/**
* 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.concurrent.atomic.
AtomicReference;
import io.reactivex.*;
import io.reactivex.disposables.
Disposable;
import io.reactivex.exceptions.
Exceptions;
import io.reactivex.functions.
Function;
import io.reactivex.internal.disposables.
DisposableHelper;
import io.reactivex.internal.functions.
ObjectHelper;
/**
* Maps the success value of the source MaybeSource into a Single.
* <p>History: 2.0.2 - experimental
* @param <T> the input value type
* @param <R> the result value type
* @since 2.1
*/
public final class
MaybeFlatMapSingleElement<T, R> extends
Maybe<R> {
final
MaybeSource<T>
source;
final
Function<? super T, ? extends
SingleSource<? extends R>>
mapper;
public
MaybeFlatMapSingleElement(
MaybeSource<T>
source,
Function<? super T, ? extends
SingleSource<? extends R>>
mapper) {
this.
source =
source;
this.
mapper =
mapper;
}
@
Override
protected void
subscribeActual(
MaybeObserver<? super R>
downstream) {
source.
subscribe(new
FlatMapMaybeObserver<T, R>(
downstream,
mapper));
}
static final class
FlatMapMaybeObserver<T, R>
extends
AtomicReference<
Disposable>
implements
MaybeObserver<T>,
Disposable {
private static final long
serialVersionUID = 4827726964688405508L;
final
MaybeObserver<? super R>
downstream;
final
Function<? super T, ? extends
SingleSource<? extends R>>
mapper;
FlatMapMaybeObserver(
MaybeObserver<? super R>
actual,
Function<? super T, ? extends
SingleSource<? extends R>>
mapper) {
this.
downstream =
actual;
this.
mapper =
mapper;
}
@
Override
public void
dispose() {
DisposableHelper.
dispose(this);
}
@
Override
public boolean
isDisposed() {
return
DisposableHelper.
isDisposed(
get());
}
@
Override
public void
onSubscribe(
Disposable d) {
if (
DisposableHelper.
setOnce(this,
d)) {
downstream.
onSubscribe(this);
}
}
@
Override
public void
onSuccess(T
value) {
SingleSource<? extends R>
ss;
try {
ss =
ObjectHelper.
requireNonNull(
mapper.
apply(
value), "The mapper returned a null SingleSource");
} catch (
Throwable ex) {
Exceptions.
throwIfFatal(
ex);
onError(
ex);
return;
}
ss.
subscribe(new
FlatMapSingleObserver<R>(this,
downstream));
}
@
Override
public void
onError(
Throwable e) {
downstream.
onError(
e);
}
@
Override
public void
onComplete() {
downstream.
onComplete();
}
}
static final class
FlatMapSingleObserver<R> implements
SingleObserver<R> {
final
AtomicReference<
Disposable>
parent;
final
MaybeObserver<? super R>
downstream;
FlatMapSingleObserver(
AtomicReference<
Disposable>
parent,
MaybeObserver<? super R>
downstream) {
this.
parent =
parent;
this.
downstream =
downstream;
}
@
Override
public void
onSubscribe(final
Disposable d) {
DisposableHelper.
replace(
parent,
d);
}
@
Override
public void
onSuccess(final R
value) {
downstream.
onSuccess(
value);
}
@
Override
public void
onError(final
Throwable e) {
downstream.
onError(
e);
}
}
}