001/* 002 * Licensed to the Apache Software Foundation (ASF) under one 003 * or more contributor license agreements. See the NOTICE file 004 * distributed with this work for additional information 005 * regarding copyright ownership. The ASF licenses this file 006 * to you under the Apache License, Version 2.0 (the 007 * "License"); you may not use this file except in compliance 008 * with the License. You may obtain a copy of the License at 009 * 010 * http://www.apache.org/licenses/LICENSE-2.0 011 * 012 * Unless required by applicable law or agreed to in writing, 013 * software distributed under the License is distributed on an 014 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY 015 * KIND, either express or implied. See the License for the 016 * specific language governing permissions and limitations 017 * under the License. 018 */ 019package org.apache.reef.driver.task; 020 021import org.apache.reef.annotations.Provided; 022import org.apache.reef.annotations.audience.DriverSide; 023import org.apache.reef.annotations.audience.Public; 024import org.apache.reef.io.Message; 025import org.apache.reef.io.Numberable; 026import org.apache.reef.io.naming.Identifiable; 027 028/** 029 * A message from a running task to the driver. 030 */ 031@DriverSide 032@Public 033@Provided 034public interface TaskMessage extends Message, Identifiable, Numberable { 035 036 /** 037 * @return the message. 038 */ 039 @Override 040 byte[] get(); 041 042 /** 043 * @return the ID of the sending task. 044 */ 045 @Override 046 String getId(); 047 048 /** 049 * @return the sequence number of the message 050 * 051 * Terminology: a source sends a message to a target. 052 * Example sources are Tasks or Contexts. Example targets are Drivers. 053 * 054 * The method guarantees that sequence numbers increase strictly monotonically per message source. 055 * So numbers of messages from different sources should not be compared to each other. 056 * 057 * Clients of this method must not assume any particular method implementation 058 * because it may change in the future. 059 * 060 * The current implementation returns the timestamp of a heartbeat that contained the message. 061 * A heartbeat may contain several messages; all such message will get the same sequence number. 062 * A source can attach only one message to a single heartbeat, so the strict sequence number monotonicity 063 * per source is guaranteed. 064 * 065 */ 066 @Override 067 long getSequenceNumber(); 068 069 /** 070 * @return the id of the context the sending task is running in. 071 */ 072 String getContextId(); 073 074 /** 075 * @return the ID of the TaskMessageSource 076 */ 077 String getMessageSourceID(); 078}