rx.internal.operators.OnSubscribeReduce Maven / Gradle / Ivy
/**
* Copyright 2016 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 java.util.NoSuchElementException;
import rx.*;
import rx.Observable.OnSubscribe;
import rx.exceptions.Exceptions;
import rx.functions.Func2;
import rx.plugins.RxJavaHooks;
public final class OnSubscribeReduce implements OnSubscribe {
final Observable source;
final Func2 reducer;
public OnSubscribeReduce(Observable source, Func2 reducer) {
this.source = source;
this.reducer = reducer;
}
@Override
public void call(Subscriber super T> t) {
final ReduceSubscriber parent = new ReduceSubscriber(t, reducer);
t.add(parent);
t.setProducer(new Producer() {
@Override
public void request(long n) {
parent.downstreamRequest(n);
}
});
source.unsafeSubscribe(parent);
}
static final class ReduceSubscriber extends Subscriber {
final Subscriber super T> actual;
final Func2 reducer;
T value;
static final Object EMPTY = new Object();
boolean done;
@SuppressWarnings("unchecked")
public ReduceSubscriber(Subscriber super T> actual, Func2 reducer) {
this.actual = actual;
this.reducer = reducer;
this.value = (T)EMPTY;
this.request(0);
}
@SuppressWarnings("unchecked")
@Override
public void onNext(T t) {
if (done) {
return;
}
Object o = value;
if (o == EMPTY) {
value = t;
} else {
try {
value = reducer.call((T)o, t);
} catch (Throwable ex) {
Exceptions.throwIfFatal(ex);
unsubscribe();
onError(ex);
}
}
}
@Override
public void onError(Throwable e) {
if (!done) {
done = true;
actual.onError(e);
} else {
RxJavaHooks.onError(e);
}
}
@SuppressWarnings("unchecked")
@Override
public void onCompleted() {
if (done) {
return;
}
done = true;
Object o = value;
if (o != EMPTY) {
actual.onNext((T)o);
actual.onCompleted();
} else {
actual.onError(new NoSuchElementException());
}
}
void downstreamRequest(long n) {
if (n < 0L) {
throw new IllegalArgumentException("n >= 0 required but it was " + n);
}
if (n != 0L) {
request(Long.MAX_VALUE);
}
}
}
}
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