Package io.reactivex.rxjava3.internal.observers

Class BasicFuseableObserver<T,R>

java.lang.Object

io.reactivex.rxjava3.internal.observers.BasicFuseableObserver<T,R>

Type Parameters:

T - the upstream value type

R - the downstream value type

All Implemented Interfaces:

Observer<T>, Disposable, QueueDisposable<R>, QueueFuseable<R>, SimpleQueue<R>

Direct Known Subclasses:

ObservableDistinct.DistinctObserver, ObservableDistinctUntilChanged.DistinctUntilChangedObserver, ObservableDoAfterNext.DoAfterObserver, ObservableFilter.FilterObserver, ObservableMap.MapObserver, ObservableMapOptional.MapOptionalObserver

public abstract class BasicFuseableObserver<T,R>
extends java.lang.Object
implements Observer<T>, QueueDisposable<R>

Base class for a fuseable intermediate observer.

Field Summary

Fields

Modifier and Type	Field	Description
protected boolean	done	Flag indicating no further onXXX event should be accepted.
protected Observer<? super R>	downstream	The downstream subscriber.
protected QueueDisposable<T>	qd	The upstream's QueueDisposable if not null.
protected int	sourceMode	Holds the established fusion mode of the upstream.
protected Disposable	upstream	The upstream subscription.

Fields inherited from interface io.reactivex.rxjava3.operators.QueueFuseable

ANY, ASYNC, BOUNDARY, NONE, SYNC

Constructor Summary

Constructors

Constructor	Description
BasicFuseableObserver(Observer<? super R> downstream)	Construct a BasicFuseableObserver by wrapping the given subscriber.

Method Summary

Modifier and Type	Method	Description
protected void	afterDownstream()	Override this to perform actions after the call to actual.onSubscribe(this) happened.
protected boolean	beforeDownstream()	Override this to perform actions before the call actual.onSubscribe(this) happens.
void	clear()	Removes all enqueued items from this queue.
void	dispose()	Dispose the resource, the operation should be idempotent.
protected void	fail(java.lang.Throwable t)	Rethrows the throwable if it is a fatal exception or calls onError(Throwable).
boolean	isDisposed()	Returns true if this resource has been disposed.
boolean	isEmpty()	Returns true if the queue is empty.
boolean	offer(R e)	Atomically enqueue a single value.
boolean	offer(R v1, R v2)	Atomically enqueue two values.
void	onComplete()	Notifies the Observer that the Observable has finished sending push-based notifications.
void	onError(java.lang.Throwable t)	Notifies the Observer that the Observable has experienced an error condition.
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.
protected int	transitiveBoundaryFusion(int mode)	Calls the upstream's QueueDisposable.requestFusion with the mode and saves the established mode in sourceMode if that mode doesn't have the QueueFuseable.BOUNDARY flag set.

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

onNext

Methods inherited from interface io.reactivex.rxjava3.operators.QueueFuseable

requestFusion

Methods inherited from interface io.reactivex.rxjava3.operators.SimpleQueue

poll

Field Detail

downstream

protected final Observer<? super R> downstream

The downstream subscriber.

upstream

protected Disposable upstream

The upstream subscription.

qd

protected QueueDisposable<T> qd

The upstream's QueueDisposable if not null.

done

protected boolean done

Flag indicating no further onXXX event should be accepted.

sourceMode

protected int sourceMode

Holds the established fusion mode of the upstream.

Constructor Detail

BasicFuseableObserver

public BasicFuseableObserver(Observer<? super R> downstream)

Construct a BasicFuseableObserver by wrapping the given subscriber.

Parameters:

downstream - the subscriber, not null (not verified)

Method Detail

onSubscribe

public final void onSubscribe(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 Observer<T>

Parameters:

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

beforeDownstream

protected boolean beforeDownstream()

Override this to perform actions before the call actual.onSubscribe(this) happens.

Returns:

true if onSubscribe should continue with the call

afterDownstream

protected void afterDownstream()

Override this to perform actions after the call to actual.onSubscribe(this) happened.

onError

public void onError(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 Observer<T>

Parameters:

t - the exception encountered by the Observable

fail

protected final void fail(java.lang.Throwable t)

Rethrows the throwable if it is a fatal exception or calls onError(Throwable).

Parameters:

t - the throwable to rethrow or signal to the actual subscriber

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 Observer<T>

transitiveBoundaryFusion

protected final int transitiveBoundaryFusion(int mode)

Calls the upstream's QueueDisposable.requestFusion with the mode and saves the established mode in sourceMode if that mode doesn't have the QueueFuseable.BOUNDARY flag set.

If the upstream doesn't support fusion (qd is null), the method returns QueueFuseable.NONE.

Parameters:

mode - the fusion mode requested

Returns:

the established fusion mode

dispose

public void dispose()

Description copied from interface: Disposable

Dispose the resource, the operation should be idempotent.

Specified by:

dispose in interface Disposable

isDisposed

public boolean isDisposed()

Description copied from interface: Disposable

Returns true if this resource has been disposed.

Specified by:

isDisposed in interface Disposable

Returns:

true if this resource has been disposed

isEmpty

public boolean isEmpty()

Description copied from interface: SimpleQueue

Returns true if the queue is empty.

Note however that due to potential fused functions in SimpleQueue.poll() it is possible this method returns false but then poll() returns null because the fused function swallowed the available item(s).

Specified by:

isEmpty in interface SimpleQueue<T>

Returns:

true if the queue is empty

clear

public void clear()

Description copied from interface: SimpleQueue

Removes all enqueued items from this queue.

Specified by:

clear in interface SimpleQueue<T>

offer

public final boolean offer(R e)

Description copied from interface: SimpleQueue

Atomically enqueue a single value.

Specified by:

offer in interface SimpleQueue<T>

Parameters:

e - the value to enqueue, not null

Returns:

true if successful, false if the value was not enqueued likely due to reaching the queue capacity)

offer

public final boolean offer(R v1,
                           R v2)

Description copied from interface: SimpleQueue

Atomically enqueue two values.

Specified by:

offer in interface SimpleQueue<T>

Parameters:

v1 - the first value to enqueue, not null

v2 - the second value to enqueue, not null

Returns:

true if successful, false if the value was not enqueued likely due to reaching the queue capacity)