T - the value typepublic abstract class ResourceSubscriber<T> extends java.lang.Object implements FlowableSubscriber<T>, Disposable
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 Disposables)
with this ResourceSubscriber 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
ResourceSubscriber and then add/remove resources to/from the CompositeDisposable
freely.
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 dispose() 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, ResourceSubscriber can be subscribed only once.
Any subsequent attempt to subscribe it to a new source will yield an
IllegalStateException with message "Subscription already set!".
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 ResourceSubscriber<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);
request(1);
}
@Override public void onError(Throwable t) {
t.printStackTrace();
dispose();
}
@Override public void onComplete() {
System.out.println("Done!");
dispose();
}
});
// ...
d.dispose();
| Constructor and Description |
|---|
ResourceSubscriber() |
| Modifier and Type | Method and Description |
|---|---|
void |
add(Disposable resource)
Adds a resource to this AsyncObserver.
|
void |
dispose()
Cancels the subscription (if any) and disposes the resources associated with
this AsyncObserver (if any).
|
boolean |
isDisposed()
Returns true if this AsyncObserver has been disposed/cancelled.
|
protected void |
onStart()
Called once the upstream sets a Subscription on this AsyncObserver.
|
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 void |
request(long n)
Request the specified amount of elements from upstream.
|
public final void add(Disposable resource)
resource - the resource to addjava.lang.NullPointerException - if resource is nullpublic final void onSubscribe(org.reactivestreams.Subscription s)
FlowableSubscriberSubscriber.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.
onSubscribe in interface FlowableSubscriber<T>onSubscribe in interface org.reactivestreams.Subscriber<T>protected void onStart()
You can perform initialization at this moment. The default implementation requests Long.MAX_VALUE from upstream.
protected final void request(long n)
This method can be called before the upstream calls onSubscribe(). When the subscription happens, all missed requests are requested.
n - the request amount, must be positivepublic final void dispose()
This method can be called before the upstream calls onSubscribe at which case the Subscription will be immediately cancelled.
dispose in interface Disposablepublic final boolean isDisposed()
isDisposed in interface Disposable