Package io.reactivex.rxjava3.observers

Class ResourceSingleObserver<T>

  • Type Parameters:
    T - the value type
    All Implemented Interfaces:
    SingleObserver<T>, Disposable
    public abstract class ResourceSingleObserver<T>
extends java.lang.Object
implements SingleObserver<T>, Disposable
    An abstract SingleObserver that allows asynchronous cancellation of its subscription and the associated resources.

    All pre-implemented final methods are thread-safe.

    Override the protected onStart() to perform initialization when this ResourceSingleObserver 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 onSuccess() and onError() explicitly.

    Use add(Disposable) to associate resources (as Disposables) with this ResourceSingleObserver 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 ResourceSingleObserver and then add/remove resources to/from the CompositeDisposable freely.

    Like all other consumers, ResourceSingleObserver 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(), SingleObserver.onSuccess(Object) and SingleObserver.onError(Throwable) are not allowed to throw any unchecked exceptions.

    Example

    
 Disposable d =
     Single.just(1).delay(1, TimeUnit.SECONDS)
     .subscribeWith(new ResourceSingleObserver<Integer>() {
         @Override public void onStart() {
             add(Schedulers.single()
                 .scheduleDirect(() -> System.out.println("Time!"),
                     2, TimeUnit.SECONDS));
         }
         @Override public void onSuccess(Integer t) {
             System.out.println(t);
             dispose();
         }
         @Override public void onError(Throwable t) {
             t.printStackTrace();
             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 ResourceSingleObserver.
      void dispose()
      Cancels the main disposable (if any) and disposes the resources associated with this ResourceSingleObserver (if any).
      boolean isDisposed()
      Returns true if this ResourceSingleObserver has been disposed/cancelled.
      protected void onStart()
      Called once the upstream sets a Disposable on this ResourceSingleObserver.
      void onSubscribe​(@NonNull Disposable d)
      Provides the SingleObserver with the means of cancelling (disposing) the connection (channel) with the Single in both synchronous (from within onSubscribe(Disposable) itself) and asynchronous manner.

      • 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

      • ResourceSingleObserver

        public ResourceSingleObserver()

    • Method Detail

      • add

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

      • onSubscribe

        public final void onSubscribe​(@NonNull
                              @NonNull Disposable d)
        Description copied from interface: SingleObserver
        Provides the SingleObserver with the means of cancelling (disposing) the connection (channel) with the Single in both synchronous (from within onSubscribe(Disposable) itself) and asynchronous manner.
        Specified by:
        onSubscribe in interface SingleObserver<T>
        Parameters:
        d - the Disposable instance whose Disposable.dispose() can be called anytime to cancel the connection

      • onStart

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

        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 ResourceSingleObserver (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 ResourceSingleObserver has been disposed/cancelled.
        Specified by:
        isDisposed in interface Disposable
        Returns:
        true if this ResourceSingleObserver has been disposed/cancelled