/**
* 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.maybe;
import java.util.
NoSuchElementException;
import io.reactivex.*;
import io.reactivex.disposables.
Disposable;
import io.reactivex.internal.disposables.
DisposableHelper;
import io.reactivex.internal.fuseable.
HasUpstreamMaybeSource;
/**
* Wraps a MaybeSource and exposes its onSuccess and onError signals and signals
* NoSuchElementException for onComplete.
*
* @param <T> the value type
*/
public final class
MaybeToSingle<T> extends
Single<T> implements
HasUpstreamMaybeSource<T> {
final
MaybeSource<T>
source;
final T
defaultValue;
public
MaybeToSingle(
MaybeSource<T>
source, T
defaultValue) {
this.
source =
source;
this.
defaultValue =
defaultValue;
}
@
Override
public
MaybeSource<T>
source() {
return
source;
}
@
Override
protected void
subscribeActual(
SingleObserver<? super T>
observer) {
source.
subscribe(new
ToSingleMaybeSubscriber<T>(
observer,
defaultValue));
}
static final class
ToSingleMaybeSubscriber<T> implements
MaybeObserver<T>,
Disposable {
final
SingleObserver<? super T>
downstream;
final T
defaultValue;
Disposable upstream;
ToSingleMaybeSubscriber(
SingleObserver<? super T>
actual, T
defaultValue) {
this.
downstream =
actual;
this.
defaultValue =
defaultValue;
}
@
Override
public void
dispose() {
upstream.
dispose();
upstream =
DisposableHelper.
DISPOSED;
}
@
Override
public boolean
isDisposed() {
return
upstream.
isDisposed();
}
@
Override
public void
onSubscribe(
Disposable d) {
if (
DisposableHelper.
validate(this.
upstream,
d)) {
this.
upstream =
d;
downstream.
onSubscribe(this);
}
}
@
Override
public void
onSuccess(T
value) {
upstream =
DisposableHelper.
DISPOSED;
downstream.
onSuccess(
value);
}
@
Override
public void
onError(
Throwable e) {
upstream =
DisposableHelper.
DISPOSED;
downstream.
onError(
e);
}
@
Override
public void
onComplete() {
upstream =
DisposableHelper.
DISPOSED;
if (
defaultValue != null) {
downstream.
onSuccess(
defaultValue);
} else {
downstream.
onError(new
NoSuchElementException("The MaybeSource is empty"));
}
}
}
}