/**
    *
    * 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.handler;
  
  import org.apache.commons.logging.Log;
  import org.apache.commons.logging.LogFactory;
  import org.apache.hadoop.hbase.classification.InterfaceAudience;
  import org.apache.hadoop.hbase.HRegionInfo;
  import org.apache.hadoop.hbase.Server;
  import org.apache.hadoop.hbase.executor.EventHandler;
  import org.apache.hadoop.hbase.executor.EventType;
  import org.apache.hadoop.hbase.master.AssignmentManager;
  import org.apache.hadoop.hbase.master.RegionState;
  import org.apache.hadoop.hbase.protobuf.generated.ZooKeeperProtos;
  
  /**
   * Handles CLOSED region event on Master.
   * <p>
   * If table is being disabled, deletes ZK unassigned node and removes from
   * regions in transition.
   * <p>
   * Otherwise, assigns the region to another server.
   */
  @InterfaceAudience.Private
  public class ClosedRegionHandler extends EventHandler implements TotesHRegionInfo {
    private static final Log LOG = LogFactory.getLog(ClosedRegionHandler.class);
    private final AssignmentManager assignmentManager;
    private final HRegionInfo regionInfo;
    private final ClosedPriority priority;
  
    private enum ClosedPriority {
      META (1),
      USER (2);
  
      private final int value;
      ClosedPriority(int value) {
        this.value = value;
      }
      public int getValue() {
        return value;
      }
    };
  
    public ClosedRegionHandler(Server server, AssignmentManager assignmentManager,
        HRegionInfo regionInfo) {
      super(server, EventType.RS_ZK_REGION_CLOSED);
      this.assignmentManager = assignmentManager;
      this.regionInfo = regionInfo;
      if(regionInfo.isMetaRegion()) {
        priority = ClosedPriority.META;
      } else {
        priority = ClosedPriority.USER;
      }
    }
  
    @Override
    public int getPriority() {
      return priority.getValue();
    }
  
    @Override
    public HRegionInfo getHRegionInfo() {
      return this.regionInfo;
    }
  
    @Override
    public String toString() {
      String name = "UnknownServerName";
      if(server != null && server.getServerName() != null) {
        name = server.getServerName().toString();
      }
      return getClass().getSimpleName() + "-" + name + "-" + getSeqid();
    }
  
    @Override
    public void process() {
      LOG.debug("Handling CLOSED event for " + regionInfo.getEncodedName());
      // Check if this table is being disabled or not
      if (this.assignmentManager.getTableStateManager().isTableState(this.regionInfo.getTable(),
          ZooKeeperProtos.Table.State.DISABLED, ZooKeeperProtos.Table.State.DISABLING) ||
          assignmentManager.getReplicasToClose().contains(regionInfo)) {
        assignmentManager.offlineDisabledRegion(regionInfo);
        return;
     }
     // ZK Node is in CLOSED state, assign it.
     assignmentManager.getRegionStates().setRegionStateTOCLOSED(regionInfo, null);
     // This below has to do w/ online enable/disable of a table
     assignmentManager.removeClosedRegion(regionInfo);
     assignmentManager.assign(regionInfo, true);
   }
 }