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 {@link FavoredNodeLoadBalancer} set of classes and from unit tests (hence
032 * the class 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  /** Returns the list of favored region server for this region based on the plan */
075  public List<ServerName> getFavoredNodes(RegionInfo region) {
076    return favoredNodesMap.get(region.getRegionNameAsString());
077  }
078
079  /**
080   * Return the position of the server in the favoredNodes list. Assumes the favoredNodes list is of
081   * size 3. n
082   */
083  public static Position getFavoredServerPosition(List<ServerName> favoredNodes,
084    ServerName server) {
085    if (
086      favoredNodes == null || server == null
087        || favoredNodes.size() != FavoredNodeAssignmentHelper.FAVORED_NODES_NUM
088    ) {
089      return null;
090    }
091    for (Position p : Position.values()) {
092      if (ServerName.isSameAddress(favoredNodes.get(p.ordinal()), server)) {
093        return p;
094      }
095    }
096    return null;
097  }
098
099  /**
100   * Return the mapping between each region to its favored region server list.
101   */
102  public Map<String, List<ServerName>> getAssignmentMap() {
103    // Make a deep copy so changes don't harm our copy of favoredNodesMap.
104    return this.favoredNodesMap.entrySet().stream()
105      .collect(Collectors.toMap(k -> k.getKey(), v -> new ArrayList<ServerName>(v.getValue())));
106  }
107
108  public int size() {
109    return this.favoredNodesMap.size();
110  }
111
112  @Override
113  public boolean equals(Object o) {
114    if (this == o) {
115      return true;
116    }
117    if (o == null) {
118      return false;
119    }
120    if (!(o instanceof FavoredNodesPlan)) {
121      return false;
122    }
123    // To compare the map from object o is identical to current assignment map.
124    Map<String, List<ServerName>> comparedMap = ((FavoredNodesPlan) o).favoredNodesMap;
125
126    // compare the size
127    if (comparedMap.size() != this.favoredNodesMap.size()) {
128      return false;
129    }
130
131    // compare each element in the assignment map
132    for (Map.Entry<String, List<ServerName>> entry : comparedMap.entrySet()) {
133      List<ServerName> serverList = this.favoredNodesMap.get(entry.getKey());
134      if (serverList == null && entry.getValue() != null) {
135        return false;
136      } else if (serverList != null && !serverList.equals(entry.getValue())) {
137        return false;
138      }
139    }
140    return true;
141  }
142
143  @Override
144  public int hashCode() {
145    return favoredNodesMap.hashCode();
146  }
147}