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;
016import org.apache.hbase.thirdparty.com.google.common.annotations.VisibleForTesting;
017
018/**
019 * This limiter will refill resources at every TimeUnit/resources interval. For example: For a
020 * limiter configured with 10resources/second, then 1 resource will be refilled after every 100ms
021 * (1sec/10resources)
022 */
023@InterfaceAudience.Private
024@InterfaceStability.Evolving
025public class AverageIntervalRateLimiter extends RateLimiter {
026  private long nextRefillTime = -1L;
027
028  @Override
029  public long refill(long limit) {
030    final long now = EnvironmentEdgeManager.currentTime();
031    if (nextRefillTime == -1) {
032      // Till now no resource has been consumed.
033      nextRefillTime = EnvironmentEdgeManager.currentTime();
034      return limit;
035    }
036
037    long timeInterval = now - nextRefillTime;
038    long delta = 0;
039    long timeUnitInMillis = super.getTimeUnitInMillis();
040    if (timeInterval >= timeUnitInMillis) {
041      delta = limit;
042    } else if (timeInterval > 0) {
043      double r = ((double)timeInterval / (double)timeUnitInMillis) * limit;
044      delta = (long)r;
045    }
046
047    if (delta > 0) {
048      this.nextRefillTime = now;
049    }
050
051    return delta;
052  }
053
054  @Override
055  public long getWaitInterval(long limit, long available, long amount) {
056    if (nextRefillTime == -1) {
057      return 0;
058    }
059
060    double r = ((double)(amount - available)) * super.getTimeUnitInMillis() / limit;
061    return (long)r;
062  }
063
064  // This method is for strictly testing purpose only
065  @VisibleForTesting
066  @Override
067  public void setNextRefillTime(long nextRefillTime) {
068    this.nextRefillTime = nextRefillTime;
069  }
070
071  @VisibleForTesting
072  @Override
073  public long getNextRefillTime() {
074    return this.nextRefillTime;
075  }
076
077}