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 19 package org.apache.giraph.comm; 20 21 import java.io.IOException; 22 23 import org.apache.giraph.comm.flow_control.FlowControl; 24 import org.apache.giraph.comm.requests.WritableRequest; 25 import org.apache.hadoop.io.Writable; 26 27 /** 28 * Interface for master to send messages to workers 29 */ 30 public interface MasterClient { 31 /** 32 * Make sure that all the connections to workers have been established. 33 */ 34 void openConnections(); 35 36 /** 37 * Sends aggregator to its owner 38 * 39 * @param name Name of the object 40 * @param type Global communication type 41 * @param value Object value 42 * @throws IOException 43 */ 44 void sendToOwner(String name, GlobalCommType type, Writable value) 45 throws IOException; 46 47 /** 48 * Flush aggregated values cache. 49 */ 50 void finishSendingValues() throws IOException; 51 52 /** 53 * Flush all outgoing messages. This will synchronously ensure that all 54 * messages have been send and delivered prior to returning. 55 */ 56 void flush(); 57 58 /** 59 * Send a request to a remote server (should be already connected) 60 * 61 * @param destTaskId Destination worker id 62 * @param request Request to send 63 */ 64 void sendWritableRequest(int destTaskId, WritableRequest request); 65 66 /** 67 * Closes all connections. 68 */ 69 void closeConnections(); 70 71 /** 72 * Get the reference to the flow control policy used for sending requests 73 * 74 * @return reference to the flow control policy 75 */ 76 FlowControl getFlowControl(); 77 } 78