/*
* Copyright (c) 2011-2017 Pivotal Software Inc, All Rights Reserved.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package reactor.core.publisher;
import java.util.Iterator;
import java.util.Objects;
import org.reactivestreams.Publisher;
import org.reactivestreams.Subscriber;
/**
* Given a set of source Publishers the values of that Publisher is forwarded to the
* actual which responds first with any signal.
*
* @param <T> the value type
*
* @see <a href="https://github.com/reactor/reactive-streams-commons">Reactive-Streams-Commons</a>
*/
final class MonoFirst<T> extends Mono<T> {
final Mono<? extends T>[] array;
final Iterable<? extends Mono<? extends T>> iterable;
@SafeVarargs
MonoFirst(Mono<? extends T>... array) {
this.array = Objects.requireNonNull(array, "array");
this.iterable = null;
}
MonoFirst(Iterable<? extends Mono<? extends T>> iterable) {
this.array = null;
this.iterable = Objects.requireNonNull(iterable);
}
Mono<T> orAdditionalSource(Mono<? extends T> other) {
if (array != null) {
int n = array.length;
@SuppressWarnings("unchecked") Mono<? extends T>[] newArray = new Mono[n + 1];
System.arraycopy(array, 0, newArray, 0, n);
newArray[n] = other;
return new MonoFirst<>(newArray);
}
return null;
}
@SuppressWarnings("unchecked")
@Override
//TODO mutualize with FluxFirstEmitting
public void subscribe(Subscriber<? super T> s) {
Publisher<? extends T>[] a = array;
int n;
if (a == null) {
n = 0;
a = new Publisher[8];
Iterator<? extends Publisher<? extends T>> it;
try {
it = Objects.requireNonNull(iterable.iterator(), "The iterator returned is null");
}
catch (Throwable e) {
Operators.error(s, Operators.onOperatorError(e));
return;
}
for (; ; ) {
boolean b;
try {
b = it.hasNext();
}
catch (Throwable e) {
Operators.error(s, Operators.onOperatorError(e));
return;
}
if (!b) {
break;
}
Publisher<? extends T> p;
try {
p = Objects.requireNonNull(it.next(),
"The Publisher returned by the iterator is null");
}
catch (Throwable e) {
Operators.error(s, Operators.onOperatorError(e));
return;
}
if (n == a.length) {
Publisher<? extends T>[] c = new Publisher[n + (n >> 2)];
System.arraycopy(a, 0, c, 0, n);
a = c;
}
a[n++] = p;
}
}
else {
n = a.length;
}
if (n == 0) {
Operators.complete(s);
return;
}
if (n == 1) {
Publisher<? extends T> p = a[0];
if (p == null) {
Operators.error(s,
Operators.onOperatorError(new NullPointerException("The single source Publisher is null")));
}
else {
p.subscribe(s);
}
return;
}
FluxFirstEmitting.RaceCoordinator<T> coordinator =
new FluxFirstEmitting.RaceCoordinator<>(n);
coordinator.subscribe(a, n, s);
}
}