Package io.reactivex.rxjava3.observers

Class ResourceCompletableObserver

  • All Implemented Interfaces:
    CompletableObserver, Disposable
    public abstract class ResourceCompletableObserver
extends java.lang.Object
implements CompletableObserver, Disposable
    An abstract CompletableObserver that allows asynchronous cancellation of its subscription and associated resources.

    All pre-implemented final methods are thread-safe.

    Override the protected onStart() to perform initialization when this ResourceCompletableObserver is subscribed to a source.

    Use the public dispose() method to dispose the sequence externally and release all resources.

    To release the associated resources, one has to call dispose() in onError() and onComplete() explicitly.

    Use add(Disposable) to associate resources (as Disposables) with this ResourceCompletableObserver that will be cleaned up when dispose() is called. Removing previously associated resources is not possible but one can create a CompositeDisposable, associate it with this ResourceCompletableObserver and then add/remove resources to/from the CompositeDisposable freely.

    Like all other consumers, ResourceCompletableObserver 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(), CompletableObserver.onError(Throwable) and CompletableObserver.onComplete() are not allowed to throw any unchecked exceptions.

    Example

    
 Disposable d =
     Completable.complete().delay(1, TimeUnit.SECONDS)
     .subscribeWith(new ResourceCompletableObserver() {
         @Override public void onStart() {
             add(Schedulers.single()
                 .scheduleDirect(() -> System.out.println("Time!"),
                     2, TimeUnit.SECONDS));
         }
         @Override public void onError(Throwable t) {
             t.printStackTrace();
             dispose();
         }
         @Override public void onComplete() {
             System.out.println("Done!");
             dispose();
         }
     });
 // ...
 d.dispose();

    • Method Summary

      All Methods Instance Methods Concrete Methods 
      Modifier and Type Method Description
      void add​(@NonNull Disposable resource)
      Adds a resource to this ResourceCompletableObserver.
      void dispose()
      Cancels the main disposable (if any) and disposes the resources associated with this ResourceCompletableObserver (if any).
      boolean isDisposed()
      Returns true if this ResourceCompletableObserver has been disposed/cancelled.
      protected void onStart()
      Called once the upstream sets a Disposable on this ResourceCompletableObserver.
      void onSubscribe​(@NonNull Disposable d)
      Called once by the Completable to set a Disposable on this instance which then can be used to cancel the subscription at any time.

      • Methods inherited from class java.lang.Object

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

    • Field Detail

      • upstream

        private final java.util.concurrent.atomic.AtomicReference<Disposable> upstream
        The active subscription.

    • Constructor Detail

      • ResourceCompletableObserver

        public ResourceCompletableObserver()

    • Method Detail

      • add

        public final void add​(@NonNull
                      @NonNull Disposable resource)
        Adds a resource to this ResourceCompletableObserver.
        Parameters:
        resource - the resource to add
        Throws:
        java.lang.NullPointerException - if resource is null

      • onStart

        protected void onStart()
        Called once the upstream sets a Disposable on this ResourceCompletableObserver.

        You can perform initialization at this moment. The default implementation does nothing.

      • dispose

        public final void dispose()
        Cancels the main disposable (if any) and disposes the resources associated with this ResourceCompletableObserver (if any).

        This method can be called before the upstream calls onSubscribe(Disposable) at which case the main Disposable will be immediately disposed.

        Specified by:
        dispose in interface Disposable

      • isDisposed

        public final boolean isDisposed()
        Returns true if this ResourceCompletableObserver has been disposed/cancelled.
        Specified by:
        isDisposed in interface Disposable
        Returns:
        true if this ResourceCompletableObserver has been disposed/cancelled