/*
* Copyright (c) 2011-2018 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.
Comparator;
import java.util.
Queue;
import java.util.function.
Supplier;
import reactor.core.
CoreSubscriber;
import reactor.core.
Scannable;
import reactor.util.annotation.
Nullable;
/**
* Merges the individual 'rails' of the source {@link ParallelFlux} assuming a total order
* of the values, by picking the smallest available value from each rail, resulting in
* a single regular Publisher sequence (exposed as a {@link Flux}).
*
* @param <T> the value type
* @author Simon Baslé
*/
final class
ParallelMergeOrdered<T> extends
Flux<T> implements
Scannable {
final
ParallelFlux<? extends T>
source;
final int
prefetch;
final
Supplier<
Queue<T>>
queueSupplier;
final
Comparator<? super T>
valueComparator;
ParallelMergeOrdered(
ParallelFlux<? extends T>
source, int
prefetch,
Supplier<
Queue<T>>
queueSupplier,
Comparator<? super T>
valueComparator) {
if (
prefetch <= 0) {
throw new
IllegalArgumentException("prefetch > 0 required but it was " +
prefetch);
}
this.
source =
source;
this.
prefetch =
prefetch;
this.
queueSupplier =
queueSupplier;
this.
valueComparator =
valueComparator;
}
@
Override
public int
getPrefetch() {
return
prefetch;
}
@
Override
@
Nullable
public
Object scanUnsafe(
Attr key) {
if (
key ==
Attr.
PARENT) return
source;
if (
key ==
Attr.
PREFETCH) return
prefetch;
return null;
}
@
Override
public void
subscribe(
CoreSubscriber<? super T>
actual) {
FluxMergeOrdered.
MergeOrderedMainProducer<T>
main = new
FluxMergeOrdered.
MergeOrderedMainProducer<>(
actual,
valueComparator,
prefetch,
source.
parallelism());
actual.
onSubscribe(
main);
source.
subscribe(
main.
subscribers);
}
}