io.github.pellse.assembler.flux.FluxAdapter Maven / Gradle / Ivy

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/*
 * Copyright 2018 Sebastien Pelletier
 *
 * 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.github.pellse.assembler.flux;

import io.github.pellse.assembler.AssemblerAdapter;
import org.reactivestreams.Publisher;
import reactor.core.publisher.Flux;
import reactor.core.scheduler.Scheduler;

import java.util.List;
import java.util.Map;
import java.util.function.Function;
import java.util.function.Supplier;
import java.util.stream.Stream;

import static java.util.Objects.requireNonNull;
import static java.util.stream.Collectors.toList;
import static reactor.core.publisher.Mono.fromSupplier;
import static reactor.core.scheduler.Schedulers.parallel;

public class FluxAdapter implements AssemblerAdapter> {

    private final Scheduler scheduler;

    private FluxAdapter(Scheduler scheduler) {
        this.scheduler = requireNonNull(scheduler);
    }

    @SuppressWarnings("unchecked")
    @Override
    public Flux convertMapperSources(Stream>> mapperSources,
                                        Function>, Stream> domainObjectStreamBuilder) {

        List>> publishers = mapperSources
                .map(mappingSupplier -> fromSupplier(mappingSupplier).subscribeOn(scheduler))
                .collect(toList());

        return Flux.zip(publishers,
                mapperResults -> domainObjectStreamBuilder.apply(Stream.of(mapperResults)
                        .map(mapResult -> (Map) mapResult)
                        .collect(toList())))
                .flatMap(Flux::fromStream);
    }

    public static  FluxAdapter fluxAdapter() {
        return fluxAdapter(parallel());
    }

    public static  FluxAdapter fluxAdapter(Scheduler scheduler) {
        return new FluxAdapter<>(scheduler);
    }
}