| /* |
| * 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.cassandra.scheduler; |
| |
| import java.util.concurrent.SynchronousQueue; |
| import java.util.concurrent.TimeoutException; |
| import java.util.concurrent.TimeUnit; |
| |
| import org.apache.cassandra.metrics.LatencyMetrics; |
| |
| class WeightedQueue |
| { |
| private final LatencyMetrics metric; |
| |
| public final String key; |
| public final int weight; |
| private final SynchronousQueue<Entry> queue; |
| public WeightedQueue(String key, int weight) |
| { |
| this.key = key; |
| this.weight = weight; |
| this.queue = new SynchronousQueue<Entry>(true); |
| this.metric = new LatencyMetrics("scheduler", "WeightedQueue", key); |
| } |
| |
| public void put(Thread t, long timeoutMS) throws InterruptedException, TimeoutException |
| { |
| if (!queue.offer(new WeightedQueue.Entry(t), timeoutMS, TimeUnit.MILLISECONDS)) |
| throw new TimeoutException("Failed to acquire request scheduler slot for '" + key + "'"); |
| } |
| |
| public Thread poll() |
| { |
| Entry e = queue.poll(); |
| if (e == null) |
| return null; |
| metric.addNano(System.nanoTime() - e.creationTime); |
| return e.thread; |
| } |
| |
| @Override |
| public String toString() |
| { |
| return "RoundRobinScheduler.WeightedQueue(key=" + key + " weight=" + weight + ")"; |
| } |
| |
| private final static class Entry |
| { |
| public final long creationTime = System.nanoTime(); |
| public final Thread thread; |
| public Entry(Thread thread) |
| { |
| this.thread = thread; |
| } |
| } |
| } |