com.arcadedb.query.sql.parser.AggregateProjectionSplit Maven / Gradle / Ivy
/*
* Copyright © 2021-present Arcade Data Ltd ([email protected])
*
* 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.
*
* SPDX-FileCopyrightText: 2021-present Arcade Data Ltd ([email protected])
* SPDX-License-Identifier: Apache-2.0
*/
package com.arcadedb.query.sql.parser;
import java.util.*;
/**
* This class is used by the query planner to split projections in three parts:
*
* - pre-aggregate projections
* - aggregate projections
* - post-aggregate projections
*
*
* An example:
* {@literal
* select max(a + b) + (max(b + c * 2) + 1 + 2) * 3 as foo, max(d) + max(e), f from " + className
* }
* will become
* {@literal
*
* a + b AS _$$$OALIAS$$_1, b + c * 2 AS _$$$OALIAS$$_3, d AS _$$$OALIAS$$_5, e AS _$$$OALIAS$$_7, f
*
* max(_$$$OALIAS$$_1) AS _$$$OALIAS$$_0, max(_$$$OALIAS$$_3) AS _$$$OALIAS$$_2, max(_$$$OALIAS$$_5) AS _$$$OALIAS$$_4, max(_$$$OALIAS$$_7) AS _$$$OALIAS$$_6, f
*
* _$$$OALIAS$$_0 + (_$$$OALIAS$$_2 + 1 + 2) * 3 AS `foo`, _$$$OALIAS$$_4 + _$$$OALIAS$$_6 AS `max(d) + max(e)`, f
* }
*
* @author Luigi Dell'Aquila (luigi.dellaquila-(at)-gmail.com)
*/
public class AggregateProjectionSplit {
protected static final String GENERATED_ALIAS_PREFIX = "_$$$OALIAS$$$_";
protected int nextAliasId = 0;
protected List preAggregate = new ArrayList<>();
protected List aggregate = new ArrayList<>();
public Identifier getNextAlias() {
final Identifier result = new Identifier(GENERATED_ALIAS_PREFIX + (nextAliasId++));
result.internalAlias = true;
return result;
}
public List getPreAggregate() {
return preAggregate;
}
public void setPreAggregate(final List preAggregate) {
this.preAggregate = preAggregate;
}
public List getAggregate() {
return aggregate;
}
public void setAggregate(final List aggregate) {
this.aggregate = aggregate;
}
/**
* clean the content, but NOT the counter!
*/
public void reset() {
this.preAggregate.clear();
this.aggregate.clear();
}
}