/**
    *
    * 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;
  
  import java.io.IOException;
  import java.util.HashMap;
  import java.util.List;
  import java.util.Map;
  import java.util.concurrent.ExecutorService;
  
  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.ServerName;
  
  /**
   * Performs bulk reopen of the list of regions provided to it.
   */
  @InterfaceAudience.Private
  public class BulkReOpen extends BulkAssigner {
    private final Map<ServerName, List<HRegionInfo>> rsToRegions;
    private final AssignmentManager assignmentManager;
    private static final Log LOG = LogFactory.getLog(BulkReOpen.class);
  
    public BulkReOpen(final Server server,
        final Map<ServerName, List<HRegionInfo>> serverToRegions,
      final AssignmentManager am) {
      super(server);
      this.assignmentManager = am;
      this.rsToRegions = serverToRegions;
    }
  
    /**
     * Unassign all regions, so that they go through the regular region
     * assignment flow (in assignment manager) and are re-opened.
     */
    @Override
    protected void populatePool(ExecutorService pool) {
      LOG.debug("Creating threads for each region server ");
      for (Map.Entry<ServerName, List<HRegionInfo>> e : rsToRegions
          .entrySet()) {
        final List<HRegionInfo> hris = e.getValue();
        // add plans for the regions that need to be reopened
        Map<String, RegionPlan> plans = new HashMap<String, RegionPlan>();
        for (HRegionInfo hri : hris) {
          RegionPlan reOpenPlan = assignmentManager.getRegionReopenPlan(hri);
          plans.put(hri.getEncodedName(), reOpenPlan);
        }
        assignmentManager.addPlans(plans);
        pool.execute(new Runnable() {
          public void run() {
            try {
              unassign(hris);
            } catch (Throwable t) {
              LOG.warn("Failed bulking re-open " + hris.size()
                + " region(s)", t);
            }
          }
        });
      }
    }
  
   /**
    * Reopen the regions asynchronously, so always returns true immediately.
    * @return true
    */
    @Override
    protected boolean waitUntilDone(long timeout) {
      return true;
    }
  
    /**
     * Configuration knobs "hbase.bulk.reopen.threadpool.size" number of regions
     * that can be reopened concurrently. The maximum number of threads the master
     * creates is never more than the number of region servers.
     * If configuration is not defined it defaults to 20
     */
    protected int getThreadCount() {
      int defaultThreadCount = super.getThreadCount();
      return this.server.getConfiguration().getInt(
          "hbase.bulk.reopen.threadpool.size", defaultThreadCount);
   }
 
   public boolean bulkReOpen() throws InterruptedException, IOException {
     return bulkAssign();
   }
 
   /**
    * Unassign the list of regions. Configuration knobs:
    * hbase.bulk.waitbetween.reopen indicates the number of milliseconds to
    * wait before unassigning another region from this region server
    *
    * @param regions
    * @throws InterruptedException
    */
   private void unassign(
       List<HRegionInfo> regions) throws InterruptedException {
     int waitTime = this.server.getConfiguration().getInt(
         "hbase.bulk.waitbetween.reopen", 0);
     RegionStates regionStates = assignmentManager.getRegionStates();
     for (HRegionInfo region : regions) {
       if (server.isStopped()) {
         return;
       }
       if (regionStates.isRegionInTransition(region)) {
         continue;
       }
       assignmentManager.unassign(region, false);
       while (regionStates.isRegionInTransition(region)
           && !server.isStopped()) {
         regionStates.waitForUpdate(100);
       }
       if (waitTime > 0 && !server.isStopped()) {
         Thread.sleep(waitTime);
       }
     }
   }
 }