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 com.alibaba.metrics;
  
  import java.util.Map;
  
  /**
   * 提供分桶计数功能，每个桶统计一定时间间隔内的计数。
   * BucketCounter只保留最近N个时间间隔内的计数，再老的会被丢弃。
   * 同时保存从创建开始到现在的累计计数。
   */
  public interface BucketCounter extends Counter {
  
      /**
       * update the counter to the given bucket
       */
      void update();
  
      /**
       * update the counter to the given bucket
       */
      void update(long n);
  
      /**
       * Return the bucket count, keyed by timestamp
       * @return the bucket count, keyed by timestamp
       */
      Map<Long, Long> getBucketCounts();
  
      /**
       * Return the bucket count, keyed by timestamp, since (including) the startTime.
       * 返回从startTime开始的分桶统计功能
       * @param startTime 查询起始时间, 单位是毫秒
       * @return the bucket count, keyed by timestamp
       */
      Map<Long, Long> getBucketCounts(long startTime);
  
      /**
       * Get the interval of the bucket
       * @return the interval of the bucket
       */
      int getBucketInterval();
  }
  