pinot-core/src/main/java/org/apache/pinot/core/query/aggregation/groupby/GroupByResultHolder.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.pinot.core.query.aggregation.groupby;

/**
 * Interface for ResultHolder to store results of GroupByAggregation.
 */
public interface GroupByResultHolder {

  /**
   * Stores the given value (of type double) for the given groupKey.
   *
   * @param groupKey
   * @param value
   */
  void setValueForKey(int groupKey, double value);

  /**
   * Store the given value (of type ResultType) for the given groupKey.
   * @param groupKey
   * @param value
   */
  void setValueForKey(int groupKey, Object value);

  /**
   * Returns the result (double) for the given group by key.
   * If the group key does not exist in the result holder, returns
   * the defaultValue it was initialized with (default value of the aggregation
   * function it is holding the result for).
   *
   * @param groupKey
   * @return
   */
  double getDoubleResult(int groupKey);

  /**
   * Returns the result (ResultType) for the given group key.
   * If the group key does not exist in the result holder, returns the
   * defaultValue it was initialized with (default value of the aggregation
   * function it is holding the result for).
   *
   * @param groupKey
   * @return
   */
  <T> T getResult(int groupKey);

  /**
   * Increase internal storage if needed to store the required number
   * of unique group keys.
   *
   * @param capacity
   */
  void ensureCapacity(int capacity);
}