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 * 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
 *
 *        https://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
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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 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 Flux).
Author:Simon Baslé
Type parameters:
  • <T> – the value type
/** * 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; if (key == Attr.RUN_STYLE) return Attr.RunStyle.SYNC; 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); } }