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 Array and Array element type.
   */
  public class ArrayElementOperandTypeChecker implements SqlOperandTypeChecker {
    //~ Instance fields --------------------------------------------------------
  
    private final boolean arrayMayBeNull;
    private final boolean elementMayBeNull;
  
    //~ Constructors -----------------------------------------------------------
  
    public ArrayElementOperandTypeChecker(boolean arrayMayBeNull, boolean elementMayBeNull) {
      this.arrayMayBeNull = arrayMayBeNull;
      this.elementMayBeNull = elementMayBeNull;
    }
  
    //~ Methods ----------------------------------------------------------------
  
    @Override public boolean checkOperandTypes(
        SqlCallBinding callBinding,
        boolean throwOnFailure) {
      final SqlNode op0 = callBinding.operand(0);
      RelDataType arrayType = SqlTypeUtil.deriveType(callBinding, op0);
  
      // Check if op0 is allowed to be NULL
      if (!this.arrayMayBeNull && arrayType.getSqlTypeName() == SqlTypeName.NULL) {
        if (throwOnFailure) {
          throw callBinding.getValidator().newValidationError(op0, RESOURCE.nullIllegal());
        } else {
          return false;
        }
      }
  
      // Check that op0 is an ARRAY type
      if (!OperandTypes.ARRAY.checkSingleOperandType(
          callBinding,
          op0,
          0,
          throwOnFailure)) {
        return false;
      }
      RelDataType arrayComponentType =
          getComponentTypeOrThrow(SqlTypeUtil.deriveType(callBinding, op0));
  
      final SqlNode op1 = callBinding.operand(1);
      RelDataType elementType = SqlTypeUtil.deriveType(callBinding, op1);
  
      // Check if elementType is allowed to be NULL
      if (!this.elementMayBeNull && elementType.getSqlTypeName() == SqlTypeName.NULL) {
        if (throwOnFailure) {
          throw callBinding.getValidator().newValidationError(op1, RESOURCE.nullIllegal());
        } else {
          return false;
        }
      }
  
      RelDataType biggest =
          callBinding.getTypeFactory().leastRestrictive(
              ImmutableList.of(arrayComponentType, elementType));
      if (biggest == null) {
        if (throwOnFailure) {
          throw callBinding.newError(
              RESOURCE.typeNotComparable(
                  arrayComponentType.toString(), elementType.toString()));
        }
  
        return false;
      }
      return true;
    }
  
    @Override public SqlOperandCountRange getOperandCountRange() {
      return SqlOperandCountRanges.of(2);
    }
  
    @Override public String getAllowedSignatures(SqlOperator op, String opName) {
      return "<ARRAY> " + opName + " <ARRAY>";
    }
  }
  