Average in RxJava - reactive-programming

Question

I am trying to make a system resource monitor using Rx. I use a thread for observable which returns the CPU Usage every 1000 milliseconds. Now I want my subscriber to find the average of the CPU usage every 10 seconds.
public class seperate {
private ScheduledThreadPoolExecutor executorPool;
public void test()
{
Observable<Double> myObservable = Observable.create(
new Observable.OnSubscribe<Double>() {
#Override
public void call(Subscriber<? super Double> sub) {
executorPool = new ScheduledThreadPoolExecutor(9);
int timeout1 = 10;
TimerTask timeoutTimertask1=new MyTimerTasks(sub);
executorPool.scheduleAtFixedRate(timeoutTimertask1,timeout1, timeout1,
TimeUnit.MILLISECONDS);
// This returns the cpu usage every 10ms.
}
}
);
Subscriber<Double> mySubscriber = new Subscriber<Double>() {
#Override
public void onNext(Double s) { System.out.println(s); }
#Override
public void onCompleted() { }
#Override
public void onError(Throwable e) { }
};
myObservable.subscribe(mySubscriber);
}
}

Answer 1

You can use buffer or window to divide source emission into groups of items, then calculate average on each group.
Avarage is a part of rxjava-math library.
Moreover you can simplify your code using interval.
Below is example using window and interval:
Observable myObservable = Observable.interval(10, TimeUnit.MILLISECONDS)
.map(new Func1<Long, Double>() {
#Override
public Double call(Long aLong) {
Double d = 100.;//calculate CPU usage
return d;
}
})
.window(10, TimeUnit.SECONDS)
.flatMap(new Func1<Observable<Double>, Observable<Double>>() {
#Override
public Observable<Double> call(Observable<Double> windowObservable) {
return MathObservable.averageDouble(windowObservable);
}
});

Answer 2

Use MathObservable like so:
MathObservable.averageLong(longsObservable).subscribe(average -> Timber.d("average:%d", average));
More info can be found here:
https://github.com/ReactiveX/RxJava/wiki/Mathematical-and-Aggregate-Operators
Source Code:
https://github.com/ReactiveX/RxJavaMath