processing/src/main/java/org/apache/druid/query/topn/DimValHolder.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.druid.query.topn;

import org.apache.druid.segment.DimensionHandlerUtils;
import org.apache.druid.segment.column.ValueType;

import java.util.Map;

/**
 */
public class DimValHolder
{
  private final Object topNMetricVal;
  private final Comparable dimValue;
  private final Object dimValIndex;
  private final Map<String, Object> metricValues;

  public DimValHolder(
      Object topNMetricVal,
      Comparable dimValue,
      Object dimValIndex,
      Map<String, Object> metricValues
  )
  {
    this.topNMetricVal = topNMetricVal;
    this.dimValue = dimValue;
    this.dimValIndex = dimValIndex;
    this.metricValues = metricValues;
  }

  public Object getTopNMetricVal()
  {
    return topNMetricVal;
  }

  public Comparable getDimValue()
  {
    return dimValue;
  }

  public Object getDimValIndex()
  {
    return dimValIndex;
  }

  public Map<String, Object> getMetricValues()
  {
    return metricValues;
  }

  public static class Builder
  {
    private Object topNMetricVal;
    private Comparable dimValue;
    private Object dimValIndex;
    private Map<String, Object> metricValues;

    public Builder()
    {
      topNMetricVal = null;
      dimValue = null;
      dimValIndex = null;
      metricValues = null;
    }

    public Builder withTopNMetricVal(Object topNMetricVal)
    {
      this.topNMetricVal = topNMetricVal;
      return this;
    }

    /**
     * This method is called by {@link TopNResultBuilder#addEntry} to store query results.
     *
     * The method accepts a type argument because Jackson will deserialize numbers as integers instead of longs
     * if they are small enough. Similarly, type mismatch can arise when using floats when Jackson deserializes
     * numbers as doubles instead.
     *
     * This method will ensure that any added dimension value is converted to the expected
     * type.
     *
     * @param dimValue Dimension value from TopNResultBuilder
     * @param type     Type that dimValue should have, according to the output type of the
     *                 {@link org.apache.druid.query.dimension.DimensionSpec} associated with dimValue from the
     *                 calling TopNResultBuilder
     */
    public Builder withDimValue(Comparable dimValue, ValueType type)
    {
      this.dimValue = DimensionHandlerUtils.convertObjectToType(dimValue, type);
      return this;
    }

    public Builder withDimValIndex(Object dimValIndex)
    {
      this.dimValIndex = dimValIndex;
      return this;
    }

    public Builder withMetricValues(Map<String, Object> metricValues)
    {
      this.metricValues = metricValues;
      return this;
    }

    public DimValHolder build()
    {
      return new DimValHolder(topNMetricVal, dimValue, dimValIndex, metricValues);
    }
  }
}