T
- the value typepublic abstract class DefaultObserver<T> extends Object implements Observer<T>
Observer
with support for cancelling a
subscription via cancel()
(synchronously) and calls onStart()
when the subscription happens.
All pre-implemented final methods are thread-safe.
Use the protected cancel()
to dispose the sequence from within an
onNext
implementation.
Like all other consumers, DefaultObserver
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.Observer)
instead of the standard subscribe()
method.
Example
Observable.range(1, 5)
.subscribe(new DefaultObserver<Integer>() {
@Override public void onStart() {
System.out.println("Start!");
}
@Override public void onNext(Integer t) {
if (t == 3) {
cancel();
}
System.out.println(t);
}
@Override public void onError(Throwable t) {
t.printStackTrace();
}
@Override public void onComplete() {
System.out.println("Done!");
}
});
Constructor and Description |
---|
DefaultObserver() |
Modifier and Type | Method and Description |
---|---|
protected void |
cancel()
Cancels the upstream's disposable.
|
protected void |
onStart()
Called once the subscription has been set on this observer; override this
to perform initialization.
|
void |
onSubscribe(Disposable d)
Provides the Observer with the means of cancelling (disposing) the
connection (channel) with the Observable in both
synchronous (from within
Observer.onNext(Object) ) and asynchronous manner. |
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
onComplete, onError, onNext
public final void onSubscribe(@NonNull Disposable d)
Observer
Observer.onNext(Object)
) and asynchronous manner.onSubscribe
in interface Observer<T>
d
- the Disposable instance whose Disposable.dispose()
can
be called anytime to cancel the connectionprotected final void cancel()
protected void onStart()