/*
* Copyright 1999-2015 dangdang.com.
* <p>
* Licensed 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.
* </p>
*/
package com.dangdang.ddframe.rdb.sharding.merger.pipeline.coupling.aggregation;
import com.dangdang.ddframe.rdb.sharding.parser.result.merger.AggregationColumn.AggregationType;
import lombok.AccessLevel;
import lombok.RequiredArgsConstructor;
/**
* 聚合函数结果集归并单元工厂.
*
* @author gaohongtao
*/
@RequiredArgsConstructor(access = AccessLevel.PRIVATE)
public final class AggregationUnitFactory {
public static AggregationUnit create(final AggregationType type) {
switch (type) {
case MAX:
return new ComparableAggregationUnit(false);
case MIN:
return new ComparableAggregationUnit(true);
case SUM:
case COUNT:
return new AccumulationAggregationUnit();
case AVG:
return new AverageAggregationUnit();
default:
throw new UnsupportedOperationException(type.name());
}
}
}