Package io.reactivex.rxjava3.observers

Class TestObserver<T>

java.lang.Object

io.reactivex.rxjava3.observers.BaseTestConsumer<T,TestObserver<T>>

io.reactivex.rxjava3.observers.TestObserver<T>

Type Parameters:

T - the value type

All Implemented Interfaces:

CompletableObserver, MaybeObserver<T>, Observer<T>, SingleObserver<T>, Disposable

public class TestObserver<T>
extends BaseTestConsumer<T,TestObserver<T>>
implements Observer<T>, Disposable, MaybeObserver<T>, SingleObserver<T>, CompletableObserver

An Observer, MaybeObserver, SingleObserver and CompletableObserver composite that can record events from Observables, Maybes, Singles and Completables and allows making assertions about them.

You can override the onSubscribe(Disposable), onNext(Object), onError(Throwable), onComplete() and onSuccess(Object) methods but not the others (this is by design).

The TestObserver implements Disposable for convenience where dispose calls cancel.

See Also:

TestSubscriber

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
(package private) static class	TestObserver.EmptyObserver	An observer that ignores all events and does not report errors.

Field Summary

Fields

Modifier and Type	Field	Description
private Observer<? super T>	downstream	The actual observer to forward events to.
private java.util.concurrent.atomic.AtomicReference<Disposable>	upstream	Holds the current subscription if any.

Fields inherited from class io.reactivex.rxjava3.observers.BaseTestConsumer

checkSubscriptionOnce, completions, done, errors, lastThread, tag, timeout, values

Constructor Summary

Constructors

Constructor	Description
TestObserver()	Constructs a non-forwarding TestObserver.
TestObserver(@NonNull Observer<? super T> downstream)	Constructs a forwarding TestObserver.

Method Summary

Modifier and Type	Method	Description
protected @NonNull TestObserver<T>	assertSubscribed()	Assert that the onSubscribe(Disposable) method was called exactly once.
static <T> @NonNull TestObserver<T>	create()	Constructs a non-forwarding TestObserver.
static <T> @NonNull TestObserver<T>	create(@NonNull Observer<? super T> delegate)	Constructs a forwarding TestObserver.
void	dispose()	Cancel/dispose this test consumer.
boolean	hasSubscription()	Returns true if this TestObserver received a subscription.
boolean	isDisposed()	Returns true if this test consumer was cancelled/disposed.
void	onComplete()	Notifies the Observer that the Observable has finished sending push-based notifications.
void	onError(@NonNull java.lang.Throwable t)	Notifies the Observer that the Observable has experienced an error condition.
void	onNext(T t)	Provides the Observer with a new item to observe.
void	onSubscribe(@NonNull 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.
void	onSuccess(T value)	Notifies the MaybeObserver with one item and that the Maybe has finished sending push-based notifications.

Methods inherited from class io.reactivex.rxjava3.observers.BaseTestConsumer

assertComplete, assertEmpty, assertError, assertError, assertError, assertFailure, assertNoErrors, assertNotComplete, assertNoValues, assertResult, assertValue, assertValue, assertValueAt, assertValueAt, assertValueCount, assertValues, assertValueSequence, assertValuesOnly, await, await, awaitCount, awaitDone, fail, valueAndClass, values, withTag

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

downstream

private final Observer<? super T> downstream

The actual observer to forward events to.

upstream

private final java.util.concurrent.atomic.AtomicReference<Disposable> upstream

Holds the current subscription if any.

Constructor Detail

TestObserver

public TestObserver()

Constructs a non-forwarding TestObserver.

TestObserver

public TestObserver(@NonNull
                    @NonNull Observer<? super T> downstream)

Constructs a forwarding TestObserver.

Parameters:

downstream - the actual Observer to forward events to

Method Detail

create

@NonNull
public static <T> @NonNull TestObserver<T> create()

Constructs a non-forwarding TestObserver.

Type Parameters:

T - the value type received

Returns:

the new TestObserver instance

create

@NonNull
public static <T> @NonNull TestObserver<T> create(@NonNull
                                                  @NonNull Observer<? super T> delegate)

Constructs a forwarding TestObserver.

Type Parameters:

T - the value type received

Parameters:

delegate - the actual Observer to forward events to

Returns:

the new TestObserver instance

onSubscribe

public void onSubscribe(@NonNull
                        @NonNull Disposable d)

Description copied from interface: Observer

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.

Specified by:

onSubscribe in interface CompletableObserver

Specified by:

onSubscribe in interface MaybeObserver<T>

Specified by:

onSubscribe in interface Observer<T>

Specified by:

onSubscribe in interface SingleObserver<T>

Parameters:

d - the Disposable instance whose Disposable.dispose() can be called anytime to cancel the connection

onNext

public void onNext(@NonNull
                   T t)

Description copied from interface: Observer

Provides the Observer with a new item to observe.

The Observable may call this method 0 or more times.

The Observable will not call this method again after it calls either Observer.onComplete() or Observer.onError(java.lang.Throwable).

Specified by:

onNext in interface Observer<T>

Parameters:

t - the item emitted by the Observable

onError

public void onError(@NonNull
                    @NonNull java.lang.Throwable t)

Description copied from interface: Observer

Notifies the Observer that the Observable has experienced an error condition.

If the Observable calls this method, it will not thereafter call Observer.onNext(T) or Observer.onComplete().

Specified by:

onError in interface CompletableObserver

Specified by:

onError in interface MaybeObserver<T>

Specified by:

onError in interface Observer<T>

Specified by:

onError in interface SingleObserver<T>

Parameters:

t - the exception encountered by the Observable

onComplete

public void onComplete()

Description copied from interface: Observer

Notifies the Observer that the Observable has finished sending push-based notifications.

The Observable will not call this method if it calls Observer.onError(java.lang.Throwable).

Specified by:

onComplete in interface CompletableObserver

Specified by:

onComplete in interface MaybeObserver<T>

Specified by:

onComplete in interface Observer<T>

dispose

public final void dispose()

Description copied from class: BaseTestConsumer

Cancel/dispose this test consumer.

Specified by:

dispose in interface Disposable

Specified by:

dispose in class BaseTestConsumer<T,TestObserver<T>>

isDisposed

public final boolean isDisposed()

Description copied from class: BaseTestConsumer

Returns true if this test consumer was cancelled/disposed.

Specified by:

isDisposed in interface Disposable

Specified by:

isDisposed in class BaseTestConsumer<T,TestObserver<T>>

Returns:

true if this test consumer was cancelled/disposed.

hasSubscription

public final boolean hasSubscription()

Returns true if this TestObserver received a subscription.

Returns:

true if this TestObserver received a subscription

assertSubscribed

@NonNull
protected final @NonNull TestObserver<T> assertSubscribed()

Assert that the onSubscribe(Disposable) method was called exactly once.

Specified by:

assertSubscribed in class BaseTestConsumer<T,TestObserver<T>>

Returns:

this

onSuccess

public void onSuccess(@NonNull
                      T value)

Description copied from interface: MaybeObserver

Notifies the MaybeObserver with one item and that the Maybe has finished sending push-based notifications.

The Maybe will not call this method if it calls MaybeObserver.onError(java.lang.Throwable).

Specified by:

onSuccess in interface MaybeObserver<T>

Specified by:

onSuccess in interface SingleObserver<T>

Parameters:

value - the item emitted by the Maybe