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 java.util.Map;
  
  /**
   * Factory for {@link Schema} objects.
   *
   * <p>A schema factory allows you to include a custom schema in a model file.
   * For example, here is a model that contains a custom schema whose tables
   * read CSV files. (See the
   * <a href="https://calcite.apache.org/javadocAggregate/org/apache/calcite/adapter/csv/package-summary.html">example CSV adapter</a>
   * for more details about this particular adapter.)
   *
   * <blockquote><pre>{
   *   "version": "1.0",
   *   "defaultSchema": "SALES",
   *   "schemas": [
   *     {
   *       "name": "SALES",
   *       "type": "custom",
   *       "factory": "org.apache.calcite.adapter.csv.CsvSchemaFactory",
   *       "mutable": true,
   *       "operand": {
   *         directory: "sales"
   *       },
   *       "tables": [
   *         {
   *           "name": "FEMALE_EMPS",
   *           "type": "view",
   *           "sql": "SELECT * FROM emps WHERE gender = 'F'"
   *          }
   *       ]
   *     }
   *   ]
   * }</pre></blockquote>
   *
   * <p>If you do not wish to allow model authors to add additional tables
   * (including views) to an instance of your schema, specify
   * 'mutable: false'.
   *
   * <p>A class that implements SchemaFactory specified in a schema must have a
   * public default constructor.
   */
  public interface SchemaFactory {
    /** Creates a Schema.
     *
     * @param parentSchema Parent schema
     * @param name Name of this schema
     * @param operand The "operand" JSON property
     * @return Created schema
     */
    Schema create(
        SchemaPlus parentSchema,
        String name,
        Map<String, Object> operand);
  }
  