/**
    * 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.util.Map;
  import java.util.concurrent.atomic.AtomicInteger;
  
  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.ServerName;
  import org.apache.hadoop.hbase.zookeeper.ZooKeeperWatcher;
  import org.apache.zookeeper.AsyncCallback.StringCallback;
  import org.apache.zookeeper.KeeperException;
  import org.apache.zookeeper.ZooKeeper;
  import org.apache.zookeeper.data.Stat;
  
  /**
   * Callback handler for creating unassigned offline znodes
   * used during bulk assign, async setting region to offline.
   */
  @InterfaceAudience.Private
  public class OfflineCallback implements StringCallback {
    private static final Log LOG = LogFactory.getLog(OfflineCallback.class);
    private final ExistCallback callBack;
    private final ZooKeeperWatcher zkw;
    private final ServerName destination;
    private final AtomicInteger counter;
  
    OfflineCallback(final ZooKeeperWatcher zkw,
        final ServerName destination, final AtomicInteger counter,
        final Map<String, Integer> offlineNodesVersions) {
      this.callBack = new ExistCallback(
        destination, counter, offlineNodesVersions);
      this.destination = destination;
      this.counter = counter;
      this.zkw = zkw;
    }
  
    @Override
    public void processResult(int rc, String path, Object ctx, String name) {
      if (rc == KeeperException.Code.NODEEXISTS.intValue()) {
        LOG.warn("Node for " + path + " already exists");
      } else if (rc != 0) {
        // This is result code.  If non-zero, need to resubmit.
        LOG.warn("rc != 0 for " + path + " -- retryable connectionloss -- " +
          "FIX see http://wiki.apache.org/hadoop/ZooKeeper/FAQ#A2");
        this.counter.addAndGet(1);
        return;
      }
  
      if (LOG.isDebugEnabled()) {
        LOG.debug("rs=" + ctx + ", server=" + destination);
      }
      // Async exists to set a watcher so we'll get triggered when
      // unassigned node changes.
      ZooKeeper zk = this.zkw.getRecoverableZooKeeper().getZooKeeper();
      zk.exists(path, this.zkw, callBack, ctx);
    }
  
    /**
     * Callback handler for the exists call that sets watcher on unassigned znodes.
     * Used during bulk assign on startup.
     */
    static class ExistCallback implements StatCallback {
      private static final Log LOG = LogFactory.getLog(ExistCallback.class);
      private final Map<String, Integer> offlineNodesVersions;
      private final AtomicInteger counter;
      private ServerName destination;
  
      ExistCallback(final ServerName destination,
          final AtomicInteger counter,
          final Map<String, Integer> offlineNodesVersions) {
        this.offlineNodesVersions = offlineNodesVersions;
        this.destination = destination;
        this.counter = counter;
      }
  
      @Override
      public void processResult(int rc, String path, Object ctx, Stat stat) {
        if (rc != 0) {
          // This is result code.  If non-zero, need to resubmit.
          LOG.warn("rc != 0 for " + path + " -- retryable connectionloss -- " +
           "FIX see http://wiki.apache.org/hadoop/ZooKeeper/FAQ#A2");
         this.counter.addAndGet(1);
         return;
       }
 
       if (LOG.isDebugEnabled()) {
         LOG.debug("rs=" + ctx + ", server=" + destination);
       }
       HRegionInfo region = ((RegionState)ctx).getRegion();
       offlineNodesVersions.put(
         region.getEncodedName(), Integer.valueOf(stat.getVersion()));
       this.counter.addAndGet(1);
     }
   }
 }