原子操作 [英] AtomicLong operations

问题描述

我需要执行以下操作：

  //平均，总计，已过的是Long的
 
 average =（（total * average）+ elapsed）/（++ total）;但是我想使用 AtomicLong   
 p> 
 
 
这是我想要的，但我不太会得到，如果是正确的：
  average.set（（（total.get（）* average.get（））+ elapsed）/ total.getAndIncrement（））; 
  
如何判断这是否正确？
解决方案
据推测，您正在使用AtomicLong，因为这些数字正在同时访问。因为你有两个数字，你在同一个语句中使用get和incrementAndGet，我不认为AtomicLong是正确的选择。
 
 
 
我发现AtomicXXX在许多情况下非常有帮助。但在这里，我想你需要做的艰难的方式。让你的数字简单的长私有变量，创建一个保护对象，然后确保在任何时候访问数字的同步保护对象。
 
 
 
我认为你唯一可以确定这些操作是真正原子的方式。
 
I need to perform the following operation: 
// average, total, elapsed are Long's

average = ( ( total * average ) + elapsed ) / (++total);
But I want to use AtomicLong

This is what I'm trying but I don't quite get if it is correct: 
 average.set( (( total.get() * average.get() ) + elapsed) / total.getAndIncrement() );
How can I tell if this is correct?
解决方案
Presumably you are using AtomicLong because these numbers are being accessed concurrently.  Since you have two numbers involved and you are using both a get and incrementAndGet in the same statement, I don't think AtomicLong is the right choice.

I have found AtomicXXX to be very helpful in many situations.  But here, I think you need to do it the hard way.  Make your numbers simple "long" private variables, create a guard object, then make sure to synchronize on the guard object any time you access the numbers.

I think that is the only way you can be certain that these operations are truly atomic.

                        
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