content: /*
   * The Alluxio Open Foundation licenses this work under the Apache License, version 2.0
   * (the "License"). You may not use this work except in compliance with the License, which is
   * available at www.apache.org/licenses/LICENSE-2.0
   *
   * This software is distributed on an "AS IS" basis, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND,
   * either express or implied, as more fully set forth in the License.
   *
   * See the NOTICE file distributed with this work for information regarding copyright ownership.
   */
  
  package alluxio.util;
  
  import java.util.ArrayList;
  import java.util.HashMap;
  import java.util.List;
  import java.util.Map;
  import java.util.concurrent.atomic.LongAdder;
  
  /**
   * Bucket Counter Utility.
   */
  public class BucketCounter {
    // Counts the number of values less or equal to the key
    private Map<Long, LongAdder> mCounter;
    private List<Long> mIntervals;
  
    /**
     * Bucket Counter constructor.
     *
     * @param intervals sorted intervals for bucket counting
     */
    public BucketCounter(List<Long> intervals) {
      mCounter = new HashMap<>();
      mIntervals = new ArrayList<>(intervals);
      mIntervals.add(Long.MAX_VALUE);
      for (Long interval : intervals) {
        mCounter.put(interval, new LongAdder());
      }
      mCounter.put(Long.MAX_VALUE, new LongAdder());
    }
  
    private LongAdder getStartInterval(Long value) {
      for (int i = 0; i < mIntervals.size(); i++) {
        if (mIntervals.get(i) >= value) {
          return mCounter.get(mIntervals.get(i));
        }
      }
      return mCounter.get(Long.MAX_VALUE);
    }
  
    /**
     * insert a number to be counted.
     * @param number the number to be counted
     */
    public void insert(Long number) {
      getStartInterval(number).increment();
    }
  
    /**
     * remove a number to be counted.
     * @param number the number to be counted
     */
    public void remove(Long number) {
      getStartInterval(number).decrement();
    }
  
    /**
     * @return counters
     */
    public Map<Long, Number> getCounters() {
      return new HashMap<>(mCounter);
    }
  }
  