/**
* Copyright (c) 2016-present, RxJava Contributors.
*
* 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 io.reactivex.internal.operators.observable;
import io.reactivex.internal.functions.
ObjectHelper;
import java.util.concurrent.
Callable;
import io.reactivex.*;
import io.reactivex.disposables.
Disposable;
import io.reactivex.exceptions.
Exceptions;
import io.reactivex.functions.
BiFunction;
import io.reactivex.internal.disposables.*;
import io.reactivex.plugins.
RxJavaPlugins;
public final class
ObservableScanSeed<T, R> extends
AbstractObservableWithUpstream<T, R> {
final
BiFunction<R, ? super T, R>
accumulator;
final
Callable<R>
seedSupplier;
public
ObservableScanSeed(
ObservableSource<T>
source,
Callable<R>
seedSupplier,
BiFunction<R, ? super T, R>
accumulator) {
super(
source);
this.
accumulator =
accumulator;
this.
seedSupplier =
seedSupplier;
}
@
Override
public void
subscribeActual(
Observer<? super R>
t) {
R
r;
try {
r =
ObjectHelper.
requireNonNull(
seedSupplier.
call(), "The seed supplied is null");
} catch (
Throwable e) {
Exceptions.
throwIfFatal(
e);
EmptyDisposable.
error(
e,
t);
return;
}
source.
subscribe(new
ScanSeedObserver<T, R>(
t,
accumulator,
r));
}
static final class
ScanSeedObserver<T, R> implements
Observer<T>,
Disposable {
final
Observer<? super R>
downstream;
final
BiFunction<R, ? super T, R>
accumulator;
R
value;
Disposable upstream;
boolean
done;
ScanSeedObserver(
Observer<? super R>
actual,
BiFunction<R, ? super T, R>
accumulator, R
value) {
this.
downstream =
actual;
this.
accumulator =
accumulator;
this.
value =
value;
}
@
Override
public void
onSubscribe(
Disposable d) {
if (
DisposableHelper.
validate(this.
upstream,
d)) {
this.
upstream =
d;
downstream.
onSubscribe(this);
downstream.
onNext(
value);
}
}
@
Override
public void
dispose() {
upstream.
dispose();
}
@
Override
public boolean
isDisposed() {
return
upstream.
isDisposed();
}
@
Override
public void
onNext(T
t) {
if (
done) {
return;
}
R
v =
value;
R
u;
try {
u =
ObjectHelper.
requireNonNull(
accumulator.
apply(
v,
t), "The accumulator returned a null value");
} catch (
Throwable e) {
Exceptions.
throwIfFatal(
e);
upstream.
dispose();
onError(
e);
return;
}
value =
u;
downstream.
onNext(
u);
}
@
Override
public void
onError(
Throwable t) {
if (
done) {
RxJavaPlugins.
onError(
t);
return;
}
done = true;
downstream.
onError(
t);
}
@
Override
public void
onComplete() {
if (
done) {
return;
}
done = true;
downstream.
onComplete();
}
}
}