/*
* Copyright (c) 2011-2017 Pivotal Software Inc, 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
*
* 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 reactor.core.scheduler;
import java.util.concurrent.
Callable;
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;
final class
SchedulerTask implements
Runnable,
Disposable,
Callable<
Void> {
final
Runnable task;
static final
Future<
Void>
FINISHED = new
FutureTask<>(() -> null);
static final
Future<
Void>
CANCELLED = new
FutureTask<>(() -> null);
volatile
Future<?>
future;
static final
AtomicReferenceFieldUpdater<
SchedulerTask,
Future>
FUTURE =
AtomicReferenceFieldUpdater.
newUpdater(
SchedulerTask.class,
Future.class, "future");
Thread thread;
SchedulerTask(
Runnable task) {
this.
task =
task;
}
@
Override
@
Nullable
public
Void call() {
thread =
Thread.
currentThread();
try {
try {
task.
run();
}
catch (
Throwable ex) {
Schedulers.
handleError(
ex);
}
}
finally {
thread = null;
Future f;
for (;;) {
f =
future;
if (
f ==
CANCELLED ||
FUTURE.
compareAndSet(this,
f,
FINISHED)) {
break;
}
}
}
return null;
}
@
Override
public void
run() {
call();
}
void
setFuture(
Future<?>
f) {
for (;;) {
Future o =
future;
if (
o ==
FINISHED) {
return;
}
if (
o ==
CANCELLED) {
f.
cancel(
thread !=
Thread.
currentThread());
return;
}
if (
FUTURE.
compareAndSet(this,
o,
f)) {
return;
}
}
}
@
Override
public boolean
isDisposed() {
Future<?>
a =
future;
return
FINISHED ==
a ||
CANCELLED ==
a;
}
@
Override
public void
dispose() {
for (;;) {
Future f =
future;
if (
f ==
FINISHED ||
f ==
CANCELLED) {
break;
}
if (
FUTURE.
compareAndSet(this,
f,
CANCELLED)) {
if (
f != null) {
f.
cancel(
thread !=
Thread.
currentThread());
}
break;
}
}
}
}