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;
  
  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;
  
  /**
   * A <code>SqlDescribeTable</code> is a node of a parse tree that represents a
   * {@code DESCRIBE TABLE} statement.
   */
  public class SqlDescribeTable extends SqlCall {
  
    public static final SqlSpecialOperator OPERATOR =
        new SqlSpecialOperator("DESCRIBE_TABLE", SqlKind.DESCRIBE_TABLE) {
          @SuppressWarnings("argument.type.incompatible")
          @Override public SqlCall createCall(@Nullable SqlLiteral functionQualifier,
              SqlParserPos pos, @Nullable SqlNode... operands) {
            return new SqlDescribeTable(pos, (SqlIdentifier) operands[0],
                (@Nullable SqlIdentifier) operands[1]);
          }
        };
  
    SqlIdentifier table;
    @Nullable SqlIdentifier column;
  
    /** Creates a SqlDescribeTable. */
    public SqlDescribeTable(SqlParserPos pos,
        SqlIdentifier table,
        @Nullable SqlIdentifier column) {
      super(pos);
      this.table = requireNonNull(table, "table");
      this.column = column;
    }
  
    @Override public void unparse(SqlWriter writer, int leftPrec, int rightPrec) {
      writer.keyword("DESCRIBE");
      writer.keyword("TABLE");
      table.unparse(writer, leftPrec, rightPrec);
      if (column != null) {
        column.unparse(writer, leftPrec, rightPrec);
      }
    }
  
    @SuppressWarnings("assignment.type.incompatible")
    @Override public void setOperand(int i, @Nullable SqlNode operand) {
      switch (i) {
      case 0:
        table = (SqlIdentifier) operand;
        break;
      case 1:
        column = (SqlIdentifier) operand;
        break;
      default:
        throw new AssertionError(i);
      }
    }
  
    @Override public SqlOperator getOperator() {
      return OPERATOR;
    }
  
    @SuppressWarnings("nullness")
    @Override public List<SqlNode> getOperandList() {
      return ImmutableNullableList.of(table, column);
    }
  
    public SqlIdentifier getTable() {
      return table;
    }
  
    public @Nullable SqlIdentifier getColumn() {
      return column;
    }
  }
  