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.sql.type;
  
  import org.apache.calcite.rel.type.RelDataType;
  import org.apache.calcite.sql.SqlCallBinding;
  import org.apache.calcite.sql.SqlNode;
  import org.apache.calcite.sql.SqlOperandCountRange;
  import org.apache.calcite.sql.SqlOperator;
  
  import com.google.common.collect.ImmutableList;
  
  import static org.apache.calcite.sql.type.NonNullableAccessors.getComponentTypeOrThrow;
  import static org.apache.calcite.util.Static.RESOURCE;
  
  /**
   * Parameter type-checking strategy where types must be ([nullable] Multiset,
   * [nullable] Multiset), and the two types must have the same element type.
   *
   * @see MultisetSqlType#getComponentType
   */
  public class MultisetOperandTypeChecker implements SqlOperandTypeChecker {
    //~ Methods ----------------------------------------------------------------
  
    @Override public boolean checkOperandTypes(
        SqlCallBinding callBinding,
        boolean throwOnFailure) {
      final SqlNode op0 = callBinding.operand(0);
      if (!OperandTypes.MULTISET.checkSingleOperandType(
          callBinding,
          op0,
          0,
          throwOnFailure)) {
        return false;
      }
  
      final SqlNode op1 = callBinding.operand(1);
      if (!OperandTypes.MULTISET.checkSingleOperandType(
          callBinding,
          op1,
          0,
          throwOnFailure)) {
        return false;
      }
  
      // TODO: this won't work if element types are of ROW types and there is
      // a mismatch.
      RelDataType biggest =
          callBinding.getTypeFactory().leastRestrictive(
              ImmutableList.of(
                  getComponentTypeOrThrow(SqlTypeUtil.deriveType(callBinding, op0)),
                  getComponentTypeOrThrow(SqlTypeUtil.deriveType(callBinding, op1))));
      if (null == biggest) {
        if (throwOnFailure) {
          throw callBinding.newError(
              RESOURCE.typeNotComparable(
                  op0.getParserPosition().toString(),
                  op1.getParserPosition().toString()));
        }
  
        return false;
      }
      return true;
    }
  
    @Override public SqlOperandCountRange getOperandCountRange() {
      return SqlOperandCountRanges.of(2);
    }
  
    @Override public String getAllowedSignatures(SqlOperator op, String opName) {
      return "<MULTISET> " + opName + " <MULTISET>";
    }
  }
  