io.druid.sql.calcite.expression.CharacterLengthExtractionOperator Maven / Gradle / Ivy
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* Licensed to Metamarkets Group Inc. (Metamarkets) under one
* or more contributor license agreements. See the NOTICE file
* distributed with this work for additional information
* regarding copyright ownership. Metamarkets 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
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* KIND, either express or implied. See the License for the
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*/
package io.druid.sql.calcite.expression;
import io.druid.query.extraction.StrlenExtractionFn;
import io.druid.sql.calcite.planner.PlannerContext;
import org.apache.calcite.rex.RexCall;
import org.apache.calcite.rex.RexNode;
import org.apache.calcite.sql.SqlFunction;
import org.apache.calcite.sql.fun.SqlStdOperatorTable;
import java.util.List;
public class CharacterLengthExtractionOperator implements SqlExtractionOperator
{
@Override
public SqlFunction calciteFunction()
{
return SqlStdOperatorTable.CHAR_LENGTH;
}
@Override
public RowExtraction convert(
final PlannerContext plannerContext,
final List rowOrder,
final RexNode expression
)
{
final RexCall call = (RexCall) expression;
final RowExtraction arg = Expressions.toRowExtraction(
plannerContext,
rowOrder,
call.getOperands().get(0)
);
if (arg == null) {
return null;
}
return RowExtraction.of(
arg.getColumn(),
ExtractionFns.compose(StrlenExtractionFn.instance(), arg.getExtractionFn())
);
}
}