| /** |
| * Licensed to the Apache Software Foundation (ASF) under one |
| * or more contributor license agreements. See the NOTICE file |
| * distributed with this work for additional information |
| * regarding copyright ownership. The ASF licenses this file |
| * to you under the Apache License, Version 2.0 (the |
| * "License"); you may not use this file except in compliance |
| * with the License. You may obtain a copy of the License at |
| * |
| * http://www.apache.org/licenses/LICENSE-2.0 |
| * |
| * Unless required by applicable law or agreed to in writing, |
| * software distributed under the License is distributed on an |
| * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY |
| * KIND, either express or implied. See the License for the |
| * specific language governing permissions and limitations |
| * under the License. |
| */ |
| package org.apache.apex.engine.api.plugin; |
| |
| import org.apache.apex.api.plugin.Plugin; |
| import org.apache.hadoop.classification.InterfaceStability; |
| |
| /** |
| * An Apex plugin is a user code which runs inside Stram. The interaction |
| * between plugin and Stram is managed by DAGExecutionPluginContext. Plugin can register to handle event in interest |
| * with callback handler using ${@link DAGExecutionPluginContext#register(DAGExecutionPluginContext.RegistrationType, DAGExecutionPluginContext.Handler)} |
| * |
| * Following events are supported |
| * <ul> |
| * <li>{@see DAGExecutionPluginContext.HEARTBEAT} The heartbeat from a container is delivered to the plugin after it has been handled by stram</li> |
| * <li>{@see DAGExecutionPluginContext.STRAM_EVENT} All the Stram event generated in Stram will be delivered to the plugin</li> |
| * <li>{@see DAGExecutionPluginContext.COMMIT_EVENT} When committedWindowId changes in the platform an event will be delivered to the plugin</li> |
| * </ul> |
| * |
| * A plugin should register a single handler for an event, In case multiple handlers are registered for an event, |
| * then the last registered handler will be used. Plugin should cleanup additional resources created by it during shutdown |
| * such as helper threads and open files. |
| */ |
| @InterfaceStability.Evolving |
| public interface DAGExecutionPlugin extends Plugin<DAGExecutionPluginContext> |
| { |
| } |