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.context; 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 * Driver-side representation of a message sent by a Context to the Driver. 030 */ 031@Public 032@DriverSide 033@Provided 034public interface ContextMessage extends Message, Identifiable, Numberable { 035 036 /** 037 * @return the message sent by the Context. 038 */ 039 @Override 040 byte[] get(); 041 042 /** 043 * @return the ID of the sending Context. 044 */ 045 @Override 046 String getId(); 047 048 /** 049 * @return the ID of the ContextMessageSource that sent the message on the Context. 050 */ 051 String getMessageSourceID(); 052 053 /** 054 * @return the sequence number of the message 055 * 056 * Terminology: a source sends a message to a target. 057 * Example sources are Tasks or Contexts. Example targets are Drivers. 058 * 059 * The method guarantees that sequence numbers increase strictly monotonically per message source. 060 * So numbers of messages from different sources should not be compared to each other. 061 * 062 * Clients of this method must not assume any particular method implementation 063 * because it may change in the future. 064 * 065 * The current implementation returns the timestamp of a heartbeat that contained the message. 066 * A heartbeat may contain several messages; all such message will get the same sequence number. 067 * A source can attach only one message to a single heartbeat, so the strict sequence number monotonicity 068 * per source is guaranteed. 069 * 070 */ 071 @Override 072 long getSequenceNumber(); 073 074}