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.rel.type.RelDataType;
  
  import org.checkerframework.checker.nullness.qual.Nullable;
  
  import java.util.Map;
  
  /**
   * Factory for {@link Table} objects.
   *
   * <p>A table factory allows you to include custom tables in a model file.
   * For example, here is a model that contains a custom table that generates
   * a range of integers.
   *
   * <blockquote><pre>{
   *   version: '1.0',
   *   defaultSchema: 'MATH',
   *   schemas: [
   *     {
   *       name: 'MATH',
   *       tables: [
   *         {
   *           name: 'INTEGERS',
   *           type: 'custom',
   *           factory: 'com.acme.IntegerTable',
   *           operand: {
   *             start: 3,
   *             end: 7,
   *             column: 'N'
   *           }
   *         }
   *       ]
   *     }
   *   ]
   * }</pre></blockquote>
   *
   * <p>Given that schema, the query
   *
   * <blockquote><pre>SELECT * FROM math.integers</pre></blockquote>
   *
   * <p>returns
   *
   * <blockquote><pre>
   * +---+
   * | N |
   * +---+
   * | 3 |
   * | 4 |
   * | 5 |
   * | 6 |
   * +---+
   * </pre></blockquote>
   *
   * <p>A class that implements TableFactory specified in a schema must have a
   * public default constructor.
   *
   * @param <T> Sub-type of table created by this factory
   */
  public interface TableFactory<T extends Table> {
    /** Creates a Table.
     *
     * @param schema Schema this table belongs to
     * @param name Name of this table
     * @param operand The "operand" JSON property
     * @param rowType Row type. Specified if the "columns" JSON property.
     * @return created table
     */
    T create(
        SchemaPlus schema,
        String name,
        Map<String, Object> operand,
        @Nullable RelDataType rowType);
  }
  