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.ddl;
  
  import org.apache.calcite.sql.SqlCreate;
  import org.apache.calcite.sql.SqlIdentifier;
  import org.apache.calcite.sql.SqlKind;
  import org.apache.calcite.sql.SqlNode;
  import org.apache.calcite.sql.SqlNodeList;
  import org.apache.calcite.sql.SqlOperator;
  import org.apache.calcite.sql.SqlSpecialOperator;
  import org.apache.calcite.sql.SqlWriter;
  import org.apache.calcite.sql.parser.SqlParserPos;
  import org.apache.calcite.util.ImmutableNullableList;
  
  import org.checkerframework.checker.nullness.qual.Nullable;
  
  import java.util.List;
  
  import static java.util.Objects.requireNonNull;
  
  /**
   * Parse tree for {@code CREATE VIEW} statement.
   */
  public class SqlCreateView extends SqlCreate {
    public final SqlIdentifier name;
    public final @Nullable SqlNodeList columnList;
    public final SqlNode query;
  
    private static final SqlOperator OPERATOR =
        new SqlSpecialOperator("CREATE VIEW", SqlKind.CREATE_VIEW);
  
    /** Creates a SqlCreateView. */
    SqlCreateView(SqlParserPos pos, boolean replace, SqlIdentifier name,
        @Nullable SqlNodeList columnList, SqlNode query) {
      super(OPERATOR, pos, replace, false);
      this.name = requireNonNull(name, "name");
      this.columnList = columnList; // may be null
      this.query = requireNonNull(query, "query");
    }
  
    @SuppressWarnings("nullness")
    @Override public List<SqlNode> getOperandList() {
      return ImmutableNullableList.of(name, columnList, query);
    }
  
    @Override public void unparse(SqlWriter writer, int leftPrec, int rightPrec) {
      if (getReplace()) {
        writer.keyword("CREATE OR REPLACE");
      } else {
        writer.keyword("CREATE");
      }
      writer.keyword("VIEW");
      name.unparse(writer, leftPrec, rightPrec);
      if (columnList != null) {
        SqlWriter.Frame frame = writer.startList("(", ")");
        for (SqlNode c : columnList) {
          writer.sep(",");
          c.unparse(writer, 0, 0);
        }
        writer.endList(frame);
      }
      writer.keyword("AS");
      writer.newlineAndIndent();
      query.unparse(writer, 0, 0);
    }
  }
  