org.apache.calcite.adapter.druid.NaryOperatorConverter Maven / Gradle / Ivy
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/*
* 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.calcite.adapter.druid;
import org.apache.calcite.rel.type.RelDataType;
import org.apache.calcite.rex.RexCall;
import org.apache.calcite.rex.RexNode;
import org.apache.calcite.sql.SqlOperator;
import java.util.List;
import java.util.Objects;
import javax.annotation.Nullable;
/**
* Converts Calcite n-ary operators to druid expression eg (arg1 Op arg2 Op arg3)
*/
public class NaryOperatorConverter implements DruidSqlOperatorConverter {
private final SqlOperator operator;
private final String druidOperatorName;
public NaryOperatorConverter(SqlOperator operator, String druidOperatorName) {
this.operator = Objects.requireNonNull(operator);
this.druidOperatorName = Objects.requireNonNull(druidOperatorName);
}
@Override public SqlOperator calciteOperator() {
return operator;
}
@Nullable
@Override public String toDruidExpression(RexNode rexNode, RelDataType rowType,
DruidQuery druidQuery) {
final RexCall call = (RexCall) rexNode;
final List druidExpressions = DruidExpressions.toDruidExpressions(
druidQuery, rowType,
call.getOperands());
if (druidExpressions == null) {
return null;
}
return DruidExpressions.nAryOperatorCall(druidOperatorName, druidExpressions);
}
}
// End NaryOperatorConverter.java