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.sql.SqlCall;
  import org.apache.calcite.sql.SqlKind;
  import org.apache.calcite.sql.SqlNode;
  import org.apache.calcite.sql.SqlWith;
  import org.apache.calcite.sql.SqlWithItem;
  import org.apache.calcite.sql.parser.SqlParserPos;
  
  import org.checkerframework.checker.nullness.qual.Nullable;
  
  /** Very similar to {@link WithItemNamespace} but created only for RECURSIVE queries. */
  class WithItemRecursiveNamespace extends WithItemNamespace {
    private final SqlWithItem withItem;
    private final SqlWithItemTableRef withItemTableRef;
  
    /**
     * Creates a Namespace for a query specified in {@code WITH RECURSIVE} clause.
     *
     * @param validator Validator
     * @param withItem A with query item specified in {@code WITH} clause
     * @param enclosingNode Enclosing node
     */
    WithItemRecursiveNamespace(SqlValidatorImpl validator,
        SqlWithItem withItem,
        @Nullable SqlNode enclosingNode) {
      super(validator, withItem, enclosingNode);
      this.withItem = withItem;
      this.withItemTableRef = new SqlWithItemTableRef(SqlParserPos.ZERO, withItem);
    }
  
    @Override protected SqlNode getQuery() {
      SqlNode call = this.withItem.query;
      while (call.getKind() == SqlKind.WITH) {
        call = ((SqlWith) call).body;
      }
      return ((SqlCall) call).operand(0);
    }
  
    @Override public @Nullable SqlNode getNode() {
      return withItemTableRef;
    }
  }
  