hanghangliu commented on code in PR #3539: URL: https://github.com/apache/gobblin/pull/3539#discussion_r964189902
########## gobblin-runtime/src/main/java/org/apache/gobblin/runtime/messaging/DynamicWorkUnitConsumer.java: ########## @@ -0,0 +1,83 @@ +/* + * 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.gobblin.runtime.messaging; + +import java.io.IOException; +import java.util.ArrayList; +import java.util.Collection; +import java.util.List; +import java.util.concurrent.ScheduledExecutorService; +import java.util.concurrent.TimeUnit; +import org.apache.gobblin.runtime.messaging.data.DynamicWorkUnitMessage; +import org.slf4j.Logger; +import org.slf4j.LoggerFactory; + + +/** + * Receives {@link DynamicWorkUnitMessage} sent by {@link DynamicWorkUnitProducer}. + * The class is responsible for fetching the messages from {@link MessageBuffer}. All business logic + * is done in the {@link DynamicWorkUnitMessage.Handler}.<br><br> + * + * This consumer can be used to poll a message buffer (e.g. HDFS or Kafka) using + * {@link ScheduledExecutorService#scheduleAtFixedRate(Runnable, long, long, TimeUnit)} to call the + * {@link Runnable#run()} method periodically in a background thread <br><br> + * + * Each new {@link DynamicWorkUnitMessage} is passed to a {@link DynamicWorkUnitMessage.Handler} + * and will call {@link DynamicWorkUnitMessage.Handler#handle(DynamicWorkUnitMessage)} + */ +public class DynamicWorkUnitConsumer implements Runnable { + private static final Logger LOG = LoggerFactory.getLogger(DynamicWorkUnitConsumer.class); + protected MessageBuffer<DynamicWorkUnitMessage> messageBuffer; + protected List<DynamicWorkUnitMessage.Handler> messageHandlers; + + public DynamicWorkUnitConsumer( + MessageBuffer<DynamicWorkUnitMessage> messageBuffer, + Collection<DynamicWorkUnitMessage.Handler> handlers) { + this.messageBuffer = messageBuffer; + this.messageHandlers = new ArrayList<DynamicWorkUnitMessage.Handler>(handlers); + } + + /** + * Fetches all unread messages sent by {@link DynamicWorkUnitProducer} and + * calls {@link DynamicWorkUnitMessage.Handler#handle(DynamicWorkUnitMessage)} method for each handler added via + * {@link DynamicWorkUnitConsumer#DynamicWorkUnitConsumer(MessageBuffer, Collection) + */ + public void run() { Review Comment: This run method will need to called in an infinite loop outside of the object. I'm thinking maybe using eventbus inside this consumer, and make the messageBuffer a runnable. Whenever the buffer receives a message, it post an event through the eventbus. In this case, within the buffer, pull or push based consumption can be seamless for the consumer. -- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. To unsubscribe, e-mail: [email protected] For queries about this service, please contact Infrastructure at: [email protected]
