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

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rxjava2-backport developed by David Karnok
There is a newer version: 2.0.0-RC3
/**
 * 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.concurrent.atomic.AtomicInteger;

import org.reactivestreams.*;

import hu.akarnokd.rxjava2.exceptions.CompositeException;
import hu.akarnokd.rxjava2.functions.Predicate;
import hu.akarnokd.rxjava2.internal.subscriptions.SubscriptionArbiter;

public final class PublisherRetryPredicate implements Publisher {
    final Publisher source;
    final Predicate predicate;
    final long count;
    public PublisherRetryPredicate(Publisher source, 
            long count,
            Predicate predicate) {
        this.source = source;
        this.predicate = predicate;
        this.count = count;
    }
    
    @Override
    public void subscribe(Subscriber s) {
        SubscriptionArbiter sa = new SubscriptionArbiter();
        s.onSubscribe(sa);
        
        RepeatSubscriber rs = new RepeatSubscriber(s, count, predicate, sa, source);
        rs.subscribeNext();
    }
    
    static final class RepeatSubscriber extends AtomicInteger implements Subscriber {
        /** */
        private static final long serialVersionUID = -7098360935104053232L;
        
        final Subscriber actual;
        final SubscriptionArbiter sa;
        final Publisher source;
        final Predicate predicate;
        long remaining;
        public RepeatSubscriber(Subscriber actual, long count, 
                Predicate predicate, SubscriptionArbiter sa, Publisher source) {
            this.actual = actual;
            this.sa = sa;
            this.source = source;
            this.predicate = predicate;
            this.remaining = count;
        }
        
        @Override
        public void onSubscribe(Subscription s) {
            sa.setSubscription(s);
        }
        
        @Override
        public void onNext(T t) {
            actual.onNext(t);
            sa.produced(1L);
        }
        @Override
        public void onError(Throwable t) {
            long r = remaining;
            if (r != Long.MAX_VALUE) {
                remaining = r - 1;
            }
            if (r == 0) {
                actual.onError(t);
            } else {
                boolean b;
                try {
                    b = predicate.test(t);
                } catch (Throwable e) {
                    actual.onError(new CompositeException(e, t));
                    return;
                }
                if (!b) {
                    actual.onError(t);
                    return;
                }
                subscribeNext();
            }
        }
        
        @Override
        public void onComplete() {
            actual.onComplete();
        }
        
        /**
         * Subscribes to the source again via trampolining.
         */
        void subscribeNext() {
            if (getAndIncrement() == 0) {
                int missed = 1;
                for (;;) {
                    if (sa.isCancelled()) {
                        return;
                    }
                    source.subscribe(this);
                    
                    missed = addAndGet(-missed);
                    if (missed == 0) {
                        break;
                    }
                }
            }
        }
    }
}