/*
 * 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.phoenix.expression.aggregator;

import org.apache.hadoop.hbase.io.ImmutableBytesWritable;
import org.apache.phoenix.expression.Expression;
import org.apache.phoenix.schema.tuple.Tuple;

/**
 * Interface to abstract the incremental calculation of an aggregated value.
 * @since 0.1
 */
public interface Aggregator extends Expression {

  /**
   * Incrementally aggregate the value with the current row
   * @param tuple the result containing all the key values of the row
   * @param ptr   the bytes pointer to the underlying result
   */
  public void aggregate(Tuple tuple, ImmutableBytesWritable ptr);

  /**
   * Get the size in bytes
   */
  public int getSize();

  /**
   * Determines whether or not we should track the heap size as this aggregator is executing on the
   * server side.
   * @return true if the size should be tracked and false otherwise.
   */
  public boolean trackSize();
}
