DefaultObserver

Class Overview

Abstract base implementation of an 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(), onNext(Object), onError(Throwable) and onComplete() are not allowed to throw any unchecked exceptions. If for some reason this can't be avoided, use 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!");
         }
     });
 

Summary

[Expand] Inherited Methods
From class java.lang.Object Object clone() boolean equals(Object arg0) void finalize() final Class<?> getClass() int hashCode() final void notify() final void notifyAll() String toString() final void wait(long arg0, int arg1) final void wait(long arg0) final void wait()
From interface io.reactivex.Observer abstract void onComplete() Notifies the Observer that the Observable has finished sending push-based notifications. abstract void onError(Throwable e) Notifies the Observer that the Observable has experienced an error condition. abstract void onNext(T t) Provides the Observer with a new item to observe. abstract void onSubscribe(Disposable d) Provides the Observer with the means of cancelling (disposing) the connection (channel) with the Observable in both synchronous (from within onNext(Object)) and asynchronous manner.