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.validate;
  
  import org.apache.calcite.rel.type.RelDataType;
  import org.apache.calcite.schema.TableFunction;
  import org.apache.calcite.sql.SqlFunctionCategory;
  import org.apache.calcite.sql.SqlIdentifier;
  import org.apache.calcite.sql.SqlKind;
  import org.apache.calcite.sql.SqlOperatorBinding;
  import org.apache.calcite.sql.SqlSyntax;
  import org.apache.calcite.sql.SqlTableFunction;
  import org.apache.calcite.sql.type.SqlOperandMetadata;
  import org.apache.calcite.sql.type.SqlOperandTypeChecker;
  import org.apache.calcite.sql.type.SqlOperandTypeInference;
  import org.apache.calcite.sql.type.SqlReturnTypeInference;
  import org.apache.calcite.util.Util;
  
  import org.checkerframework.checker.nullness.qual.Nullable;
  
  import java.lang.reflect.Type;
  import java.util.List;
  
  /**
   * User-defined table function.
   *
   * <p>Created by the validator, after resolving a function call to a function
   * defined in a Calcite schema.
  */
  public class SqlUserDefinedTableFunction extends SqlUserDefinedFunction
      implements SqlTableFunction {
    @Deprecated // to be removed before 2.0
    public SqlUserDefinedTableFunction(SqlIdentifier opName,
        SqlReturnTypeInference returnTypeInference,
        SqlOperandTypeInference operandTypeInference,
        @Nullable SqlOperandTypeChecker operandTypeChecker,
        List<RelDataType> paramTypes, // no longer used
        TableFunction function) {
      this(opName, SqlKind.OTHER_FUNCTION, returnTypeInference,
          operandTypeInference,
          operandTypeChecker instanceof SqlOperandMetadata
              ? (SqlOperandMetadata) operandTypeChecker : null, function);
      Util.discard(paramTypes);
    }
  
    /** Creates a user-defined table function. */
    public SqlUserDefinedTableFunction(SqlIdentifier opName, SqlKind kind,
        SqlReturnTypeInference returnTypeInference,
        SqlOperandTypeInference operandTypeInference,
        @Nullable SqlOperandMetadata operandMetadata,
        TableFunction function) {
      super(opName, kind, returnTypeInference, operandTypeInference,
          operandMetadata, function,
          SqlFunctionCategory.USER_DEFINED_TABLE_FUNCTION, SqlSyntax.FUNCTION);
    }
  
    /**
     * Returns function that implements given operator call.
     *
     * @return function that implements given operator call
     */
    @Override public TableFunction getFunction() {
      return (TableFunction) super.getFunction();
    }
  
    @Override public SqlReturnTypeInference getRowTypeInference() {
      return this::inferRowType;
    }
  
    private RelDataType inferRowType(SqlOperatorBinding callBinding) {
      List<@Nullable Object> arguments =
          SqlUserDefinedTableMacro.convertArguments(callBinding, function,
              getNameAsId(), false);
      return getFunction().getRowType(callBinding.getTypeFactory(), arguments);
    }
  
    /**
     * Returns the row type of the table yielded by this function when
     * applied to given arguments. Only literal arguments are passed,
     * non-literal are replaced with default values (null, 0, false, etc).
     *
     * @param callBinding Operand bound to arguments
     * @return element type of the table (e.g. {@code Object[].class})
     */
    public Type getElementType(SqlOperatorBinding callBinding) {
      List<@Nullable Object> arguments =
          SqlUserDefinedTableMacro.convertArguments(callBinding, function,
              getNameAsId(), false);
      return getFunction().getElementType(arguments);
    }
  }
  