hu.akarnokd.rxjava2.internal.operators.PublisherZipIterable Maven / Gradle / Ivy

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rxjava2-backport developed by David Karnok
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/**
 * Copyright 2015 David Karnok and Netflix, Inc.
 * 
 * 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 hu.akarnokd.rxjava2.internal.operators;

import java.util.Iterator;

import org.reactivestreams.*;

import hu.akarnokd.rxjava2.functions.BiFunction;
import hu.akarnokd.rxjava2.internal.subscriptions.*;
import hu.akarnokd.rxjava2.plugins.RxJavaPlugins;

public final class PublisherZipIterable implements Publisher {
    final Publisher source;
    final Iterable other;
    final BiFunction zipper;

    public PublisherZipIterable(
            Publisher source,
            Iterable other, BiFunction zipper) {
        this.source = source;
        this.other = other;
        this.zipper = zipper;
    }
    
    @Override
    public void subscribe(Subscriber t) {
        Iterator it;
        
        try {
            it = other.iterator();
        } catch (Throwable e) {
            EmptySubscription.error(e, t);
            return;
        }
        
        if (it == null) {
            EmptySubscription.error(new NullPointerException("The iterator returned by other is null"), t);
            return;
        }
        
        boolean b;
        
        try {
            b = it.hasNext();
        } catch (Throwable e) {
            EmptySubscription.error(e, t);
            return;
        }
        
        if (!b) {
            EmptySubscription.complete(t);
            return;
        }
        
        source.subscribe(new ZipIterableSubscriber(t, it, zipper));
    }
    
    static final class ZipIterableSubscriber implements Subscriber {
        final Subscriber actual;
        final Iterator iterator;
        final BiFunction zipper;
        
        Subscription s;
        
        boolean done;

        public ZipIterableSubscriber(Subscriber actual, Iterator iterator,
                BiFunction zipper) {
            this.actual = actual;
            this.iterator = iterator;
            this.zipper = zipper;
        }
        
        @Override
        public void onSubscribe(Subscription s) {
            if (SubscriptionHelper.validateSubscription(this.s, s)) {
                return;
            }
            this.s = s;
            actual.onSubscribe(s);
        }
        
        @Override
        public void onNext(T t) {
            if (done) {
                return;
            }

            U u;

            try {
                u = iterator.next();
            } catch (Throwable e) {
                error(e);
                return;
            }
            
            if (u == null) {
                error(new NullPointerException("The iterator returned a null value"));
                return;
            }
            
            V v;
            try {
                v = zipper.apply(t, u);
            } catch (Throwable e) {
                error(new NullPointerException("The iterator returned a null value"));
                return;
            }
            
            if (v == null) {
                error(new NullPointerException("The zipper function returned a null value"));
                return;
            }
            
            actual.onNext(v);
            
            boolean b;
            
            try {
                b = iterator.hasNext();
            } catch (Throwable e) {
                error(e);
                return;
            }
            
            if (!b) {
                done = true;
                s.cancel();
                actual.onComplete();
            }
        }
        
        void error(Throwable e) {
            done = true;
            s.cancel();
            actual.onError(e);
        }
        
        @Override
        public void onError(Throwable t) {
            if (done) {
                RxJavaPlugins.onError(t);
                return;
            }
            done = true;
            actual.onError(t);
        }
        
        @Override
        public void onComplete() {
            if (done) {
                return;
            }
            done = true;
            actual.onComplete();
        }
        
    }
}