| /** |
| * 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 com.datatorrent.lib.appdata.query; |
| |
| import java.util.LinkedList; |
| import java.util.concurrent.Semaphore; |
| |
| import com.datatorrent.api.Context.OperatorContext; |
| import com.datatorrent.lib.appdata.QueueUtils.ConditionBarrier; |
| |
| /** |
| * This {@link QueueManager} functions like a standard {@link QueueManager}. Queries can be enqueued and when they are dequeued they are |
| * completely removed from the queue. |
| * @param <QUERY_TYPE> The type of the query to be enqueued in the queue. |
| * @param <META_QUERY> The type of the meta data to be enqueued with the query. |
| * @param <QUEUE_CONTEXT> The type of the queue context data. |
| * @since 3.0.0 |
| */ |
| public class SimpleQueueManager<QUERY_TYPE, META_QUERY, QUEUE_CONTEXT> |
| implements QueueManager<QUERY_TYPE, META_QUERY, QUEUE_CONTEXT> |
| { |
| private LinkedList<QueryBundle<QUERY_TYPE, META_QUERY, QUEUE_CONTEXT>> queue = new LinkedList<>(); |
| |
| private final Semaphore semaphore = new Semaphore(0); |
| private final ConditionBarrier conditionBarrier = new ConditionBarrier(); |
| |
| public SimpleQueueManager() |
| { |
| } |
| |
| @Override |
| public boolean enqueue(QUERY_TYPE query, META_QUERY metaQuery, QUEUE_CONTEXT queueContext) |
| { |
| conditionBarrier.gate(); |
| |
| QueryBundle<QUERY_TYPE, META_QUERY, QUEUE_CONTEXT> qq = new QueryBundle<>(query, metaQuery, queueContext); |
| |
| if (queue.offer(qq)) { |
| semaphore.release(); |
| return true; |
| } |
| |
| return false; |
| } |
| |
| @Override |
| public QueryBundle<QUERY_TYPE, META_QUERY, QUEUE_CONTEXT> dequeue() |
| { |
| return queue.poll(); |
| } |
| |
| @Override |
| public QueryBundle<QUERY_TYPE, META_QUERY, QUEUE_CONTEXT> dequeueBlock() |
| { |
| try { |
| semaphore.acquire(); |
| } catch (InterruptedException ex) { |
| throw new RuntimeException(ex); |
| } |
| |
| return queue.poll(); |
| } |
| |
| @Override |
| public void setup(OperatorContext context) |
| { |
| } |
| |
| @Override |
| public void beginWindow(long windowId) |
| { |
| } |
| |
| @Override |
| public void endWindow() |
| { |
| } |
| |
| @Override |
| public void teardown() |
| { |
| } |
| |
| @Override |
| public int getNumLeft() |
| { |
| return queue.size(); |
| } |
| |
| @Override |
| public void haltEnqueue() |
| { |
| conditionBarrier.lock(); |
| } |
| |
| @Override |
| public void resumeEnqueue() |
| { |
| conditionBarrier.unlock(); |
| } |
| } |