Copyright (c) 2016-present, RxJava Contributors.
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.
/**
 * Copyright (c) 2016-present, RxJava Contributors.
 *
 * 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 io.reactivex.internal.operators.parallel;

import org.reactivestreams.*;

import io.reactivex.functions.Function;
import io.reactivex.internal.functions.ObjectHelper;
import io.reactivex.internal.operators.flowable.FlowableConcatMap;
import io.reactivex.internal.util.ErrorMode;
import io.reactivex.parallel.ParallelFlowable;

Concatenates the generated Publishers on each rail.
Type parameters:
<T> – the input value type
<R> – the output value type/**
 * Concatenates the generated Publishers on each rail.
 *
 * @param <T> the input value type
 * @param <R> the output value type
 */
public final class ParallelConcatMap<T, R> extends ParallelFlowable<R> {

    final ParallelFlowable<T> source;

    final Function<? super T, ? extends Publisher<? extends R>> mapper;

    final int prefetch;

    final ErrorMode errorMode;

    public ParallelConcatMap(
            ParallelFlowable<T> source,
            Function<? super T, ? extends Publisher<? extends R>> mapper,
                    int prefetch, ErrorMode errorMode) {
        this.source = source;
        this.mapper = ObjectHelper.requireNonNull(mapper, "mapper");
        this.prefetch = prefetch;
        this.errorMode = ObjectHelper.requireNonNull(errorMode, "errorMode");
    }

    @Override
    public int parallelism() {
        return source.parallelism();
    }

    @Override
    public void subscribe(Subscriber<? super R>[] subscribers) {
        if (!validate(subscribers)) {
            return;
        }

        int n = subscribers.length;

        @SuppressWarnings("unchecked")
        final Subscriber<T>[] parents = new Subscriber[n];

        for (int i = 0; i < n; i++) {
            parents[i] = FlowableConcatMap.subscribe(subscribers[i], mapper, prefetch, errorMode);
        }

        source.subscribe(parents);
    }
}