/*
* 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.parser.result.merger;
import lombok.Getter;
import lombok.Setter;
import lombok.ToString;
import java.util.ArrayList;
import java.util.List;
/**
* 结果归并上下文.
*
* @author zhangliang
*/
@Getter
@ToString
public final class MergeContext {
private final List<OrderByColumn> orderByColumns = new ArrayList<>();
private final List<GroupByColumn> groupByColumns = new ArrayList<>();
private final List<AggregationColumn> aggregationColumns = new ArrayList<>();
@Setter
private Limit limit;
/**
* 是否包含分组.
*
* @return 是否包含分组
*/
public boolean hasGroupBy() {
return !groupByColumns.isEmpty();
}
/**
* 判断是否为分组或者聚合计算.
* 此处将聚合计算想象成为特殊的分组计算,统一进行处理.
*
* @return true:是分组或者聚合计算 false:不是分组且不是聚合计算
*/
public boolean hasGroupByOrAggregation() {
return hasGroupBy() || !aggregationColumns.isEmpty();
}
/**
* 判断是否包含排序列.
*
* @return 是否包含排序列
*/
public boolean hasOrderBy() {
return !orderByColumns.isEmpty();
}
/**
* 判断是否有限定结果集计算.
*
* @return true:是限定结果集计算 false:不是限定结果集计算
*/
public boolean hasLimit() {
return null != limit;
}
}