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1   /**
2    * Copyright 2010 The Apache Software Foundation
3    *
4    * Licensed to the Apache Software Foundation (ASF) under one
5    * or more contributor license agreements.  See the NOTICE file
6    * distributed with this work for additional information
7    * regarding copyright ownership.  The ASF licenses this file
8    * to you under the Apache License, Version 2.0 (the
9    * "License"); you may not use this file except in compliance
10   * with the License.  You may obtain a copy of the License at
11   *
12   *     http://www.apache.org/licenses/LICENSE-2.0
13   *
14   * Unless required by applicable law or agreed to in writing, software
15   * distributed under the License is distributed on an "AS IS" BASIS,
16   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
17   * See the License for the specific language governing permissions and
18   * limitations under the License.
19   */
20  package org.apache.hadoop.hbase.zookeeper;
21  
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  public class MetaNodeTracker extends ZooKeeperNodeTracker {
33    /**
34     * Creates a meta node tracker.
35     * @param watcher
36     * @param abortable
37     */
38    public MetaNodeTracker(final ZooKeeperWatcher watcher, final Abortable abortable) {
39      super(watcher, ZKUtil.joinZNode(watcher.assignmentZNode,
40          HRegionInfo.FIRST_META_REGIONINFO.getEncodedName()), abortable);
41    }
42  
43    @Override
44    public void nodeDeleted(String path) {
45      super.nodeDeleted(path);
46    }
47  }