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.rel.type.RelDataTypeFactory;
  import org.apache.calcite.rel.type.RelDataTypeField;
  import org.apache.calcite.sql.SqlIdentifier;
  import org.apache.calcite.sql.SqlNode;
  import org.apache.calcite.sql.SqlNodeList;
  import org.apache.calcite.sql.SqlWithItem;
  import org.apache.calcite.util.Pair;
  
  import org.checkerframework.checker.nullness.qual.Nullable;
  
  /** Very similar to {@link AliasNamespace}. */
  class WithItemNamespace extends AbstractNamespace {
    private final SqlWithItem withItem;
  
    WithItemNamespace(SqlValidatorImpl validator, SqlWithItem withItem,
        @Nullable SqlNode enclosingNode) {
      super(validator, enclosingNode);
      this.withItem = withItem;
    }
  
    @Override protected RelDataType validateImpl(RelDataType targetRowType) {
      final SqlValidatorNamespace childNs =
          validator.getNamespaceOrThrow(getQuery());
      final RelDataType rowType = childNs.getRowTypeSansSystemColumns();
      filterRequirement = childNs.getFilterRequirement();
      SqlNodeList columnList = withItem.columnList;
      if (columnList == null) {
        return rowType;
      }
      final RelDataTypeFactory.Builder builder =
          validator.getTypeFactory().builder();
      Pair.forEach(SqlIdentifier.simpleNames(columnList),
          rowType.getFieldList(),
          (name, field) -> builder.add(name, field.getType()));
      return builder.build();
    }
  
    /** Returns the node from which {@link #validateImpl(RelDataType)} determines
     * the namespace. */
    protected SqlNode getQuery() {
      return withItem.query;
    }
  
    @Override public @Nullable SqlNode getNode() {
      return withItem;
    }
  
    @Override public String translate(String name) {
      if (withItem.columnList == null) {
        return name;
      }
      final RelDataType underlyingRowType =
            validator.getValidatedNodeType(withItem.query);
      int i = 0;
      for (RelDataTypeField field : getRowType().getFieldList()) {
        if (field.getName().equals(name)) {
          return underlyingRowType.getFieldList().get(i).getName();
        }
        ++i;
      }
      throw new AssertionError("unknown field '" + name
          + "' in rowtype " + underlyingRowType);
    }
  }
  