/**
* 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.drill.exec.planner.sql;
import java.util.HashMap;
import org.apache.calcite.sql.SqlBasicCall;
import org.apache.calcite.sql.SqlCall;
import org.apache.calcite.sql.SqlOperator;
import org.apache.calcite.sql.fun.SqlAvgAggFunction;
import org.apache.calcite.sql.fun.SqlStdOperatorTable;
import org.apache.calcite.sql2rel.SqlRexConvertlet;
import org.apache.calcite.sql2rel.SqlRexConvertletTable;
import org.apache.calcite.sql2rel.StandardConvertletTable;
import org.apache.drill.exec.planner.sql.parser.DrillCalciteWrapperUtility;
public class DrillConvertletTable implements SqlRexConvertletTable{
public static HashMap<SqlOperator, SqlRexConvertlet> map = new HashMap<>();
public static SqlRexConvertletTable INSTANCE = new DrillConvertletTable();
static {
// Use custom convertlet for extract function
map.put(SqlStdOperatorTable.EXTRACT, DrillExtractConvertlet.INSTANCE);
map.put(SqlStdOperatorTable.AVG, new DrillAvgVarianceConvertlet(SqlAvgAggFunction.Subtype.AVG));
map.put(SqlStdOperatorTable.STDDEV_POP, new DrillAvgVarianceConvertlet(SqlAvgAggFunction.Subtype.STDDEV_POP));
map.put(SqlStdOperatorTable.STDDEV_SAMP, new DrillAvgVarianceConvertlet(SqlAvgAggFunction.Subtype.STDDEV_SAMP));
map.put(SqlStdOperatorTable.VAR_POP, new DrillAvgVarianceConvertlet(SqlAvgAggFunction.Subtype.VAR_POP));
map.put(SqlStdOperatorTable.VAR_SAMP, new DrillAvgVarianceConvertlet(SqlAvgAggFunction.Subtype.VAR_SAMP));
}
/*
* Lookup the hash table to see if we have a custom convertlet for a given
* operator, if we don't use StandardConvertletTable.
*/
@Override
public SqlRexConvertlet get(SqlCall call) {
SqlRexConvertlet convertlet;
if(call.getOperator() instanceof DrillCalciteSqlWrapper) {
final SqlOperator wrapper = call.getOperator();
final SqlOperator wrapped = DrillCalciteWrapperUtility.extractSqlOperatorFromWrapper(call.getOperator());
if ((convertlet = map.get(wrapped)) != null) {
return convertlet;
}
((SqlBasicCall) call).setOperator(wrapped);
SqlRexConvertlet sqlRexConvertlet = StandardConvertletTable.INSTANCE.get(call);
((SqlBasicCall) call).setOperator(wrapper);
return sqlRexConvertlet;
}
if ((convertlet = map.get(call.getOperator())) != null) {
return convertlet;
}
return StandardConvertletTable.INSTANCE.get(call);
}
private DrillConvertletTable() {
}
}