hbase-server/src/main/java/org/apache/hadoop/hbase/quotas/AverageIntervalRateLimiter.java

   1 /**
   2  * Licensed to the Apache Software Foundation (ASF) under one or more contributor license
   3  * agreements. See the NOTICE file distributed with this work for additional information regarding
   4  * copyright ownership. The ASF licenses this file to you under the Apache License, Version 2.0 (the
   5  * "License"); you may not use this file except in compliance with the License. You may obtain a
   6  * copy of the License at http://www.apache.org/licenses/LICENSE-2.0 Unless required by applicable
   7  * law or agreed to in writing, software distributed under the License is distributed on an "AS IS"
   8  * BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the License
   9  * for the specific language governing permissions and limitations under the License.
  10  */
  11 package org.apache.hadoop.hbase.quotas;
  12
  13 import org.apache.yetus.audience.InterfaceAudience;
  14 import org.apache.yetus.audience.InterfaceStability;
  15 import org.apache.hadoop.hbase.util.EnvironmentEdgeManager;
  16 import org.apache.hbase.thirdparty.com.google.common.annotations.VisibleForTesting;
  17
  18 /**
  19  * This limiter will refill resources at every TimeUnit/resources interval. For example: For a
  20  * limiter configured with 10resources/second, then 1 resource will be refilled after every 100ms
  21  * (1sec/10resources)
  22  */
  23 @InterfaceAudience.Private
  24 @InterfaceStability.Evolving
  25 public class AverageIntervalRateLimiter extends RateLimiter {
  26   private long nextRefillTime = -1L;
  27
  28   @Override
  29   public long refill(long limit) {
  30     final long now = EnvironmentEdgeManager.currentTime();
  31     if (nextRefillTime == -1) {
  32       // Till now no resource has been consumed.
  33       nextRefillTime = EnvironmentEdgeManager.currentTime();
  34       return limit;
  35     }
  36
  37     long timeInterval = now - nextRefillTime;
  38     long delta = 0;
  39     long timeUnitInMillis = super.getTimeUnitInMillis();
  40     if (timeInterval >= timeUnitInMillis) {
  41       delta = limit;
  42     } else if (timeInterval > 0) {
  43       double r = ((double)timeInterval / (double)timeUnitInMillis) * limit;
  44       delta = (long)r;
  45     }
  46
  47     if (delta > 0) {
  48       this.nextRefillTime = now;
  49     }
  50
  51     return delta;
  52   }
  53
  54   @Override
  55   public long getWaitInterval(long limit, long available, long amount) {
  56     if (nextRefillTime == -1) {
  57       return 0;
  58     }
  59
  60     double r = ((double)(amount - available)) * super.getTimeUnitInMillis() / limit;
  61     return (long)r;
  62   }
  63
  64   // This method is for strictly testing purpose only
  65   @VisibleForTesting
  66   @Override
  67   public void setNextRefillTime(long nextRefillTime) {
  68     this.nextRefillTime = nextRefillTime;
  69   }
  70
  71   @VisibleForTesting
  72   @Override
  73   public long getNextRefillTime() {
  74     return this.nextRefillTime;
  75   }
  76
  77 }