org.neo4j.driver.internal.shaded.reactor.core.scheduler.InstantPeriodicWorkerTask Maven / Gradle / Ivy
/*
* Copyright (c) 2017-2021 VMware Inc. or its affiliates, All Rights Reserved.
*
* 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
*
* https://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 reactor.core.scheduler;
import java.util.concurrent.Callable;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Future;
import java.util.concurrent.FutureTask;
import java.util.concurrent.atomic.AtomicReferenceFieldUpdater;
import reactor.core.Disposable;
import reactor.util.annotation.Nullable;
/**
* A runnable task for {@link Scheduler} Workers that can run periodically
**/
final class InstantPeriodicWorkerTask implements Disposable, Callable {
final Runnable task;
final ExecutorService executor;
static final Composite DISPOSED = new EmptyCompositeDisposable();
static final Future CANCELLED = new FutureTask<>(() -> null);
volatile Future rest;
static final AtomicReferenceFieldUpdater REST =
AtomicReferenceFieldUpdater.newUpdater(InstantPeriodicWorkerTask.class, Future.class, "rest");
volatile Future first;
static final AtomicReferenceFieldUpdater FIRST =
AtomicReferenceFieldUpdater.newUpdater(InstantPeriodicWorkerTask.class, Future.class, "first");
volatile Composite parent;
static final AtomicReferenceFieldUpdater PARENT =
AtomicReferenceFieldUpdater.newUpdater(InstantPeriodicWorkerTask.class, Composite.class, "parent");
Thread thread;
InstantPeriodicWorkerTask(Runnable task, ExecutorService executor) {
this.task = task;
this.executor = executor;
}
InstantPeriodicWorkerTask(Runnable task, ExecutorService executor, Composite parent) {
this.task = task;
this.executor = executor;
PARENT.lazySet(this, parent);
}
@Override
@Nullable
public Void call() {
thread = Thread.currentThread();
try {
try {
task.run();
setRest(executor.submit(this));
}
catch (Throwable ex) {
Schedulers.handleError(ex);
}
}
finally {
thread = null;
}
return null;
}
void setRest(Future f) {
for (;;) {
Future o = rest;
if (o == CANCELLED) {
f.cancel(thread != Thread.currentThread());
return;
}
if (REST.compareAndSet(this, o, f)) {
return;
}
}
}
void setFirst(Future f) {
for (;;) {
Future o = first;
if (o == CANCELLED) {
f.cancel(thread != Thread.currentThread());
return;
}
if (FIRST.compareAndSet(this, o, f)) {
return;
}
}
}
@Override
public boolean isDisposed() {
return rest == CANCELLED;
}
@Override
public void dispose() {
for (;;) {
Future f = first;
if (f == CANCELLED) {
break;
}
if (FIRST.compareAndSet(this, f, CANCELLED)) {
if (f != null) {
f.cancel(thread != Thread.currentThread());
}
break;
}
}
for (;;) {
Future f = rest;
if (f == CANCELLED) {
break;
}
if (REST.compareAndSet(this, f, CANCELLED)) {
if (f != null) {
f.cancel(thread != Thread.currentThread());
}
break;
}
}
for (;;) {
Composite o = parent;
if (o == DISPOSED || o == null) {
return;
}
if (PARENT.compareAndSet(this, o, DISPOSED)) {
o.remove(this);
return;
}
}
}
}