1   /**
2    *
3    * Licensed to the Apache Software Foundation (ASF) under one
4    * or more contributor license agreements.  See the NOTICE file
5    * distributed with this work for additional information
6    * regarding copyright ownership.  The ASF licenses this file
7    * to you under the Apache License, Version 2.0 (the
8    * "License"); you may not use this file except in compliance
9    * with the License.  You may obtain a copy of the License at
10   *
11   *     http://www.apache.org/licenses/LICENSE-2.0
12   *
13   * Unless required by applicable law or agreed to in writing, software
14   * distributed under the License is distributed on an "AS IS" BASIS,
15   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
16   * See the License for the specific language governing permissions and
17   * limitations under the License.
18   */
19  package org.apache.hadoop.hbase.zookeeper;
20  
21  import org.apache.hadoop.classification.InterfaceAudience;
22  import org.apache.hadoop.hbase.Abortable;
23  import org.apache.hadoop.hbase.HRegionInfo;
24  
25  /**
26   * Tracks the unassigned zookeeper node used by the META table.
27   * <p>
28   * If META is already assigned when instantiating this class, you will not
29   * receive any notification for that assignment.  You will receive a
30   * notification after META has been successfully assigned to a new location.
31   */
32  @InterfaceAudience.Private
33  public class MetaNodeTracker extends ZooKeeperNodeTracker {
34    /**
35     * Creates a meta node tracker.
36     * @param watcher
37     * @param abortable
38     */
39    public MetaNodeTracker(final ZooKeeperWatcher watcher, final Abortable abortable) {
40      super(watcher, ZKUtil.joinZNode(watcher.assignmentZNode,
41          HRegionInfo.FIRST_META_REGIONINFO.getEncodedName()), abortable);
42    }
43  
44    @Override
45    public void nodeDeleted(String path) {
46      super.nodeDeleted(path);
47    }
48  }