Class ResourceObserver<T>
- java.lang.Object
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- io.reactivex.rxjava3.observers.ResourceObserver<T>
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- Type Parameters:
T
- the value type
- All Implemented Interfaces:
Observer<T>
,Disposable
public abstract class ResourceObserver<T> extends java.lang.Object implements Observer<T>, Disposable
An abstractObserver
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()
inonError()
andonComplete()
explicitly.Use
add(Disposable)
to associate resources (asDisposable
s) with thisResourceObserver
that will be cleaned up whendispose()
is called. Removing previously associated resources is not possible but one can create aCompositeDisposable
, associate it with thisResourceObserver
and then add/remove resources to/from theCompositeDisposable
freely.Use the
dispose()
to dispose the sequence from within anonNext
implementation.Like all other consumers,
ResourceObserver
can be subscribed only once. Any subsequent attempt to subscribe it to a new source will yield anIllegalStateException
with message"It is not allowed to subscribe with a(n) <class name> multiple times."
.Implementation of
onStart()
,Observer.onNext(Object)
,Observer.onError(Throwable)
andObserver.onComplete()
are not allowed to throw any unchecked exceptions. If for some reason this can't be avoided, useObservable.safeSubscribe(io.reactivex.rxjava3.core.Observer)
instead of the standardsubscribe()
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
Fields Modifier and Type Field Description private ListCompositeDisposable
resources
The resource composite, can never be null.private java.util.concurrent.atomic.AtomicReference<Disposable>
upstream
The active subscription.
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Constructor Summary
Constructors Constructor Description ResourceObserver()
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Method Summary
All Methods Instance Methods Concrete Methods Modifier and Type Method Description void
add(@NonNull Disposable resource)
Adds a resource to thisResourceObserver
.void
dispose()
Cancels the main disposable (if any) and disposes the resources associated with thisResourceObserver
(if any).boolean
isDisposed()
Returns true if thisResourceObserver
has been disposed/cancelled.protected void
onStart()
Called once the upstream sets aDisposable
on thisResourceObserver
.void
onSubscribe(Disposable d)
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
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Methods inherited from interface io.reactivex.rxjava3.core.Observer
onComplete, onError, onNext
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Field Detail
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upstream
private final java.util.concurrent.atomic.AtomicReference<Disposable> upstream
The active subscription.
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resources
private final ListCompositeDisposable resources
The resource composite, can never be null.
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Method Detail
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add
public final void add(@NonNull @NonNull Disposable resource)
Adds a resource to thisResourceObserver
.- Parameters:
resource
- the resource to add- Throws:
java.lang.NullPointerException
- if resource isnull
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onSubscribe
public final void onSubscribe(Disposable d)
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
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onStart
protected void onStart()
Called once the upstream sets aDisposable
on thisResourceObserver
.You can perform initialization at this moment. The default implementation does nothing.
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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
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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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