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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.namequeues;
21  
22  import org.apache.hadoop.hbase.classification.InterfaceAudience;
23  import org.apache.hadoop.hbase.namequeues.request.NamedQueueGetRequest;
24  import org.apache.hadoop.hbase.namequeues.response.NamedQueueGetResponse;
25  
26  /**
27   * In-memory Queue service provider for multiple use-cases. Implementers should be
28   * registered in LogEventHandler
29   */
30  @InterfaceAudience.Private
31  public interface NamedQueueService {
32  
33    /**
34     * Retrieve event type for NamedQueueService implementation.
35     *
36     * @return {@link NamedQueuePayload.NamedQueueEvent}
37     */
38    NamedQueuePayload.NamedQueueEvent getEvent();
39  
40    /**
41     * This implementation is generic for consuming records from LMAX
42     * disruptor and inserts records to EvictingQueue which is maintained by each
43     * ringbuffer provider.
44     *
45     * @param namedQueuePayload namedQueue payload from disruptor ring buffer
46     */
47    void consumeEventFromDisruptor(NamedQueuePayload namedQueuePayload);
48  
49    /**
50     * Cleans up queues maintained by services.
51     *
52     * @return true if slow log payloads are cleaned up, false otherwise
53     */
54    boolean clearNamedQueue();
55  
56    /**
57     * Retrieve in memory queue records from ringbuffer
58     *
59     * @param request namedQueue request with event type
60     * @return queue records from ringbuffer after filter (if applied)
61     */
62    NamedQueueGetResponse getNamedQueueRecords(NamedQueueGetRequest request);
63  
64    /**
65     * Add all in memory queue records to system table. The implementors can use system table
66     * or direct HDFS file or ZK as persistence system.
67     */
68    void persistAll();
69  }