Class DisposableSubscriber<T>

java.lang.Object
io.reactivex.rxjava3.subscribers.DisposableSubscriber<T>
Type Parameters:
T - the received value type.
All Implemented Interfaces:
FlowableSubscriber<T>, Disposable, org.reactivestreams.Subscriber<T>
Direct Known Subclasses:
BlockingFlowableLatest.LatestSubscriberIterator, BlockingFlowableNext.NextSubscriber, FlowableBufferExactBoundary.BufferBoundarySubscriber, FlowableDebounce.DebounceSubscriber.DebounceInnerSubscriber, FlowableWindowBoundary.WindowBoundaryInnerSubscriber
public abstract class DisposableSubscriber<T> extends Object implements FlowableSubscriber<T>, Disposable
An abstract Subscriber that allows asynchronous, external cancellation by implementing Disposable.

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. Use the protected request(long) to request more items and cancel() to cancel the sequence from within an onNext implementation.

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.

Like all other consumers, DisposableSubscriber 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.

Example

Disposable d =
    Flowable.range(1, 5)
    .subscribeWith(new DisposableSubscriber<Integer>() {
        @Override public void onStart() {
            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!");
        }
    });
// ...
d.dispose();

  • Field Summary

    Fields
    Modifier and Type
    Field
    Description
    (package private) final AtomicReference<org.reactivestreams.Subscription>
    upstream
     

  • Constructor Summary

    Constructors
    Constructor
    Description
    DisposableSubscriber()
     

  • Method Summary

    Modifier and Type
    Method
    Description
    protected final void
    cancel()
    Cancels the Subscription set via onSubscribe(Subscription) or makes sure a Subscription set asynchronously (later) is cancelled immediately.
    final void
    dispose()
    Dispose the resource, the operation should be idempotent.
    final boolean
    isDisposed()
    Returns true if this resource has been disposed.
    protected void
    onStart()
    Called once the single upstream Subscription is set via onSubscribe(Subscription).
    final 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 final void
    request(long n)
    Requests the specified amount from the upstream if its Subscription is set via onSubscribe already.

    Methods inherited from class Object

    clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

    Methods inherited from interface org.reactivestreams.Subscriber

    onComplete, onError, onNext

  • Field Details

    • upstream

      final AtomicReference<org.reactivestreams.Subscription> upstream

  • Constructor Details

    • DisposableSubscriber

      public DisposableSubscriber()

  • Method Details

    • 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>

    • onStart

      protected void onStart()
      Called once the single upstream Subscription is set via onSubscribe(Subscription).

    • request

      protected final void request(long n)
      Requests the specified amount from the upstream if its Subscription is set via onSubscribe already.

      Note that calling this method before a Subscription is set via onSubscribe(Subscription) leads to NullPointerException and meant to be called from inside onStart() or Subscriber.onNext(Object).

      Parameters:
      n - the request amount, positive

    • cancel

      protected final void cancel()
      Cancels the Subscription set via onSubscribe(Subscription) or makes sure a Subscription set asynchronously (later) is cancelled immediately.

      This method is thread-safe and can be exposed as a public API.

    • isDisposed

      public final boolean isDisposed()
      Description copied from interface: Disposable
      Returns true if this resource has been disposed.
      Specified by:
      isDisposed in interface Disposable
      Returns:
      true if this resource has been disposed

    • dispose

      public final void dispose()
      Description copied from interface: Disposable
      Dispose the resource, the operation should be idempotent.
      Specified by:
      dispose in interface Disposable