/*
* 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;
import java.util.concurrent.atomic.AtomicReference;
import com.google.common.util.concurrent.AtomicDouble;
/**
* bounded threadsafe deque
*/
public class BoundedStatsDeque implements Iterable<Double>
{
private final LinkedBlockingDeque<Double> deque;
private final AtomicDouble sum;
public BoundedStatsDeque(int size)
{
deque = new LinkedBlockingDeque<Double>(size);
sum = new AtomicDouble(0);
}
public Iterator<Double> iterator()
{
return deque.iterator();
}
public int size()
{
return deque.size();
}
public void add(double i)
{
if (!deque.offer(i))
{
Double removed = deque.remove();
sum.addAndGet(-removed);
deque.offer(i);
}
sum.addAndGet(i);
}
public double sum()
{
return sum.get();
}
public double mean()
{
return size() > 0 ? sum() / size() : 0;
}
}