Class ResourceCompletableObserver

java.lang.Object
io.reactivex.rxjava4.observers.ResourceCompletableObserver
All Implemented Interfaces:
CompletableObserver, Disposable
public abstract class ResourceCompletableObserver extends 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();

  • Constructor Details

    • ResourceCompletableObserver

      public ResourceCompletableObserver()

  • Method Details

    • add

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

    • onSubscribe

      public final void onSubscribe(@NonNull @NonNull Disposable d)
      Description copied from interface: CompletableObserver
      Called once by the Completable to set a Disposable on this instance which then can be used to cancel the subscription at any time.
      Specified by:
      onSubscribe in interface CompletableObserver
      Parameters:
      d - the Disposable instance to call dispose on for cancellation, not 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