What is the maximum count and sum? Could the two fit into a 64 bit long? If
so a LongAccumulator could be made to work.
On Sat, 04 Jun 2022 at 01:53, Dain Ironfoot <vicvanda...@gmail.com> wrote:
> Hello,
>
> I am writing a class to calculate average of prices. We use it to generate
> buy/sell signal for some financial instruments therefore latency is
> crucial. Prices are sent via different threads therefore class needs to be
> thread-safe.
>
> Am I correct in understanding that I have to use a lock to make the two
> operations (adding and incrementing) atomic? I have looked at
> AtomicLong/LongAdder/LongAccumulator but looks like they can only sum the
> numbers atomically.
>
> *In other words, there is no way to do this in a lock-free manner? *
>
> Thank you!
>
>
>
> public final class Computer{
>
> private ReentrantReadWriteLock rwLock;
> private ReadLock readLock;
> private WriteLock writeLock;
>
> private BigDecimal sum;
> private int count;
>
> public AverageCalculatorThreadSafeImplementation2( ){
> this.rwLock = new ReentrantReadWriteLock();
> this.readLock = rwLock.readLock();
> this.writeLock = rwLock.writeLock();
> this.sum = new BigDecimal(0);
> }
>
> public final void add( double value ){
> writeLock.lock();
> try{
> sum = sum.add( BigDecimal.valueOf(value) );
> ++count;
> }finally{
> writeLock.unlock();
> }
> }
>
> public final double compute( ){
> readLock.lock();
> try{
> return sum.divide(BigDecimal.valueOf(count)).doubleValue();
> }finally{
> readLock.unlock();
> }
> }
>
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