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.model;
  
  import com.fasterxml.jackson.annotation.JsonSubTypes;
  import com.fasterxml.jackson.annotation.JsonTypeInfo;
  
  import org.checkerframework.checker.nullness.qual.Nullable;
  
  import java.util.ArrayList;
  import java.util.List;
  
  import static java.util.Objects.requireNonNull;
  
  /**
   * Table schema element.
   *
   * <p>Occurs within {@link JsonMapSchema#tables}.
   *
   * @see JsonRoot Description of schema elements
   */
  @JsonTypeInfo(
      use = JsonTypeInfo.Id.NAME,
      property = "type",
      defaultImpl = JsonCustomTable.class)
  @JsonSubTypes({
      @JsonSubTypes.Type(value = JsonCustomTable.class, name = "custom"),
      @JsonSubTypes.Type(value = JsonView.class, name = "view") })
  public abstract class JsonTable {
    /** Name of this table.
     *
     * <p>Required. Must be unique within the schema.
     */
    public final String name;
  
    /** Definition of the columns of this table.
     *
     * <p>Required for some kinds of type,
     * optional for others (such as {@link JsonView}).
     */
    public final List<JsonColumn> columns = new ArrayList<>();
  
    /** Information about whether the table can be streamed, and if so, whether
     * the history of the table is also available. */
    public final @Nullable JsonStream stream;
  
    protected JsonTable(String name, @Nullable JsonStream stream) {
      this.name = requireNonNull(name, "name");
      this.stream = stream;
    }
  
    public abstract void accept(ModelHandler handler);
  }
  