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.schema;
  
  import org.apache.calcite.plan.RelOptTable;
  import org.apache.calcite.rel.RelNode;
  
  /**
   * Extension to {@link Table} that specifies how it is to be translated to
   * a {@link org.apache.calcite.rel.RelNode relational expression}.
   *
   * <p>It is optional for a Table to implement this interface. If Table does
   * not implement this interface, it will be converted to an
   * {@link org.apache.calcite.adapter.enumerable.EnumerableTableScan}.
   * Generally a Table will implement this interface to
   * create a particular subclass of RelNode, and also register rules that act
   * on that particular subclass of RelNode.
   */
  public interface TranslatableTable extends Table {
    /** Converts this table into a {@link RelNode relational expression}. */
    RelNode toRel(
        RelOptTable.ToRelContext context,
        RelOptTable relOptTable);
  }
  