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package rx.operators; | |
import java.util.ArrayDeque; | |
import java.util.ArrayList; | |
import java.util.Arrays; | |
import java.util.Comparator; | |
import java.util.Deque; | |
import java.util.List; | |
import java.util.concurrent.atomic.AtomicInteger; | |
import rx.Observable; | |
import rx.Observable.OnSubscribe; | |
import rx.Subscriber; | |
import rx.Subscription; | |
import rx.functions.Action0; | |
import rx.functions.Action1; | |
import rx.observers.SerializedSubscriber; | |
import rx.subjects.PublishSubject; | |
import rx.subscriptions.CompositeSubscription; | |
public class OrderedMerge<T> implements OnSubscribe<T> { | |
private final List<? extends Observable<? extends T>> sources; | |
private final Comparator<? super T> comparator; | |
final NotificationLite<T> nl = NotificationLite.instance(); | |
public OrderedMerge(List<? extends Observable<? extends T>> sources, Comparator<? super T> comparator) { | |
this.sources = sources; | |
this.comparator = comparator; | |
} | |
@Override | |
public void call(Subscriber<? super T> child) { | |
CompositeSubscription csub = new CompositeSubscription(); | |
child.add(csub); | |
List<SourceSubscriber> sourceSubscribers = new ArrayList<SourceSubscriber>(sources.size() + 1); | |
Merger merger = new Merger(sourceSubscribers, csub, new SerializedSubscriber<T>(child)); | |
for (int i = 0; i < sources.size(); i++) { | |
SourceSubscriber srcSub = new SourceSubscriber(merger); | |
csub.add(srcSub); | |
sourceSubscribers.add(srcSub); | |
} | |
int i = 0; | |
for (Observable<? extends T> source : sources) { | |
if (!child.isUnsubscribed()) { | |
source.subscribe(sourceSubscribers.get(i)); | |
} | |
i++; | |
} | |
} | |
final class Merger { | |
final List<SourceSubscriber> sourceSubscribers; | |
final Subscriber<? super T> child; | |
final Subscription cancel; | |
final AtomicInteger wip; | |
public Merger(List<SourceSubscriber> sourceSubscribers, Subscription cancel, Subscriber<? super T> child) { | |
this.sourceSubscribers = sourceSubscribers; | |
this.child = child; | |
this.cancel = cancel; | |
this.wip = new AtomicInteger(); | |
} | |
public void next() { | |
if (wip.getAndIncrement() == 0) { | |
outer: | |
do { | |
do { | |
T candidate = null; | |
int i = 0; | |
int candidateIndex = -1; | |
for (SourceSubscriber srcSub : sourceSubscribers) { | |
T o = srcSub.peek(); | |
if (!srcSub.done && o == null) { | |
continue outer; | |
} | |
if (candidate == null || (o != null && comparator.compare(o, candidate) < 0)) { | |
candidate = o; | |
candidateIndex = i; | |
} | |
i++; | |
} | |
if (candidate == null) { | |
child.onCompleted(); | |
} else { | |
sourceSubscribers.get(candidateIndex).poll(); | |
try { | |
child.onNext(candidate); | |
} catch (Throwable e) { | |
error(e); | |
return; | |
} | |
} | |
} while (!child.isUnsubscribed()); | |
} while (wip.decrementAndGet() > 0); | |
} | |
} | |
public void error(Throwable t) { | |
try { | |
child.onError(t); | |
} finally { | |
cancel.unsubscribe(); | |
} | |
} | |
} | |
final class SourceSubscriber extends Subscriber<T> { | |
final Deque<T> queue = new ArrayDeque<T>(); | |
final Merger merger; | |
volatile boolean done; | |
public SourceSubscriber(Merger merger) { | |
this.merger = merger; | |
} | |
public synchronized T peek() { | |
return queue.peek(); | |
} | |
public synchronized T poll() { | |
return queue.poll(); | |
} | |
@Override | |
public void onNext(T t) { | |
synchronized (this) { | |
queue.add(t); | |
} | |
merger.next(); | |
} | |
@Override | |
public void onError(Throwable e) { | |
merger.error(e); | |
} | |
@Override | |
public void onCompleted() { | |
done = true; | |
merger.next(); | |
} | |
} | |
public static void main(String[] args) { | |
PublishSubject<Integer> one = PublishSubject.create(); | |
PublishSubject<Integer> two = PublishSubject.create(); | |
Observable<Integer> merged = Observable.create(new OrderedMerge<Integer>(Arrays.asList(one, two), new Comparator<Integer>() { | |
@Override | |
public int compare(Integer o1, Integer o2) { | |
return o1.compareTo(o2); | |
} | |
})); | |
merged.subscribe(new Action1<Integer>() { | |
@Override | |
public void call(Integer t1) { | |
System.out.println(t1); | |
} | |
}, new Action1<Throwable>() { | |
@Override | |
public void call(Throwable t1) { | |
t1.printStackTrace(); | |
} | |
}, new Action0() { | |
@Override | |
public void call() { | |
System.out.println("Done"); | |
} | |
}); | |
System.out.println("One: 1"); | |
one.onNext(1); | |
System.out.println("One: 3"); | |
one.onNext(3); | |
System.out.println("One: 5"); | |
one.onNext(5); | |
System.out.println("Two: 2"); | |
two.onNext(2); | |
System.out.println("Two: 4"); | |
two.onNext(4); | |
System.out.println("Two: 6"); | |
two.onNext(6); | |
System.out.println("One: 7!"); | |
one.onNext(7); | |
one.onCompleted(); | |
System.out.println("Two: 8"); | |
two.onNext(8); | |
System.out.println("Two: 10!"); | |
two.onNext(10); | |
two.onCompleted(); | |
} | |
} |
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