/**
* 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.hadoop.hive.ql.udf.generic;
import org.apache.hadoop.hive.ql.exec.Description;
import org.apache.hadoop.hive.ql.exec.WindowFunctionDescription;
@WindowFunctionDescription(
description = @Description(
name = "dense_rank",
value = "_FUNC_(x) The difference between RANK and DENSE_RANK is that DENSE_RANK leaves no " +
"gaps in ranking sequence when there are ties. That is, if you were " +
"ranking a competition using DENSE_RANK and had three people tie for " +
"second place, you would say that all three were in second place and " +
"that the next person came in third."
),
supportsWindow = false,
pivotResult = true,
rankingFunction = true,
impliesOrder = true
)
public class GenericUDAFDenseRank extends GenericUDAFRank {
@Override
protected GenericUDAFAbstractRankEvaluator createEvaluator() {
return new GenericUDAFDenseRankEvaluator();
}
public static class GenericUDAFDenseRankEvaluator extends GenericUDAFRankEvaluator {
/*
* Called when the value in the partition has changed. Update the currentRank
*/
@Override
protected void nextRank(RankBuffer rb) {
rb.currentRank++;
}
}
}