| /** |
| * 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.storm.utils; |
| |
| import java.io.Serializable; |
| import java.util.LinkedList; |
| import java.util.List; |
| import java.util.concurrent.LinkedBlockingQueue; |
| import java.util.concurrent.TimeUnit; |
| import java.util.concurrent.locks.Condition; |
| import java.util.concurrent.locks.ReentrantLock; |
| import org.apache.storm.multilang.BoltMsg; |
| |
| /** |
| * A data structure for ShellBolt which includes two queues (FIFO), which one is for task ids (unbounded), another one is for bolt msg |
| * (bounded). |
| */ |
| public class ShellBoltMessageQueue implements Serializable { |
| private final LinkedList<List<Integer>> taskIdsQueue = new LinkedList<>(); |
| private final LinkedBlockingQueue<BoltMsg> boltMsgQueue; |
| |
| private final ReentrantLock takeLock = new ReentrantLock(); |
| private final Condition notEmpty = takeLock.newCondition(); |
| |
| public ShellBoltMessageQueue(int boltMsgCapacity) { |
| if (boltMsgCapacity <= 0) { |
| throw new IllegalArgumentException(); |
| } |
| this.boltMsgQueue = new LinkedBlockingQueue<>(boltMsgCapacity); |
| } |
| |
| public ShellBoltMessageQueue() { |
| this(Integer.MAX_VALUE); |
| } |
| |
| /** |
| * put list of task id to its queue. |
| * |
| * @param taskIds task ids that received the tuples |
| */ |
| public void putTaskIds(List<Integer> taskIds) { |
| takeLock.lock(); |
| try { |
| taskIdsQueue.add(taskIds); |
| notEmpty.signal(); |
| } finally { |
| takeLock.unlock(); |
| } |
| } |
| |
| /** |
| * put bolt message to its queue. |
| * |
| * @param boltMsg BoltMsg to pass to subprocess |
| */ |
| public void putBoltMsg(BoltMsg boltMsg) throws InterruptedException { |
| boltMsgQueue.put(boltMsg); |
| takeLock.lock(); |
| try { |
| notEmpty.signal(); |
| } finally { |
| takeLock.unlock(); |
| } |
| } |
| |
| /** |
| * poll() is a core feature of ShellBoltMessageQueue. It retrieves and removes the head of one queues, waiting up to the specified wait |
| * time if necessary for an element to become available. There's priority that what queue it retrieves first, taskIds is higher than |
| * boltMsgQueue. |
| * |
| * @param timeout how long to wait before giving up, in units of unit |
| * @param unit a TimeUnit determining how to interpret the timeout parameter |
| * @return {@code List<Integer>} if task id is available, BoltMsg if task id is not available but bolt message is available, null if the |
| * specified waiting time elapses before an element is available. |
| */ |
| public Object poll(long timeout, TimeUnit unit) throws InterruptedException { |
| takeLock.lockInterruptibly(); |
| long nanos = unit.toNanos(timeout); |
| try { |
| // wait for available queue |
| while (taskIdsQueue.peek() == null && boltMsgQueue.peek() == null) { |
| if (nanos <= 0) { |
| return null; |
| } |
| nanos = notEmpty.awaitNanos(nanos); |
| } |
| |
| // taskIds first |
| List<Integer> taskIds = taskIdsQueue.peek(); |
| if (taskIds != null) { |
| taskIds = taskIdsQueue.poll(); |
| return taskIds; |
| } |
| |
| // boltMsgQueue should have at least one entry at the moment |
| return boltMsgQueue.poll(); |
| } finally { |
| takeLock.unlock(); |
| } |
| } |
| |
| } |