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Reactive Extensions for Java
/**
* 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.mixed;
import java.util.concurrent.atomic.*;
import io.reactivex.*;
import io.reactivex.annotations.Experimental;
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;
import io.reactivex.internal.fuseable.SimplePlainQueue;
import io.reactivex.internal.queue.SpscLinkedArrayQueue;
import io.reactivex.internal.util.*;
import io.reactivex.plugins.RxJavaPlugins;
/**
* Maps each upstream item into a {@link SingleSource}, subscribes to them one after the other terminates
* and relays their success values, optionally delaying any errors till the main and inner sources
* terminate.
*
* @param the upstream element type
* @param the output element type
*
* @since 2.1.11 - experimental
*/
@Experimental
public final class ObservableConcatMapSingle extends Observable {
final Observable source;
final Function> mapper;
final ErrorMode errorMode;
final int prefetch;
public ObservableConcatMapSingle(Observable source,
Function> mapper,
ErrorMode errorMode, int prefetch) {
this.source = source;
this.mapper = mapper;
this.errorMode = errorMode;
this.prefetch = prefetch;
}
@Override
protected void subscribeActual(Observer s) {
if (!ScalarXMapZHelper.tryAsSingle(source, mapper, s)) {
source.subscribe(new ConcatMapSingleMainObserver(s, mapper, prefetch, errorMode));
}
}
static final class ConcatMapSingleMainObserver
extends AtomicInteger
implements Observer, Disposable {
private static final long serialVersionUID = -9140123220065488293L;
final Observer downstream;
final Function> mapper;
final AtomicThrowable errors;
final ConcatMapSingleObserver inner;
final SimplePlainQueue queue;
final ErrorMode errorMode;
Disposable upstream;
volatile boolean done;
volatile boolean cancelled;
R item;
volatile int state;
/** No inner SingleSource is running. */
static final int STATE_INACTIVE = 0;
/** An inner SingleSource is running but there are no results yet. */
static final int STATE_ACTIVE = 1;
/** The inner SingleSource succeeded with a value in {@link #item}. */
static final int STATE_RESULT_VALUE = 2;
ConcatMapSingleMainObserver(Observer downstream,
Function> mapper,
int prefetch, ErrorMode errorMode) {
this.downstream = downstream;
this.mapper = mapper;
this.errorMode = errorMode;
this.errors = new AtomicThrowable();
this.inner = new ConcatMapSingleObserver(this);
this.queue = new SpscLinkedArrayQueue(prefetch);
}
@Override
public void onSubscribe(Disposable s) {
if (DisposableHelper.validate(upstream, s)) {
upstream = s;
downstream.onSubscribe(this);
}
}
@Override
public void onNext(T t) {
queue.offer(t);
drain();
}
@Override
public void onError(Throwable t) {
if (errors.addThrowable(t)) {
if (errorMode == ErrorMode.IMMEDIATE) {
inner.dispose();
}
done = true;
drain();
} else {
RxJavaPlugins.onError(t);
}
}
@Override
public void onComplete() {
done = true;
drain();
}
@Override
public void dispose() {
cancelled = true;
upstream.dispose();
inner.dispose();
if (getAndIncrement() == 0) {
queue.clear();
item = null;
}
}
@Override
public boolean isDisposed() {
return cancelled;
}
void innerSuccess(R item) {
this.item = item;
this.state = STATE_RESULT_VALUE;
drain();
}
void innerError(Throwable ex) {
if (errors.addThrowable(ex)) {
if (errorMode != ErrorMode.END) {
upstream.dispose();
}
this.state = STATE_INACTIVE;
drain();
} else {
RxJavaPlugins.onError(ex);
}
}
void drain() {
if (getAndIncrement() != 0) {
return;
}
int missed = 1;
Observer downstream = this.downstream;
ErrorMode errorMode = this.errorMode;
SimplePlainQueue queue = this.queue;
AtomicThrowable errors = this.errors;
for (;;) {
for (;;) {
if (cancelled) {
queue.clear();
item = null;
break;
}
int s = state;
if (errors.get() != null) {
if (errorMode == ErrorMode.IMMEDIATE
|| (errorMode == ErrorMode.BOUNDARY && s == STATE_INACTIVE)) {
queue.clear();
item = null;
Throwable ex = errors.terminate();
downstream.onError(ex);
return;
}
}
if (s == STATE_INACTIVE) {
boolean d = done;
T v = queue.poll();
boolean empty = v == null;
if (d && empty) {
Throwable ex = errors.terminate();
if (ex == null) {
downstream.onComplete();
} else {
downstream.onError(ex);
}
return;
}
if (empty) {
break;
}
SingleSource ss;
try {
ss = ObjectHelper.requireNonNull(mapper.apply(v), "The mapper returned a null SingleSource");
} catch (Throwable ex) {
Exceptions.throwIfFatal(ex);
upstream.dispose();
queue.clear();
errors.addThrowable(ex);
ex = errors.terminate();
downstream.onError(ex);
return;
}
state = STATE_ACTIVE;
ss.subscribe(inner);
break;
} else if (s == STATE_RESULT_VALUE) {
R w = item;
item = null;
downstream.onNext(w);
state = STATE_INACTIVE;
} else {
break;
}
}
missed = addAndGet(-missed);
if (missed == 0) {
break;
}
}
}
static final class ConcatMapSingleObserver
extends AtomicReference
implements SingleObserver {
private static final long serialVersionUID = -3051469169682093892L;
final ConcatMapSingleMainObserver parent;
ConcatMapSingleObserver(ConcatMapSingleMainObserver parent) {
this.parent = parent;
}
@Override
public void onSubscribe(Disposable d) {
DisposableHelper.replace(this, d);
}
@Override
public void onSuccess(R t) {
parent.innerSuccess(t);
}
@Override
public void onError(Throwable e) {
parent.innerError(e);
}
void dispose() {
DisposableHelper.dispose(this);
}
}
}
}
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