| /** |
| * 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.util.ArrayList; |
| import java.util.HashMap; |
| import java.util.LinkedList; |
| import java.util.List; |
| import java.util.Map; |
| import java.util.Queue; |
| import java.util.concurrent.Semaphore; |
| |
| public class KeyedRoundRobinQueue<V> { |
| private final Object lock = new Object(); |
| private Semaphore size = new Semaphore(0); |
| private Map<Object, Queue<V>> queues = new HashMap<>(); |
| private List<Object> keyOrder = new ArrayList<>(); |
| private int currIndex = 0; |
| |
| public void add(Object key, V val) { |
| synchronized (lock) { |
| Queue<V> queue = queues.get(key); |
| if (queue == null) { |
| queue = new LinkedList<>(); |
| queues.put(key, queue); |
| keyOrder.add(key); |
| } |
| queue.add(val); |
| } |
| size.release(); |
| } |
| |
| public V take() throws InterruptedException { |
| size.acquire(); |
| synchronized (lock) { |
| Object key = keyOrder.get(currIndex); |
| Queue<V> queue = queues.get(key); |
| V ret = queue.remove(); |
| if (queue.isEmpty()) { |
| keyOrder.remove(currIndex); |
| queues.remove(key); |
| if (keyOrder.size() == 0) { |
| currIndex = 0; |
| } else { |
| currIndex = currIndex % keyOrder.size(); |
| } |
| } else { |
| currIndex = (currIndex + 1) % keyOrder.size(); |
| } |
| return ret; |
| } |
| } |
| } |