Class ResourceObserver<T>
- Type Parameters:
T
- the value type
- All Implemented Interfaces:
Observer<T>
,Disposable
Observer
that allows asynchronous cancellation of its subscription and associated resources.
All pre-implemented final methods are thread-safe.
To release the associated resources, one has to call dispose()
in onError()
and onComplete()
explicitly.
Use add(Disposable)
to associate resources (as Disposable
s)
with this ResourceObserver
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
ResourceObserver
and then add/remove resources to/from the CompositeDisposable
freely.
Use the dispose()
to dispose the sequence from within an
onNext
implementation.
Like all other consumers, ResourceObserver
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()
, Observer.onNext(Object)
, Observer.onError(Throwable)
and Observer.onComplete()
are not allowed to throw any unchecked exceptions.
If for some reason this can't be avoided, use Observable.safeSubscribe(io.reactivex.rxjava3.core.Observer)
instead of the standard subscribe()
method.
Example
Disposable d =
Observable.range(1, 5)
.subscribeWith(new ResourceObserver<Integer>() {
@Override public void onStart() {
add(Schedulers.single()
.scheduleDirect(() -> System.out.println("Time!"),
2, TimeUnit.SECONDS));
request(1);
}
@Override public void onNext(Integer t) {
if (t == 3) {
dispose();
}
System.out.println(t);
}
@Override public void onError(Throwable t) {
t.printStackTrace();
dispose();
}
@Override public void onComplete() {
System.out.println("Done!");
dispose();
}
});
// ...
d.dispose();
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Field Summary
FieldsModifier and TypeFieldDescriptionprivate final ListCompositeDisposable
The resource composite, can never be null.private final AtomicReference
<Disposable> The active subscription. -
Constructor Summary
Constructors -
Method Summary
Modifier and TypeMethodDescriptionfinal void
add
(@NonNull Disposable resource) Adds a resource to thisResourceObserver
.final void
dispose()
Cancels the main disposable (if any) and disposes the resources associated with thisResourceObserver
(if any).final boolean
Returns true if thisResourceObserver
has been disposed/cancelled.protected void
onStart()
Called once the upstream sets aDisposable
on thisResourceObserver
.final void
Provides theObserver
with the means of cancelling (disposing) the connection (channel) with theObservable
in both synchronous (from withinObserver.onNext(Object)
) and asynchronous manner.Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
Methods inherited from interface io.reactivex.rxjava3.core.Observer
onComplete, onError, onNext
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Field Details
-
upstream
The active subscription. -
resources
The resource composite, can never be null.
-
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Constructor Details
-
ResourceObserver
public ResourceObserver()
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Method Details
-
add
Adds a resource to thisResourceObserver
.- Parameters:
resource
- the resource to add- Throws:
NullPointerException
- if resource isnull
-
onSubscribe
Description copied from interface:Observer
Provides theObserver
with the means of cancelling (disposing) the connection (channel) with theObservable
in both synchronous (from withinObserver.onNext(Object)
) and asynchronous manner.- Specified by:
onSubscribe
in interfaceObserver<T>
- Parameters:
d
- theDisposable
instance whoseDisposable.dispose()
can be called anytime to cancel the connection
-
onStart
protected void onStart()Called once the upstream sets aDisposable
on thisResourceObserver
.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 thisResourceObserver
(if any).This method can be called before the upstream calls
onSubscribe(Disposable)
at which case the mainDisposable
will be immediately disposed.- Specified by:
dispose
in interfaceDisposable
-
isDisposed
public final boolean isDisposed()Returns true if thisResourceObserver
has been disposed/cancelled.- Specified by:
isDisposed
in interfaceDisposable
- Returns:
- true if this
ResourceObserver
has been disposed/cancelled
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