TestScheduler.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.rxjava3.schedulers;
import java.util.Queue;
import java.util.concurrent.*;
import java.util.concurrent.atomic.AtomicReference;
import io.reactivex.rxjava3.annotations.*;
import io.reactivex.rxjava3.core.Scheduler;
import io.reactivex.rxjava3.disposables.Disposable;
import io.reactivex.rxjava3.internal.disposables.EmptyDisposable;
import io.reactivex.rxjava3.plugins.RxJavaPlugins;
/**
* A special, non thread-safe scheduler for testing operators that require
* a scheduler without introducing real concurrency and allows manually advancing
* a virtual time.
* <p>
* By default, the tasks submitted via the various {@code schedule} methods are not
* wrapped by the {@link RxJavaPlugins#onSchedule(Runnable)} hook. To enable this behavior,
* create a {@code TestScheduler} via {@link #TestScheduler(boolean)} or {@link #TestScheduler(long, TimeUnit, boolean)}.
*/
public final class TestScheduler extends Scheduler {
/** The ordered queue for the runnable tasks. */
final Queue<TimedRunnable> queue = new PriorityBlockingQueue<>(11);
/** Use the {@link RxJavaPlugins#onSchedule(Runnable)} hook when scheduling tasks. */
final boolean useOnScheduleHook;
/** The per-scheduler global order counter. */
long counter;
// Storing time in nanoseconds internally.
volatile long time;
/**
* Creates a new TestScheduler with initial virtual time of zero.
*/
public TestScheduler() {
this(false);
}
/**
* Creates a new TestScheduler with the option to use the
* {@link RxJavaPlugins#onSchedule(Runnable)} hook when scheduling tasks.
* <p>History: 3.0.10 - experimental
* @param useOnScheduleHook if {@code true}, the tasks submitted to this
* TestScheduler is wrapped via the
* {@link RxJavaPlugins#onSchedule(Runnable)} hook
* @since 3.1.0
*/
public TestScheduler(boolean useOnScheduleHook) {
this.useOnScheduleHook = useOnScheduleHook;
}
/**
* Creates a new TestScheduler with the specified initial virtual time.
*
* @param delayTime
* the point in time to move the Scheduler's clock to
* @param unit
* the units of time that {@code delayTime} is expressed in
*/
public TestScheduler(long delayTime, TimeUnit unit) {
this(delayTime, unit, false);
}
/**
* Creates a new TestScheduler with the specified initial virtual time
* and with the option to use the
* {@link RxJavaPlugins#onSchedule(Runnable)} hook when scheduling tasks.
* <p>History: 3.0.10 - experimental
* @param delayTime
* the point in time to move the Scheduler's clock to
* @param unit
* the units of time that {@code delayTime} is expressed in
* @param useOnScheduleHook if {@code true}, the tasks submitted to this
* TestScheduler is wrapped via the
* {@link RxJavaPlugins#onSchedule(Runnable)} hook
* @since 3.1.0
*/
public TestScheduler(long delayTime, TimeUnit unit, boolean useOnScheduleHook) {
time = unit.toNanos(delayTime);
this.useOnScheduleHook = useOnScheduleHook;
}
static final class TimedRunnable implements Comparable<TimedRunnable> {
final long time;
final Runnable run;
final TestWorker scheduler;
final long count; // for differentiating tasks at same time
TimedRunnable(TestWorker scheduler, long time, Runnable run, long count) {
this.time = time;
this.run = run;
this.scheduler = scheduler;
this.count = count;
}
@Override
public String toString() {
return String.format("TimedRunnable(time = %d, run = %s)", time, run.toString());
}
@Override
public int compareTo(TimedRunnable o) {
if (time == o.time) {
return Long.compare(count, o.count);
}
return Long.compare(time, o.time);
}
}
@Override
public long now(@NonNull TimeUnit unit) {
return unit.convert(time, TimeUnit.NANOSECONDS);
}
/**
* Moves the Scheduler's clock forward by a specified amount of time.
*
* @param delayTime
* the amount of time to move the Scheduler's clock forward
* @param unit
* the units of time that {@code delayTime} is expressed in
*/
public void advanceTimeBy(long delayTime, TimeUnit unit) {
advanceTimeTo(time + unit.toNanos(delayTime), TimeUnit.NANOSECONDS);
}
/**
* Moves the Scheduler's clock to a particular moment in time.
*
* @param delayTime
* the point in time to move the Scheduler's clock to
* @param unit
* the units of time that {@code delayTime} is expressed in
*/
public void advanceTimeTo(long delayTime, TimeUnit unit) {
long targetTime = unit.toNanos(delayTime);
triggerActions(targetTime);
}
/**
* Triggers any actions that have not yet been triggered and that are scheduled to be triggered at or
* before this Scheduler's present time.
*/
public void triggerActions() {
triggerActions(time);
}
private void triggerActions(long targetTimeInNanoseconds) {
for (;;) {
TimedRunnable current = queue.peek();
if (current == null || current.time > targetTimeInNanoseconds) {
break;
}
// if scheduled time is 0 (immediate) use current virtual time
time = current.time == 0 ? time : current.time;
queue.remove(current);
// Only execute if not unsubscribed
if (!current.scheduler.disposed) {
current.run.run();
}
}
time = targetTimeInNanoseconds;
}
@NonNull
@Override
public Worker createWorker() {
return new TestWorker();
}
final class TestWorker extends Worker {
volatile boolean disposed;
@Override
public void dispose() {
disposed = true;
}
@Override
public boolean isDisposed() {
return disposed;
}
@NonNull
@Override
public Disposable schedule(@NonNull Runnable run, long delayTime, @NonNull TimeUnit unit) {
if (disposed) {
return EmptyDisposable.INSTANCE;
}
if (useOnScheduleHook) {
run = RxJavaPlugins.onSchedule(run);
}
final TimedRunnable timedAction = new TimedRunnable(this, time + unit.toNanos(delayTime), run, counter++);
queue.add(timedAction);
return new QueueRemove(timedAction);
}
@NonNull
@Override
public Disposable schedule(@NonNull Runnable run) {
if (disposed) {
return EmptyDisposable.INSTANCE;
}
if (useOnScheduleHook) {
run = RxJavaPlugins.onSchedule(run);
}
final TimedRunnable timedAction = new TimedRunnable(this, 0, run, counter++);
queue.add(timedAction);
return new QueueRemove(timedAction);
}
@Override
public long now(@NonNull TimeUnit unit) {
return TestScheduler.this.now(unit);
}
final class QueueRemove extends AtomicReference<TimedRunnable> implements Disposable {
private static final long serialVersionUID = -7874968252110604360L;
QueueRemove(TimedRunnable timedAction) {
this.lazySet(timedAction);
}
@Override
public void dispose() {
TimedRunnable tr = getAndSet(null);
if (tr != null) {
queue.remove(tr);
}
}
@Override
public boolean isDisposed() {
return get() == null;
}
}
}
}