package reactor.core.publisher;
import java.util.Objects;
import java.util.function.BiConsumer;
import java.util.function.Function;
import java.util.stream.Collector;
import org.reactivestreams.Subscription;
import reactor.core.CoreSubscriber;
import reactor.core.Fuseable;
import reactor.util.annotation.Nullable;
final class MonoStreamCollector<T, A, R> extends MonoFromFluxOperator<T, R>
implements Fuseable {
final Collector<? super T, A, ? extends R> collector;
MonoStreamCollector(Flux<? extends T> source,
Collector<? super T, A, ? extends R> collector) {
super(source);
this.collector = Objects.requireNonNull(collector, "collector");
}
@Override
public void subscribe(CoreSubscriber<? super R> actual) {
A container;
BiConsumer<? super A, ? super T> accumulator;
Function<? super A, ? extends R> finisher;
try {
container = collector.supplier()
.get();
accumulator = collector.accumulator();
finisher = collector.finisher();
}
catch (Throwable ex) {
Operators.error(actual, Operators.onOperatorError(ex, actual.currentContext()));
return;
}
source.subscribe(new StreamCollectorSubscriber<>(actual,
container,
accumulator,
finisher));
}
static final class StreamCollectorSubscriber<T, A, R>
extends Operators.MonoSubscriber<T, R> {
final BiConsumer<? super A, ? super T> accumulator;
final Function<? super A, ? extends R> finisher;
A container;
Subscription s;
boolean done;
StreamCollectorSubscriber(CoreSubscriber<? super R> actual,
A container,
BiConsumer<? super A, ? super T> accumulator,
Function<? super A, ? extends R> finisher) {
super(actual);
this.container = container;
this.accumulator = accumulator;
this.finisher = finisher;
}
@Override
@Nullable
public Object scanUnsafe(Attr key) {
if (key == Attr.TERMINATED) return done;
if (key == Attr.PARENT) return s;
return super.scanUnsafe(key);
}
@Override
public void onSubscribe(Subscription s) {
if (Operators.validate(this.s, s)) {
this.s = s;
actual.onSubscribe(this);
s.request(Long.MAX_VALUE);
}
}
@Override
public void onNext(T t) {
if (done) {
Operators.onNextDropped(t, actual.currentContext());
return;
}
try {
accumulator.accept(container, t);
}
catch (Throwable ex) {
onError(Operators.onOperatorError(s, ex, t, actual.currentContext()));
}
}
@Override
public void onError(Throwable t) {
if (done) {
Operators.onErrorDropped(t, actual.currentContext());
return;
}
done = true;
container = null;
actual.onError(t);
}
@Override
public void onComplete() {
if (done) {
return;
}
done = true;
A a = container;
container = null;
R r;
try {
r = finisher.apply(a);
}
catch (Throwable ex) {
actual.onError(Operators.onOperatorError(ex, actual.currentContext()));
return;
}
complete(r);
}
@Override
public void cancel() {
super.cancel();
s.cancel();
}
}
}