| /** |
| * |
| * Licensed to the Apache Software Foundation (ASF) under one |
| * or more contributor license agreements. See the NOTICE file |
| * distributed with this work for additional information |
| * regarding copyright ownership. The ASF licenses this file |
| * to you under the Apache License, Version 2.0 (the |
| * "License"); you may not use this file except in compliance |
| * with the License. You may obtain a copy of the License at |
| * |
| * http://www.apache.org/licenses/LICENSE-2.0 |
| * |
| * Unless required by applicable law or agreed to in writing, software |
| * distributed under the License is distributed on an "AS IS" BASIS, |
| * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| * See the License for the specific language governing permissions and |
| * limitations under the License. |
| */ |
| package org.apache.hadoop.hbase; |
| |
| import java.util.ArrayList; |
| import java.util.Comparator; |
| import java.util.List; |
| import java.util.Map; |
| import java.util.NavigableSet; |
| import java.util.TreeMap; |
| import java.util.TreeSet; |
| |
| import org.apache.hadoop.classification.InterfaceAudience; |
| |
| |
| /** |
| * Data structure to describe the distribution of HDFS blocks amount hosts |
| */ |
| @InterfaceAudience.Private |
| public class HDFSBlocksDistribution { |
| private Map<String,HostAndWeight> hostAndWeights = null; |
| private long uniqueBlocksTotalWeight = 0; |
| |
| /** |
| * Stores the hostname and weight for that hostname. |
| * |
| * This is used when determining the physical locations of the blocks making |
| * up a region. |
| * |
| * To make a prioritized list of the hosts holding the most data of a region, |
| * this class is used to count the total weight for each host. The weight is |
| * currently just the size of the file. |
| */ |
| public static class HostAndWeight { |
| |
| private String host; |
| private long weight; |
| |
| /** |
| * Constructor |
| * @param host the host name |
| * @param weight the weight |
| */ |
| public HostAndWeight(String host, long weight) { |
| this.host = host; |
| this.weight = weight; |
| } |
| |
| /** |
| * add weight |
| * @param weight the weight |
| */ |
| public void addWeight(long weight) { |
| this.weight += weight; |
| } |
| |
| /** |
| * @return the host name |
| */ |
| public String getHost() { |
| return host; |
| } |
| |
| /** |
| * @return the weight |
| */ |
| public long getWeight() { |
| return weight; |
| } |
| |
| /** |
| * comparator used to sort hosts based on weight |
| */ |
| public static class WeightComparator implements Comparator<HostAndWeight> { |
| @Override |
| public int compare(HostAndWeight l, HostAndWeight r) { |
| if(l.getWeight() == r.getWeight()) { |
| return l.getHost().compareTo(r.getHost()); |
| } |
| return l.getWeight() < r.getWeight() ? -1 : 1; |
| } |
| } |
| } |
| |
| /** |
| * Constructor |
| */ |
| public HDFSBlocksDistribution() { |
| this.hostAndWeights = |
| new TreeMap<String,HostAndWeight>(); |
| } |
| |
| /** |
| * @see java.lang.Object#toString() |
| */ |
| @Override |
| public synchronized String toString() { |
| return "number of unique hosts in the disribution=" + |
| this.hostAndWeights.size(); |
| } |
| |
| /** |
| * add some weight to a list of hosts, update the value of unique block weight |
| * @param hosts the list of the host |
| * @param weight the weight |
| */ |
| public void addHostsAndBlockWeight(String[] hosts, long weight) { |
| if (hosts == null || hosts.length == 0) { |
| throw new NullPointerException("empty hosts"); |
| } |
| addUniqueWeight(weight); |
| for (String hostname : hosts) { |
| addHostAndBlockWeight(hostname, weight); |
| } |
| } |
| |
| /** |
| * add some weight to the total unique weight |
| * @param weight the weight |
| */ |
| private void addUniqueWeight(long weight) { |
| uniqueBlocksTotalWeight += weight; |
| } |
| |
| |
| /** |
| * add some weight to a specific host |
| * @param host the host name |
| * @param weight the weight |
| */ |
| private void addHostAndBlockWeight(String host, long weight) { |
| if (host == null) { |
| throw new NullPointerException("Passed hostname is null"); |
| } |
| |
| HostAndWeight hostAndWeight = this.hostAndWeights.get(host); |
| if(hostAndWeight == null) { |
| hostAndWeight = new HostAndWeight(host, weight); |
| this.hostAndWeights.put(host, hostAndWeight); |
| } else { |
| hostAndWeight.addWeight(weight); |
| } |
| } |
| |
| /** |
| * @return the hosts and their weights |
| */ |
| public Map<String,HostAndWeight> getHostAndWeights() { |
| return this.hostAndWeights; |
| } |
| |
| /** |
| * return the weight for a specific host, that will be the total bytes of all |
| * blocks on the host |
| * @param host the host name |
| * @return the weight of the given host |
| */ |
| public long getWeight(String host) { |
| long weight = 0; |
| if (host != null) { |
| HostAndWeight hostAndWeight = this.hostAndWeights.get(host); |
| if(hostAndWeight != null) { |
| weight = hostAndWeight.getWeight(); |
| } |
| } |
| return weight; |
| } |
| |
| /** |
| * @return the sum of all unique blocks' weight |
| */ |
| public long getUniqueBlocksTotalWeight() { |
| return uniqueBlocksTotalWeight; |
| } |
| |
| /** |
| * return the locality index of a given host |
| * @param host the host name |
| * @return the locality index of the given host |
| */ |
| public float getBlockLocalityIndex(String host) { |
| float localityIndex = 0; |
| HostAndWeight hostAndWeight = this.hostAndWeights.get(host); |
| if (hostAndWeight != null && uniqueBlocksTotalWeight != 0) { |
| localityIndex=(float)hostAndWeight.weight/(float)uniqueBlocksTotalWeight; |
| } |
| return localityIndex; |
| } |
| |
| |
| /** |
| * This will add the distribution from input to this object |
| * @param otherBlocksDistribution the other hdfs blocks distribution |
| */ |
| public void add(HDFSBlocksDistribution otherBlocksDistribution) { |
| Map<String,HostAndWeight> otherHostAndWeights = |
| otherBlocksDistribution.getHostAndWeights(); |
| for (Map.Entry<String, HostAndWeight> otherHostAndWeight: |
| otherHostAndWeights.entrySet()) { |
| addHostAndBlockWeight(otherHostAndWeight.getValue().host, |
| otherHostAndWeight.getValue().weight); |
| } |
| addUniqueWeight(otherBlocksDistribution.getUniqueBlocksTotalWeight()); |
| } |
| |
| /** |
| * return the sorted list of hosts in terms of their weights |
| */ |
| public List<String> getTopHosts() { |
| NavigableSet<HostAndWeight> orderedHosts = new TreeSet<HostAndWeight>( |
| new HostAndWeight.WeightComparator()); |
| orderedHosts.addAll(this.hostAndWeights.values()); |
| List<String> topHosts = new ArrayList<String>(orderedHosts.size()); |
| for(HostAndWeight haw : orderedHosts.descendingSet()) { |
| topHosts.add(haw.getHost()); |
| } |
| return topHosts; |
| } |
| |
| } |