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1   /**
2    * Licensed to the Apache Software Foundation (ASF) under one
3    * or more contributor license agreements.  See the NOTICE file
4    * distributed with this work for additional information
5    * regarding copyright ownership.  The ASF licenses this file
6    * to you under the Apache License, Version 2.0 (the
7    * "License"); you may not use this file except in compliance
8    * with the License.  You may obtain a copy of the License at
9    *
10   *     http://www.apache.org/licenses/LICENSE-2.0
11   *
12   * Unless required by applicable law or agreed to in writing, software
13   * distributed under the License is distributed on an "AS IS" BASIS,
14   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
15   * See the License for the specific language governing permissions and
16   * limitations under the License.
17   */
18  package org.apache.hadoop.hbase.master.cleaner;
19  
20  import org.apache.hadoop.hbase.classification.InterfaceAudience;
21  
22  /**
23   * Base class for the hfile cleaning function inside the master. By default, only the
24   * {@link TimeToLiveHFileCleaner} is called.
25   * <p>
26   * If other effects are needed, implement your own LogCleanerDelegate and add it to the
27   * configuration "hbase.master.hfilecleaner.plugins", which is a comma-separated list of fully
28   * qualified class names. The <code>HFileCleaner</code> will build the cleaner chain in 
29   * order the order specified by the configuration.
30   * </p>
31   * <p>
32   * For subclasses, setConf will be called exactly <i>once</i> before using the cleaner.
33   * </p>
34   * <p>
35   * Since {@link BaseHFileCleanerDelegate HFileCleanerDelegates} are created in
36   * HFileCleaner by reflection, classes that implements this interface <b>must</b>
37   * provide a default constructor.
38   * </p>
39   */
40  @InterfaceAudience.Private
41  public abstract class BaseHFileCleanerDelegate extends BaseFileCleanerDelegate {
42  
43    private boolean stopped = false;
44  
45    @Override
46    public void stop(String why) {
47      this.stopped = true;
48    }
49  
50    @Override
51    public boolean isStopped() {
52      return this.stopped;
53    }
54  }