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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  
20  package org.apache.hadoop.hbase.regionserver;
21  
22  import org.apache.hadoop.classification.InterfaceAudience;
23  
24  /**
25   * Request a flush.
26   */
27  @InterfaceAudience.Private
28  public interface FlushRequester {
29    /**
30     * Tell the listener the cache needs to be flushed.
31     *
32     * @param region the HRegion requesting the cache flush
33     */
34    void requestFlush(HRegion region);
35    /**
36     * Tell the listener the cache needs to be flushed after a delay
37     *
38     * @param region the HRegion requesting the cache flush
39     * @param delay after how much time should the flush happen
40     */
41    void requestDelayedFlush(HRegion region, long delay);
42  
43    /**
44     * Register a FlushRequestListener
45     * 
46     * @param listener
47     */
48    void registerFlushRequestListener(final FlushRequestListener listener);
49  
50    /**
51     * Unregister the given FlushRequestListener
52     * 
53     * @param listener
54     * @return true when passed listener is unregistered successfully.
55     */
56    public boolean unregisterFlushRequestListener(final FlushRequestListener listener);
57  
58    /**
59     * Sets the global memstore limit to a new size.
60     * 
61     * @param globalMemStoreSize
62     */
63    public void setGlobalMemstoreLimit(long globalMemStoreSize);
64  }