Class DefaultSubscriber<T>

  • Type Parameters:
    T - the value type

    Example

    
     Flowable.range(1, 5)
         .subscribe(new DefaultSubscriber<Integer>() {
             @Override public void onStart() {
                 System.out.println("Start!");
                 request(1);
             }
             @Override public void onNext(Integer t) {
                 if (t == 3) {
                     cancel();
                 }
                 System.out.println(t);
                 request(1);
             }
             @Override public void onError(Throwable t) {
                 t.printStackTrace();
             }
             @Override public void onComplete() {
                 System.out.println("Done!");
             }
         });
     
    All Implemented Interfaces:
    FlowableSubscriber<T>, org.reactivestreams.Subscriber<T>
    Direct Known Subclasses:
    BlockingFlowableMostRecent.MostRecentSubscriber

    public abstract class DefaultSubscriber<T>
    extends java.lang.Object
    implements FlowableSubscriber<T>
    Abstract base implementation of a Subscriber with support for requesting via request(long), cancelling via via cancel() (both synchronously) and calls onStart() when the subscription happens.

    All pre-implemented final methods are thread-safe.

    The default onStart() requests Long.MAX_VALUE by default. Override the method to request a custom positive amount.

    Note that calling request(long) from onStart() may trigger an immediate, asynchronous emission of data to Subscriber.onNext(Object). Make sure all initialization happens before the call to request() in onStart(). Calling request(long) inside Subscriber.onNext(Object) can happen at any time because by design, onNext calls from upstream are non-reentrant and non-overlapping.

    Use the protected cancel() to cancel the sequence from within an onNext implementation.

    Like all other consumers, DefaultSubscriber can be subscribed only once. Any subsequent attempt to subscribe it to a new source will yield an IllegalStateException with message "It is not allowed to subscribe with a(n) <class name> multiple times.".

    Implementation of onStart(), Subscriber.onNext(Object), Subscriber.onError(Throwable) and Subscriber.onComplete() are not allowed to throw any unchecked exceptions. If for some reason this can't be avoided, use Flowable.safeSubscribe(org.reactivestreams.Subscriber) instead of the standard subscribe() method.

    • Field Summary

      Fields 
      Modifier and Type Field Description
      (package private) org.reactivestreams.Subscription upstream  
    • Method Summary

      All Methods Instance Methods Concrete Methods 
      Modifier and Type Method Description
      protected void cancel()
      Cancels the upstream's Subscription.
      protected void onStart()
      Called once the subscription has been set on this observer; override this to perform initialization or issue an initial request.
      void onSubscribe​(org.reactivestreams.Subscription s)
      Implementors of this method should make sure everything that needs to be visible in Subscriber.onNext(Object) is established before calling Subscription.request(long).
      protected void request​(long n)
      Requests from the upstream Subscription.
      • Methods inherited from class java.lang.Object

        clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
      • Methods inherited from interface org.reactivestreams.Subscriber

        onComplete, onError, onNext
    • Field Detail

      • upstream

        org.reactivestreams.Subscription upstream
    • Constructor Detail

      • DefaultSubscriber

        public DefaultSubscriber()
    • Method Detail

      • onSubscribe

        public final void onSubscribe​(org.reactivestreams.Subscription s)
        Description copied from interface: FlowableSubscriber
        Implementors of this method should make sure everything that needs to be visible in Subscriber.onNext(Object) is established before calling Subscription.request(long). In practice this means no initialization should happen after the request() call and additional behavior is thread safe in respect to onNext.
        Specified by:
        onSubscribe in interface FlowableSubscriber<T>
        Specified by:
        onSubscribe in interface org.reactivestreams.Subscriber<T>
      • request

        protected final void request​(long n)
        Requests from the upstream Subscription.
        Parameters:
        n - the request amount, positive
      • cancel

        protected final void cancel()
        Cancels the upstream's Subscription.
      • onStart

        protected void onStart()
        Called once the subscription has been set on this observer; override this to perform initialization or issue an initial request.

        The default implementation requests Long.MAX_VALUE.