| package org.apache.helix.common; |
| |
| /* |
| * 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. |
| */ |
| |
| import org.apache.helix.zookeeper.zkclient.exception.ZkInterruptedException; |
| import org.slf4j.Logger; |
| import org.slf4j.LoggerFactory; |
| |
| /** |
| * A generic extended single-thread class to handle event with events with the same type de-duplicated (multiple-producer/single consumer |
| * style). |
| * |
| * T -- Type of the event. |
| * E -- The event itself. |
| */ |
| public abstract class DedupEventProcessor<T, E> extends Thread { |
| private static final Logger logger = LoggerFactory.getLogger(DedupEventProcessor.class); |
| |
| protected final DedupEventBlockingQueue<T, E> _eventQueue; |
| protected final String _clusterName; |
| protected final String _processorName; |
| |
| public DedupEventProcessor(String processorName) { |
| this(new String(), processorName); |
| } |
| |
| public DedupEventProcessor(String clusterName, String processorName) { |
| super(processorName + "-" + clusterName); |
| _processorName = processorName; |
| _eventQueue = new DedupEventBlockingQueue<>(); |
| _clusterName = clusterName; |
| } |
| |
| public DedupEventProcessor() { |
| this(new String(), "Default-DedupEventProcessor"); |
| } |
| |
| @Override |
| public void run() { |
| logger.info("START " + _processorName + " thread for cluster " + _clusterName); |
| while (!isInterrupted()) { |
| try { |
| E event = _eventQueue.take(); |
| handleEvent(event); |
| } catch (InterruptedException e) { |
| logger.warn(_processorName + " thread interrupted", e); |
| interrupt(); |
| } catch (ZkInterruptedException e) { |
| logger.warn(_processorName + " thread caught a ZK connection interrupt", e); |
| interrupt(); |
| } catch (ThreadDeath death) { |
| throw death; |
| } catch (Throwable t) { |
| logger.error(_processorName + " thread failed while running " + _processorName, t); |
| } |
| } |
| logger.info("END " + _processorName + " thread for cluster " + _clusterName); |
| } |
| |
| protected abstract void handleEvent(E event); |
| |
| public void queueEvent(T eventType, E event) { |
| if (isInterrupted()) { |
| return; |
| } |
| _eventQueue.put(eventType, event); |
| } |
| |
| public void resetEventQueue() { |
| _eventQueue.clear(); |
| } |
| |
| public void shutdown() { |
| this.interrupt(); |
| _eventQueue.clear(); |
| } |
| } |