMetricExtractor()
    {
      @Override
      public Class extractedClass()
      {
        return ApproximateHistogram.class;
      }

      @Override
      public ApproximateHistogram extractValue(InputRow inputRow, String metricName)
      {
        Object rawValue = inputRow.getRaw(metricName);

        if (rawValue instanceof ApproximateHistogram) {
          return (ApproximateHistogram) rawValue;
        } else {
          List dimValues = inputRow.getDimension(metricName);
          if (dimValues != null && dimValues.size() > 0) {
            Iterator values = dimValues.iterator();

            ApproximateHistogram h = new ApproximateHistogram();

            while (values.hasNext()) {
              float value = Float.parseFloat(values.next());
              h.offer(value);
            }
            return h;
          } else {
            return new ApproximateHistogram(0);
          }
        }
      }
    };
  }

  @Override
  public ColumnPartSerde deserializeColumn(
      ByteBuffer byteBuffer, ColumnBuilder columnBuilder
  )
  {
    final GenericIndexed column = GenericIndexed.read(byteBuffer, getObjectStrategy());

    columnBuilder.setComplexColumn(new ComplexColumnPartSupplier(getTypeName(), column));

    return new ComplexColumnPartSerde(column, getTypeName());
  }

  public ObjectStrategy getObjectStrategy()
  {
    return new ObjectStrategy()
    {
      @Override
      public Class getClazz()
      {
        return ApproximateHistogram.class;
      }

      @Override
      public ApproximateHistogram fromByteBuffer(ByteBuffer buffer, int numBytes)
      {
        final ByteBuffer readOnlyBuffer = buffer.asReadOnlyBuffer();
        readOnlyBuffer.limit(readOnlyBuffer.position() + numBytes);
        return ApproximateHistogram.fromBytes(readOnlyBuffer);
      }

      @Override
      public byte[] toBytes(ApproximateHistogram h)
      {
        if (h == null) {
          return new byte[]{};
        }
        return h.toBytes();
      }

      @Override
      public int compare(ApproximateHistogram o1, ApproximateHistogram o2)
      {
        return comparator.compare(o1, o2);
      }
    };
  }
}