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.JsonCreator;
  import com.fasterxml.jackson.annotation.JsonProperty;
  import com.google.common.collect.ImmutableList;
  
  import org.checkerframework.checker.nullness.qual.Nullable;
  
  import java.util.ArrayList;
  import java.util.List;
  
  /**
   * Materialized view within a {@link org.apache.calcite.model.JsonLattice}.
   *
   * <p>A tile is defined in terms of its dimensionality (the grouping columns,
   * drawn from the lattice) and measures (aggregate functions applied to
   * lattice columns).
   *
   * <p>Occurs within {@link JsonLattice#tiles}.
   *
   * @see JsonRoot Description of schema elements
   */
  public class JsonTile {
    /** List of dimensions that define this tile.
     *
     * <p>Each dimension is a column from the lattice. The list of dimensions
     * defines the level of aggregation, like a {@code GROUP BY} clause.
     *
     * <p>Required, but may be empty. Each element is either a string
     * (the unique label of the column within the lattice)
     * or a string list (a pair consisting of a table alias and a column name).
     */
    public final List dimensions = new ArrayList();
  
    /** List of measures in this tile.
     *
     * <p>If not specified, uses {@link JsonLattice#defaultMeasures}.
     */
    public final List<JsonMeasure> measures;
  
    @JsonCreator
    public JsonTile(@JsonProperty("measures") @Nullable List<JsonMeasure> measures) {
      this.measures = measures == null
          ? ImmutableList.of(new JsonMeasure("count", null)) : measures;
    }
  
    public void accept(ModelHandler handler) {
      handler.visit(this);
    }
  }
  