/**
* 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.flowable;
import java.util.
NoSuchElementException;
import org.reactivestreams.
Subscription;
import io.reactivex.*;
import io.reactivex.disposables.
Disposable;
import io.reactivex.internal.fuseable.
FuseToFlowable;
import io.reactivex.internal.subscriptions.
SubscriptionHelper;
import io.reactivex.plugins.
RxJavaPlugins;
public final class
FlowableSingleSingle<T> extends
Single<T> implements
FuseToFlowable<T> {
final
Flowable<T>
source;
final T
defaultValue;
public
FlowableSingleSingle(
Flowable<T>
source, T
defaultValue) {
this.
source =
source;
this.
defaultValue =
defaultValue;
}
@
Override
protected void
subscribeActual(
SingleObserver<? super T>
observer) {
source.
subscribe(new
SingleElementSubscriber<T>(
observer,
defaultValue));
}
@
Override
public
Flowable<T>
fuseToFlowable() {
return
RxJavaPlugins.
onAssembly(new
FlowableSingle<T>(
source,
defaultValue, true));
}
static final class
SingleElementSubscriber<T>
implements
FlowableSubscriber<T>,
Disposable {
final
SingleObserver<? super T>
downstream;
final T
defaultValue;
Subscription upstream;
boolean
done;
T
value;
SingleElementSubscriber(
SingleObserver<? super T>
actual, T
defaultValue) {
this.
downstream =
actual;
this.
defaultValue =
defaultValue;
}
@
Override
public void
onSubscribe(
Subscription s) {
if (
SubscriptionHelper.
validate(this.
upstream,
s)) {
this.
upstream =
s;
downstream.
onSubscribe(this);
s.
request(
Long.
MAX_VALUE);
}
}
@
Override
public void
onNext(T
t) {
if (
done) {
return;
}
if (
value != null) {
done = true;
upstream.
cancel();
upstream =
SubscriptionHelper.
CANCELLED;
downstream.
onError(new
IllegalArgumentException("Sequence contains more than one element!"));
return;
}
value =
t;
}
@
Override
public void
onError(
Throwable t) {
if (
done) {
RxJavaPlugins.
onError(
t);
return;
}
done = true;
upstream =
SubscriptionHelper.
CANCELLED;
downstream.
onError(
t);
}
@
Override
public void
onComplete() {
if (
done) {
return;
}
done = true;
upstream =
SubscriptionHelper.
CANCELLED;
T
v =
value;
value = null;
if (
v == null) {
v =
defaultValue;
}
if (
v != null) {
downstream.
onSuccess(
v);
} else {
downstream.
onError(new
NoSuchElementException());
}
}
@
Override
public void
dispose() {
upstream.
cancel();
upstream =
SubscriptionHelper.
CANCELLED;
}
@
Override
public boolean
isDisposed() {
return
upstream ==
SubscriptionHelper.
CANCELLED;
}
}
}