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