| 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 java.util.concurrent.BlockingQueue; |
| |
| import org.apache.helix.controller.stages.ClusterEvent; |
| import org.apache.helix.controller.stages.ClusterEventType; |
| import org.slf4j.Logger; |
| import org.slf4j.LoggerFactory; |
| |
| /** |
| * A blocking queue of ClusterEvent objects to be used by the controller pipeline. This prevents |
| * multiple events of the same type from flooding the controller and preventing progress from being |
| * made. This queue has no capacity. This class is meant to be a limited implementation of the |
| * {@link BlockingQueue} interface. |
| * |
| * This class is deprecated, please use {@link org.apache.helix.common.DedupEventBlockingQueue}. |
| */ |
| @Deprecated |
| public class ClusterEventBlockingQueue { |
| private static final Logger LOG = LoggerFactory.getLogger(ClusterEventBlockingQueue.class); |
| |
| private DedupEventBlockingQueue<ClusterEventType, ClusterEvent> _eventQueue; |
| |
| /** |
| * Instantiate the queue |
| */ |
| public ClusterEventBlockingQueue() { |
| _eventQueue = new DedupEventBlockingQueue(); |
| } |
| |
| /** |
| * Remove all events from the queue |
| */ |
| public void clear() { |
| _eventQueue.clear(); |
| } |
| |
| /** |
| * Add a single event to the queue, overwriting events with the same name |
| * @param event ClusterEvent event to add |
| */ |
| public void put(ClusterEvent event) { |
| _eventQueue.put(event.getEventType(), event); |
| if (LOG.isDebugEnabled()) { |
| LOG.debug("Putting event " + event.getEventType()); |
| LOG.debug("Event queue size: " + _eventQueue.size()); |
| } |
| } |
| |
| /** |
| * Remove an element from the front of the queue, blocking if none is available. This method |
| * will return the most recent event seen with the oldest enqueued event name. |
| * @return ClusterEvent at the front of the queue |
| * @throws InterruptedException if the wait for elements was interrupted |
| */ |
| public ClusterEvent take() throws InterruptedException { |
| ClusterEvent event = _eventQueue.take(); |
| if (event != null) { |
| LOG.debug("Taking event " + event.getEventType()); |
| LOG.debug("Event queue size: " + _eventQueue.size()); |
| } |
| return event; |
| } |
| |
| /** |
| * Get at the head of the queue without removing it |
| * @return ClusterEvent at the front of the queue, or null if none available |
| */ |
| public ClusterEvent peek() { |
| return _eventQueue.peek(); |
| } |
| |
| /** |
| * Get the queue size |
| * @return integer size of the queue |
| */ |
| public int size() { |
| return _eventQueue.size(); |
| } |
| |
| /** |
| * Check if the queue is empty |
| * @return true if events are not present, false otherwise |
| */ |
| public boolean isEmpty() { |
| return _eventQueue.isEmpty(); |
| } |
| } |