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.adapter.druid;
  
  import org.apache.calcite.schema.Schema;
  import org.apache.calcite.schema.SchemaFactory;
  import org.apache.calcite.schema.SchemaPlus;
  
  import java.util.List;
  import java.util.Map;
  
  /**
   * Schema factory that creates Druid schemas.
   *
   * <table>
   *   <caption>Druid schema operands</caption>
   *   <tr>
   *     <th>Operand</th>
   *     <th>Description</th>
   *     <th>Required</th>
   *   </tr>
   *   <tr>
   *     <td>url</td>
   *     <td>URL of Druid's query node.
   *     The default is "http://localhost:8082".</td>
   *     <td>No</td>
   *   </tr>
   *   <tr>
   *     <td>coordinatorUrl</td>
   *     <td>URL of Druid's coordinator node.
   *     The default is <code>url</code>, replacing "8082" with "8081",
   *     for example "http://localhost:8081".</td>
   *     <td>No</td>
   *   </tr>
   * </table>
   */
  public class DruidSchemaFactory implements SchemaFactory {
    /** Default Druid URL. */
    public static final String DEFAULT_URL = "http://localhost:8082";
  
    @Override public Schema create(SchemaPlus parentSchema, String name,
        Map<String, Object> operand) {
      final String url = operand.get("url") instanceof String
          ? (String) operand.get("url")
          : DEFAULT_URL;
      final String coordinatorUrl = operand.get("coordinatorUrl") instanceof String
          ? (String) operand.get("coordinatorUrl")
          : url.replace(":8082", ":8081");
      // "tables" is a hidden attribute, copied in from the enclosing custom
      // schema
      final boolean containsTables =
          operand.get("tables") instanceof List
              && !((List) operand.get("tables")).isEmpty();
      return new DruidSchema(url, coordinatorUrl, !containsTables);
    }
  }
  