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.driver.ContextSubmittable; 025import org.apache.reef.driver.TaskSubmittable; 026import org.apache.reef.io.naming.Identifiable; 027import org.apache.reef.tang.Configuration; 028 029/** 030 * Represents an active context on an Evaluator. 031 * <p> 032 * A context consists of two configurations: 033 * <ol> 034 * <li>ContextConfiguration: Its visibility is limited to the context itself and tasks spawned from it.</li> 035 * <li>ServiceConfiguration: This is "inherited" by child context spawned.</li> 036 * </ol> 037 * <p> 038 * Contexts have identifiers. A context is instantiated on a single Evaluator. Contexts are either created on an 039 * AllocatedEvaluator (for what is called the "root Context") or by forming sub-Contexts. 040 * <p> 041 * Contexts form a stack. Only the topmost context is active. Child Contexts or Tasks can be submitted to the 042 * active Context. Contexts can be closed, in which case their parent becomes active. 043 * In the case of the root context, closing is equivalent to releasing the Evaluator. A child context "sees" all 044 * Configuration in its parent Contexts. 045 */ 046@Public 047@DriverSide 048@Provided 049public interface ActiveContext extends Identifiable, AutoCloseable, ContextBase, TaskSubmittable, ContextSubmittable { 050 051 @Override 052 void close(); 053 054 @Override 055 void submitTask(final Configuration taskConf); 056 057 @Override 058 void submitContext(final Configuration contextConfiguration); 059 060 @Override 061 void submitContextAndService(final Configuration contextConfiguration, final Configuration serviceConfiguration); 062 063 /** 064 * Send the active context the message, which will be delivered to all registered 065 * {@link org.apache.reef.evaluator.context.ContextMessageHandler}, for this context. 066 * 067 * @param message The message to be sent. 068 */ 069 void sendMessage(final byte[] message); 070 071}