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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.ipc;
19  
20  import com.google.protobuf.Message;
21  import org.apache.hadoop.hbase.classification.InterfaceAudience;
22  import org.apache.hadoop.hbase.classification.InterfaceStability;
23  import org.apache.hadoop.hbase.HBaseInterfaceAudience;
24  import org.apache.hadoop.hbase.protobuf.generated.RPCProtos.RequestHeader;
25  import org.apache.hadoop.hbase.security.User;
26  
27  /**
28   * Function to figure priority of incoming request.
29   */
30  @InterfaceAudience.LimitedPrivate({HBaseInterfaceAudience.COPROC, HBaseInterfaceAudience.PHOENIX})
31  @InterfaceStability.Evolving
32  public interface PriorityFunction {
33    /**
34     * Returns the 'priority type' of the specified request.
35     * The returned value is mainly used to select the dispatch queue.
36     * @param header
37     * @param param
38     * @param user
39     * @return Priority of this request.
40     */
41    int getPriority(RequestHeader header, Message param, User user);
42  
43    /**
44     * Returns the deadline of the specified request.
45     * The returned value is used to sort the dispatch queue.
46     * @param header
47     * @param param
48     * @return Deadline of this request. 0 now, otherwise msec of 'delay'
49     */
50    long getDeadline(RequestHeader header, Message param);
51  }