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 java.util.Locale;
  
  /**
   * A strategy by which Druid rolls up rows into sub-totals based on their
   * timestamp values.
   *
   * <p>Typical granularities are based upon time units (e.g. 1 day or
   * 15 minutes). A special granularity, all, combines all rows into a single
   * total.
   *
   * <p>A Granularity instance is immutable, and generates a JSON string as
   * part of a Druid query.
   *
   * @see Granularities
   */
  public interface Granularity extends DruidJson {
    /** Type of supported periods for granularity. */
    enum Type {
      ALL,
      YEAR,
      QUARTER,
      MONTH,
      WEEK,
      DAY,
      HOUR,
      MINUTE,
      SECOND;
  
      /** Lower-case name, e.g. "all", "minute". */
      public final String lowerName = name().toLowerCase(Locale.ROOT);
    }
  
    Type getType();
  }
  