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.favored;
019
020import java.util.ArrayList;
021import java.util.List;
022import java.util.Map;
023import java.util.concurrent.ConcurrentHashMap;
024import java.util.stream.Collectors;
025import org.apache.hadoop.hbase.ServerName;
026import org.apache.hadoop.hbase.client.RegionInfo;
027import org.apache.yetus.audience.InterfaceAudience;
028
029/**
030 * This class contains the mapping information between each region name and its favored region
031 * server list. Used by FavoredNodeLoadBalancer set of classes and from unit tests (hence the class
032 * is public) All the access to this class is thread-safe.
033 */
034@InterfaceAudience.Private
035public class FavoredNodesPlan {
036  /** The map between each region name and its favored region server list */
037  private final Map<String, List<ServerName>> favoredNodesMap;
038
039  public static enum Position {
040    PRIMARY,
041    SECONDARY,
042    TERTIARY
043  }
044
045  public FavoredNodesPlan() {
046    this.favoredNodesMap = new ConcurrentHashMap<>();
047  }
048
049  /**
050   * Add to existing Map of FavoredNodes.
051   */
052  void updateFavoredNodesMap(FavoredNodesPlan fnp) {
053    this.favoredNodesMap.putAll(fnp.favoredNodesMap);
054  }
055
056  /**
057   * Update an assignment to the plan
058   */
059  public void updateFavoredNodesMap(RegionInfo region, List<ServerName> servers) {
060    if (region == null || servers == null || servers.isEmpty()) {
061      return;
062    }
063    this.favoredNodesMap.put(region.getRegionNameAsString(), servers);
064  }
065
066  /**
067   * Remove a favored node assignment
068   * @return the list of favored region server for this region based on the plan
069   */
070  List<ServerName> removeFavoredNodes(RegionInfo region) {
071    return favoredNodesMap.remove(region.getRegionNameAsString());
072  }
073
074  /**
075   * Returns the list of favored region server for this region based on the plan
076   */
077  public List<ServerName> getFavoredNodes(RegionInfo region) {
078    return favoredNodesMap.get(region.getRegionNameAsString());
079  }
080
081  /**
082   * Return the position of the server in the favoredNodes list. Assumes the favoredNodes list is of
083   * size 3. n
084   */
085  public static Position getFavoredServerPosition(List<ServerName> favoredNodes,
086    ServerName server) {
087    if (
088      favoredNodes == null || server == null
089        || favoredNodes.size() != FavoredNodeAssignmentHelper.FAVORED_NODES_NUM
090    ) {
091      return null;
092    }
093    for (Position p : Position.values()) {
094      if (ServerName.isSameAddress(favoredNodes.get(p.ordinal()), server)) {
095        return p;
096      }
097    }
098    return null;
099  }
100
101  /**
102   * @return the mapping between each region to its favored region server list
103   */
104  public Map<String, List<ServerName>> getAssignmentMap() {
105    // Make a deep copy so changes don't harm our copy of favoredNodesMap.
106    return this.favoredNodesMap.entrySet().stream()
107      .collect(Collectors.toMap(k -> k.getKey(), v -> new ArrayList<ServerName>(v.getValue())));
108  }
109
110  public int size() {
111    return this.favoredNodesMap.size();
112  }
113
114  @Override
115  public boolean equals(Object o) {
116    if (this == o) {
117      return true;
118    }
119    if (o == null) {
120      return false;
121    }
122    if (getClass() != o.getClass()) {
123      return false;
124    }
125    // To compare the map from object o is identical to current assignment map.
126    Map<String, List<ServerName>> comparedMap = ((FavoredNodesPlan) o).favoredNodesMap;
127
128    // compare the size
129    if (comparedMap.size() != this.favoredNodesMap.size()) {
130      return false;
131    }
132
133    // compare each element in the assignment map
134    for (Map.Entry<String, List<ServerName>> entry : comparedMap.entrySet()) {
135      List<ServerName> serverList = this.favoredNodesMap.get(entry.getKey());
136      if (serverList == null && entry.getValue() != null) {
137        return false;
138      } else if (serverList != null && !serverList.equals(entry.getValue())) {
139        return false;
140      }
141    }
142    return true;
143  }
144
145  @Override
146  public int hashCode() {
147    return favoredNodesMap.hashCode();
148  }
149}