rx.internal.operators.OperatorOnErrorResumeNextViaFunction Maven / Gradle / Ivy
/**
* Copyright 2014 Netflix, Inc.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package rx.internal.operators;
import rx.*;
import rx.Observable.Operator;
import rx.exceptions.Exceptions;
import rx.functions.Func1;
import rx.internal.producers.ProducerArbiter;
import rx.plugins.RxJavaHooks;
import rx.subscriptions.SerialSubscription;
/**
* Instruct an Observable to pass control to another Observable (the return value of a function)
* rather than invoking {@code onError} if it encounters an error.
*
* 
*
* By default, when an Observable encounters an error that prevents it from emitting the expected item to its
* Observer, the Observable invokes its Observer's {@code onError} method, and then quits without invoking any
* more of its Observer's methods. The {@code onErrorResumeNext} operation changes this behavior. If you pass a
* function that returns an Observable ({@code resumeFunction}) to {@code onErrorResumeNext}, if the source
* Observable encounters an error, instead of invoking its Observer's {@code onError} method, it will instead
* relinquish control to this new Observable, which will invoke the Observer's {@code onNext} method if it is
* able to do so. In such a case, because no Observable necessarily invokes {@code onError}, the Observer may
* never know that an error happened.
*
* You can use this to prevent errors from propagating or to supply fallback data should errors be
* encountered.
* @param the value type
*/
public final class OperatorOnErrorResumeNextViaFunction implements Operator {
final Func1> resumeFunction;
public static OperatorOnErrorResumeNextViaFunction withSingle(final Func1 resumeFunction) {
return new OperatorOnErrorResumeNextViaFunction(new Func1>() {
@Override
public Observable call(Throwable t) {
return Observable.just(resumeFunction.call(t));
}
});
}
public static OperatorOnErrorResumeNextViaFunction withOther(final Observable other) {
return new OperatorOnErrorResumeNextViaFunction(new Func1>() {
@Override
public Observable call(Throwable t) {
return other;
}
});
}
public static OperatorOnErrorResumeNextViaFunction withException(final Observable other) {
return new OperatorOnErrorResumeNextViaFunction(new Func1>() {
@Override
public Observable call(Throwable t) {
if (t instanceof Exception) {
return other;
}
return Observable.error(t);
}
});
}
public OperatorOnErrorResumeNextViaFunction(Func1> f) {
this.resumeFunction = f;
}
@Override
public Subscriber call(final Subscriber child) {
final ProducerArbiter pa = new ProducerArbiter();
final SerialSubscription serial = new SerialSubscription();
Subscriber parent = new Subscriber() {
private boolean done;
long produced;
@Override
public void onCompleted() {
if (done) {
return;
}
done = true;
child.onCompleted();
}
@Override
public void onError(Throwable e) {
if (done) {
Exceptions.throwIfFatal(e);
RxJavaHooks.onError(e);
return;
}
done = true;
try {
unsubscribe();
Subscriber next = new Subscriber() {
@Override
public void onNext(T t) {
child.onNext(t);
}
@Override
public void onError(Throwable e) {
child.onError(e);
}
@Override
public void onCompleted() {
child.onCompleted();
}
@Override
public void setProducer(Producer producer) {
pa.setProducer(producer);
}
};
serial.set(next);
long p = produced;
if (p != 0L) {
pa.produced(p);
}
Observable resume = resumeFunction.call(e);
resume.unsafeSubscribe(next);
} catch (Throwable e2) {
Exceptions.throwOrReport(e2, child);
}
}
@Override
public void onNext(T t) {
if (done) {
return;
}
produced++;
child.onNext(t);
}
@Override
public void setProducer(final Producer producer) {
pa.setProducer(producer);
}
};
serial.set(parent);
child.add(serial);
child.setProducer(pa);
return parent;
}
}