/* * 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.utils; import java.util.Iterator; import java.util.NoSuchElementException; import java.util.concurrent.LinkedBlockingDeque; /** * bounded threadsafe deque */ public class BoundedStatsDeque implements Iterable<Double> { protected final LinkedBlockingDeque<Double> deque; public BoundedStatsDeque(int size) { deque = new LinkedBlockingDeque<Double>(size); } public Iterator<Double> iterator() { return deque.iterator(); } public int size() { return deque.size(); } public void clear() { deque.clear(); } public void add(double i) { if (!deque.offer(i)) { try { deque.remove(); } catch (NoSuchElementException e) { // oops, clear() beat us to it } deque.offer(i); } } public double sum() { double sum = 0d; for (Double interval : deque) { sum += interval; } return sum; } public double mean() { return size() > 0 ? sum() / size() : 0; } }