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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  
21  package org.apache.hadoop.hbase.regionserver;
22  
23  /**
24   * Implementors of this interface want to be notified when an HRegion
25   * determines that a cache flush is needed. A FlushRequester (or null)
26   * must be passed to the HRegion constructor so it knows who to call when it
27   * has a filled memstore.
28   */
29  public interface FlushRequester {
30    /**
31     * Tell the listener the cache needs to be flushed.
32     *
33     * @param region the HRegion requesting the cache flush
34     */
35    void request(HRegion region);
36  }