RxJava

rx.operators
Class SafeObserver<T>

java.lang.Object
  rx.operators.SafeObserver<T>

Type Parameters:

T -

All Implemented Interfaces:

Observer<T>

public class SafeObserver<T>
extends java.lang.Object
implements Observer<T>

Wrapper around Observer to ensure compliance with Rx contract.

The following is taken from the Rx Design Guidelines document: http://go.microsoft.com/fwlink/?LinkID=205219

 Messages sent to instances of the IObserver interface follow the following grammar:
 
 OnNext* (OnCompleted | OnError)?
 
 This grammar allows observable sequences to send any amount (0 or more) of OnNext messages to the subscribed
 observer instance, optionally followed by a single success (OnCompleted) or failure (OnError) message.
 
 The single message indicating that an observable sequence has finished ensures that consumers of the observable
 sequence can deterministically establish that it is safe to perform cleanup operations.
 
 A single failure further ensures that abort semantics can be maintained for operators that work on
 multiple observable sequences (see paragraph 6.6).
 

This wrapper will do the following:

• Allow only single execution of either onError or onCompleted.
• Once an onComplete or onError are performed, no further calls can be executed
• If unsubscribe is called, this means we call completed() and don't allow any further onNext calls.
• When onError or onComplete occur it will unsubscribe from the Observable (if executing asynchronously).

It will not synchronize onNext execution. Use the SynchronizedObserver to do that.

Constructor Summary

SafeObserver(SafeObservableSubscription subscription, Observer<? super T> actual)

Method Summary

void	onCompleted() Notifies the Observer that the Observable has finished sending push-based notifications.
void	onError(java.lang.Throwable e) Notifies the Observer that the Observable has experienced an error condition.
void	onNext(T args) Provides the Observer with new data.

Methods inherited from class java.lang.Object

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

Constructor Detail

SafeObserver

public SafeObserver(SafeObservableSubscription subscription,
                    Observer<? super T> actual)

Method Detail

onCompleted

public void onCompleted()

Description copied from interface: Observer

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

The Observable will not call this closure if it calls onError.

Specified by:

onCompleted in interface Observer<T>

onError

public void onError(java.lang.Throwable e)

Description copied from interface: Observer

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

If the Observable calls this closure, it will not thereafter call onNext or onCompleted.

Specified by:

onError in interface Observer<T>

onNext

public void onNext(T args)

Description copied from interface: Observer

Provides the Observer with new data.

The Observable calls this closure 1 or more times, unless it calls onError in which case this closure may never be called.

The Observable will not call this closure again after it calls either onCompleted or onError.

Specified by:

onNext in interface Observer<T>