content: /*
   * 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 org.checkerframework.checker.nullness.qual.Nullable;
  
  import java.util.List;
  
  /**
   * Binary operator conversion utility class; used to convert expressions like
   * {@code exp1 Operator exp2}.
   */
  public class BinaryOperatorConversion implements DruidSqlOperatorConverter {
    private final SqlOperator operator;
    private final String druidOperator;
  
    public BinaryOperatorConversion(final SqlOperator operator, final String druidOperator) {
      this.operator = operator;
      this.druidOperator = druidOperator;
    }
  
    @Override public SqlOperator calciteOperator() {
      return operator;
    }
  
    @Override public @Nullable String toDruidExpression(RexNode rexNode,
        RelDataType rowType, DruidQuery druidQuery) {
  
      final RexCall call = (RexCall) rexNode;
  
      final List<String> druidExpressions =
          DruidExpressions.toDruidExpressions(druidQuery, rowType,
              call.getOperands());
      if (druidExpressions == null) {
        return null;
      }
      if (druidExpressions.size() != 2) {
        throw new IllegalStateException(
            DruidQuery.format("Got binary operator[%s] with %s args?", operator.getName(),
                druidExpressions.size()));
      }
  
      return DruidQuery
          .format("(%s %s %s)", druidExpressions.get(0), druidOperator, druidExpressions.get(1));
    }
  }
  