001/**
002 * Licensed to the Apache Software Foundation (ASF) under one or more contributor license
003 * agreements. See the NOTICE file distributed with this work for additional information regarding
004 * copyright ownership. The ASF licenses this file to you under the Apache License, Version 2.0 (the
005 * "License"); you may not use this file except in compliance with the License. You may obtain a
006 * copy of the License at http://www.apache.org/licenses/LICENSE-2.0 Unless required by applicable
007 * law or agreed to in writing, software distributed under the License is distributed on an "AS IS"
008 * BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the License
009 * for the specific language governing permissions and limitations under the License.
010 */
011package org.apache.hadoop.hbase.quotas;
012
013import org.apache.yetus.audience.InterfaceAudience;
014import org.apache.yetus.audience.InterfaceStability;
015import org.apache.hadoop.hbase.util.EnvironmentEdgeManager;
016
017/**
018 * This limiter will refill resources at every TimeUnit/resources interval. For example: For a
019 * limiter configured with 10resources/second, then 1 resource will be refilled after every 100ms
020 * (1sec/10resources)
021 */
022@InterfaceAudience.Private
023@InterfaceStability.Evolving
024public class AverageIntervalRateLimiter extends RateLimiter {
025  private long nextRefillTime = -1L;
026
027  @Override
028  public long refill(long limit) {
029    final long now = EnvironmentEdgeManager.currentTime();
030    if (nextRefillTime == -1) {
031      // Till now no resource has been consumed.
032      nextRefillTime = EnvironmentEdgeManager.currentTime();
033      return limit;
034    }
035
036    long timeInterval = now - nextRefillTime;
037    long delta = 0;
038    long timeUnitInMillis = super.getTimeUnitInMillis();
039    if (timeInterval >= timeUnitInMillis) {
040      delta = limit;
041    } else if (timeInterval > 0) {
042      double r = ((double)timeInterval / (double)timeUnitInMillis) * limit;
043      delta = (long)r;
044    }
045
046    if (delta > 0) {
047      this.nextRefillTime = now;
048    }
049
050    return delta;
051  }
052
053  @Override
054  public long getWaitInterval(long limit, long available, long amount) {
055    if (nextRefillTime == -1) {
056      return 0;
057    }
058
059    double r = ((double)(amount - available)) * super.getTimeUnitInMillis() / limit;
060    return (long)r;
061  }
062
063  // This method is for strictly testing purpose only
064  @Override
065  public void setNextRefillTime(long nextRefillTime) {
066    this.nextRefillTime = nextRefillTime;
067  }
068
069  @Override
070  public long getNextRefillTime() {
071    return this.nextRefillTime;
072  }
073
074}