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 org.apache.hadoop.hbase.classification.InterfaceAudience;
21 import org.apache.hadoop.hbase.classification.InterfaceStability;
22 import org.apache.hadoop.hbase.HBaseInterfaceAudience;
23
24 import java.io.IOException;
25 import java.net.InetSocketAddress;
26
27 /**
28 * An interface for RPC request scheduling algorithm.
29 */
30 @InterfaceAudience.LimitedPrivate({HBaseInterfaceAudience.COPROC, HBaseInterfaceAudience.PHOENIX})
31 @InterfaceStability.Evolving
32 public abstract class RpcScheduler {
33
34 /** Exposes runtime information of a {@code RpcServer} that a {@code RpcScheduler} may need. */
35 public static abstract class Context {
36 public abstract InetSocketAddress getListenerAddress();
37 }
38
39 /**
40 * Does some quick initialization. Heavy tasks (e.g. starting threads) should be
41 * done in {@link #start()}. This method is called before {@code start}.
42 *
43 * @param context provides methods to retrieve runtime information from
44 */
45 public abstract void init(Context context);
46
47 /**
48 * Prepares for request serving. An implementation may start some handler threads here.
49 */
50 public abstract void start();
51
52 /** Stops serving new requests. */
53 public abstract void stop();
54
55 /**
56 * Dispatches an RPC request asynchronously. An implementation is free to choose to process the
57 * request immediately or delay it for later processing.
58 *
59 * @param task the request to be dispatched
60 */
61 public abstract boolean dispatch(CallRunner task) throws IOException, InterruptedException;
62
63 /** Retrieves length of the general queue for metrics. */
64 public abstract int getGeneralQueueLength();
65
66 /** Retrieves length of the priority queue for metrics. */
67 public abstract int getPriorityQueueLength();
68
69 /** Retrieves length of the replication queue for metrics. */
70 public abstract int getReplicationQueueLength();
71
72 /** Retrieves the number of active handler. */
73 public abstract int getActiveRpcHandlerCount();
74 }