org.apache.hadoop.hbase.master.balancer.FavoredNodesPlan.java Source code

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Here is the source code for org.apache.hadoop.hbase.master.balancer.FavoredNodesPlan.java

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/**
 *
 * 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.master.balancer;

import java.util.List;
import java.util.Map;
import java.util.concurrent.ConcurrentHashMap;

import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.apache.hadoop.classification.InterfaceAudience;
import org.apache.hadoop.hbase.HRegionInfo;
import org.apache.hadoop.hbase.ServerName;

/**
 * This class contains the mapping information between each region and
 * its favored region server list. Used by {@link FavoredNodeLoadBalancer} set
 * of classes and from unit tests (hence the class is public)
 *
 * All the access to this class is thread-safe.
 */
@InterfaceAudience.Private
public class FavoredNodesPlan {
    protected static final Log LOG = LogFactory.getLog(FavoredNodesPlan.class.getName());

    /** the map between each region and its favored region server list */
    private Map<HRegionInfo, List<ServerName>> favoredNodesMap;

    public static enum Position {
        PRIMARY, SECONDARY, TERTIARY;
    };

    public FavoredNodesPlan() {
        favoredNodesMap = new ConcurrentHashMap<HRegionInfo, List<ServerName>>();
    }

    /**
     * Add an assignment to the plan
     * @param region
     * @param servers
     */
    public synchronized void updateFavoredNodesMap(HRegionInfo region, List<ServerName> servers) {
        if (region == null || servers == null || servers.size() == 0)
            return;
        this.favoredNodesMap.put(region, servers);
    }

    /**
     * @param region
     * @return the list of favored region server for this region based on the plan
     */
    public synchronized List<ServerName> getFavoredNodes(HRegionInfo region) {
        return favoredNodesMap.get(region);
    }

    /**
     * Return the position of the server in the favoredNodes list. Assumes the
     * favoredNodes list is of size 3.
     * @param favoredNodes
     * @param server
     * @return position
     */
    public static Position getFavoredServerPosition(List<ServerName> favoredNodes, ServerName server) {
        if (favoredNodes == null || server == null
                || favoredNodes.size() != FavoredNodeAssignmentHelper.FAVORED_NODES_NUM) {
            return null;
        }
        for (Position p : Position.values()) {
            if (ServerName.isSameHostnameAndPort(favoredNodes.get(p.ordinal()), server)) {
                return p;
            }
        }
        return null;
    }

    /**
     * @return the mapping between each region to its favored region server list
     */
    public synchronized Map<HRegionInfo, List<ServerName>> getAssignmentMap() {
        return this.favoredNodesMap;
    }

    /**
     * Add an assignment to the plan
     * @param region
     * @param servers
     */
    public synchronized void updateAssignmentPlan(HRegionInfo region, List<ServerName> servers) {
        if (region == null || servers == null || servers.size() == 0)
            return;
        this.favoredNodesMap.put(region, servers);
        LOG.info("Update the assignment plan for region " + region.getRegionNameAsString() + " ; favored nodes "
                + FavoredNodeAssignmentHelper.getFavoredNodesAsString(servers));
    }

    @Override
    public boolean equals(Object o) {
        if (this == o) {
            return true;
        }
        if (o == null) {
            return false;
        }
        if (getClass() != o.getClass()) {
            return false;
        }
        // To compare the map from objec o is identical to current assignment map.
        Map<HRegionInfo, List<ServerName>> comparedMap = ((FavoredNodesPlan) o).getAssignmentMap();

        // compare the size
        if (comparedMap.size() != this.favoredNodesMap.size())
            return false;

        // compare each element in the assignment map
        for (Map.Entry<HRegionInfo, List<ServerName>> entry : comparedMap.entrySet()) {
            List<ServerName> serverList = this.favoredNodesMap.get(entry.getKey());
            if (serverList == null && entry.getValue() != null) {
                return false;
            } else if (serverList != null && !serverList.equals(entry.getValue())) {
                return false;
            }
        }
        return true;
    }

    @Override
    public int hashCode() {
        return favoredNodesMap.hashCode();
    }
}