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
  17 /**
  18  * This limiter will refill resources at every TimeUnit/resources interval. For example: For a
  19  * limiter configured with 10resources/second, then 1 resource will be refilled after every 100ms
  20  * (1sec/10resources)
  21  */
  22 @InterfaceAudience.Private
  23 @InterfaceStability.Evolving
  24 public class AverageIntervalRateLimiter extends RateLimiter {
  25   private long nextRefillTime = -1L;
  26
  27   @Override
  28   public long refill(long limit) {
  29     final long now = EnvironmentEdgeManager.currentTime();
  30     if (nextRefillTime == -1) {
  31       // Till now no resource has been consumed.
  32       nextRefillTime = EnvironmentEdgeManager.currentTime();
  33       return limit;
  34     }
  35
  36     long timeInterval = now - nextRefillTime;
  37     long delta = 0;
  38     long timeUnitInMillis = super.getTimeUnitInMillis();
  39     if (timeInterval >= timeUnitInMillis) {
  40       delta = limit;
  41     } else if (timeInterval > 0) {
  42       double r = ((double)timeInterval / (double)timeUnitInMillis) * limit;
  43       delta = (long)r;
  44     }
  45
  46     if (delta > 0) {
  47       this.nextRefillTime = now;
  48     }
  49
  50     return delta;
  51   }
  52
  53   @Override
  54   public long getWaitInterval(long limit, long available, long amount) {
  55     if (nextRefillTime == -1) {
  56       return 0;
  57     }
  58
  59     double r = ((double)(amount - available)) * super.getTimeUnitInMillis() / limit;
  60     return (long)r;
  61   }
  62
  63   // This method is for strictly testing purpose only
  64   @Override
  65   public void setNextRefillTime(long nextRefillTime) {
  66     this.nextRefillTime = nextRefillTime;
  67   }
  68
  69   @Override
  70   public long getNextRefillTime() {
  71     return this.nextRefillTime;
  72   }
  73
  74 }