001/* 002 * Licensed to the Apache Software Foundation (ASF) under one 003 * or more contributor license agreements. See the NOTICE file 004 * distributed with this work for additional information 005 * regarding copyright ownership. The ASF licenses this file 006 * to you under the Apache License, Version 2.0 (the 007 * "License"); you may not use this file except in compliance 008 * with the License. You may obtain a copy of the License at 009 * 010 * http://www.apache.org/licenses/LICENSE-2.0 011 * 012 * Unless required by applicable law or agreed to in writing, software 013 * distributed under the License is distributed on an "AS IS" BASIS, 014 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 015 * See the License for the specific language governing permissions and 016 * limitations under the License. 017 */ 018package org.apache.hadoop.hbase.master.balancer; 019 020import java.util.Collection; 021import java.util.Iterator; 022import org.apache.yetus.audience.InterfaceAudience; 023 024/** 025 * Class to be used for the subset of RegionLoad costs that should be treated as rates. We do not 026 * compare about the actual rate in requests per second but rather the rate relative to the rest of 027 * the regions. 028 */ 029@InterfaceAudience.Private 030abstract class CostFromRegionLoadAsRateFunction extends CostFromRegionLoadFunction { 031 032 @Override 033 protected double getRegionLoadCost(Collection<BalancerRegionLoad> regionLoadList) { 034 Iterator<BalancerRegionLoad> iter = regionLoadList.iterator(); 035 if (!iter.hasNext()) { 036 return 0; 037 } 038 double previous = getCostFromRl(iter.next()); 039 if (!iter.hasNext()) { 040 return 0; 041 } 042 double cost = 0; 043 do { 044 double current = getCostFromRl(iter.next()); 045 cost += current >= previous ? current - previous : current; 046 previous = current; 047 } while (iter.hasNext()); 048 return Math.max(0, cost / (regionLoadList.size() - 1)); 049 } 050}