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From walterddr <...@git.apache.org>
Subject [GitHub] flink pull request #5555: [FLINK-8689][table]Add runtime support of distinct...
Date Tue, 24 Apr 2018 03:48:27 GMT
Github user walterddr commented on a diff in the pull request:

    https://github.com/apache/flink/pull/5555#discussion_r183222451
  
    --- Diff: flink-libraries/flink-table/src/main/scala/org/apache/flink/table/functions/aggfunctions/DistinctAccumulator.scala
---
    @@ -0,0 +1,102 @@
    +/*
    + * 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.flink.table.functions.aggfunctions
    +
    +import java.lang.{Iterable => JIterable}
    +import java.util.{Map => JMap}
    +import org.apache.flink.table.api.dataview.MapView
    +
    +/**
    +  * The base class for accumulator wrapper when applying distinct aggregation.
    +  * @param realAcc the actual accumulator which gets invoke after distinct filter.
    +  * @param mapView the [[MapView]] element used to store the distinct filter hash map.
    +  * @tparam E the element type for the distinct filter hash map.
    +  * @tparam ACC the accumulator type for the realAcc.
    +  */
    +class DistinctAccumulator[E, ACC](var realAcc: ACC, var mapView: MapView[E, Integer])
{
    +  def this() {
    +    this(null.asInstanceOf[ACC], new MapView[E, Integer]())
    +  }
    +
    +  def this(realAcc: ACC) {
    +    this(realAcc, new MapView[E, Integer]())
    +  }
    +
    +  def getRealAcc: ACC = realAcc
    +
    +  def canEqual(a: Any): Boolean = a.isInstanceOf[DistinctAccumulator[E, ACC]]
    +
    +  override def equals(that: Any): Boolean =
    +    that match {
    +      case that: DistinctAccumulator[E, ACC] => that.canEqual(this) &&
    +        this.mapView == that.mapView
    +      case _ => false
    +    }
    +
    +  def add(element: E): Boolean = {
    +    if (element != null) {
    +      if (mapView.contains(element)) {
    +        mapView.put(element, mapView.get(element) + 1)
    +        false
    +      } else {
    +        mapView.put(element, 1)
    +        true
    +      }
    +    } else {
    +      false
    +    }
    +  }
    +
    +  def add(element: E, count: Int): Boolean = {
    +    if (element != null) {
    +      if (mapView.contains(element)) {
    --- End diff --
    
    +1 here as well, just in case I forgot


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