/*
* 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.publisher;
import java.util.concurrent.
CountDownLatch;
import java.util.concurrent.
TimeUnit;
import org.reactivestreams.
Subscription;
import reactor.core.
Disposable;
import reactor.core.
Exceptions;
import reactor.core.scheduler.
Schedulers;
import reactor.util.annotation.
Nullable;
/**
* @see <a href="https://github.com/reactor/reactive-streams-commons">https://github.com/reactor/reactive-streams-commons</a>
*/
abstract class
BlockingSingleSubscriber<T> extends
CountDownLatch
implements
InnerConsumer<T>,
Disposable {
T
value;
Throwable error;
Subscription s;
volatile boolean
cancelled;
BlockingSingleSubscriber() {
super(1);
}
@
Override
public final void
onSubscribe(
Subscription s) {
this.
s =
s;
if (!
cancelled) {
s.
request(
Long.
MAX_VALUE);
}
}
@
Override
public final void
onComplete() {
countDown();
}
@
Override
public final void
dispose() {
cancelled = true;
Subscription s = this.
s;
if (
s != null) {
this.
s = null;
s.
cancel();
}
}
/**
* Block until the first value arrives and return it, otherwise
* return null for an empty source and rethrow any exception.
*
* @return the first value or null if the source is empty
*/
@
Nullable
final T
blockingGet() {
if (
Schedulers.
isInNonBlockingThread()) {
throw new
IllegalStateException("block()/blockFirst()/blockLast() are blocking, which is not supported in thread " +
Thread.
currentThread().
getName());
}
if (
getCount() != 0) {
try {
await();
}
catch (
InterruptedException ex) {
dispose();
throw
Exceptions.
propagate(
ex);
}
}
Throwable e =
error;
if (
e != null) {
RuntimeException re =
Exceptions.
propagate(
e);
//this is ok, as re is always a new non-singleton instance
re.
addSuppressed(new
Exception("#block terminated with an error"));
throw
re;
}
return
value;
}
/**
* Block until the first value arrives and return it, otherwise
* return null for an empty source and rethrow any exception.
*
* @param timeout the timeout to wait
* @param unit the time unit
*
* @return the first value or null if the source is empty
*/
@
Nullable
final T
blockingGet(long
timeout,
TimeUnit unit) {
if (
Schedulers.
isInNonBlockingThread()) {
throw new
IllegalStateException("block()/blockFirst()/blockLast() are blocking, which is not supported in thread " +
Thread.
currentThread().
getName());
}
if (
getCount() != 0) {
try {
if (!
await(
timeout,
unit)) {
dispose();
throw new
IllegalStateException("Timeout on blocking read for " +
timeout + " " +
unit);
}
}
catch (
InterruptedException ex) {
dispose();
RuntimeException re =
Exceptions.
propagate(
ex);
//this is ok, as re is always a new non-singleton instance
re.
addSuppressed(new
Exception("#block has been interrupted"));
throw
re;
}
}
Throwable e =
error;
if (
e != null) {
RuntimeException re =
Exceptions.
propagate(
e);
//this is ok, as re is always a new non-singleton instance
re.
addSuppressed(new
Exception("#block terminated with an error"));
throw
re;
}
return
value;
}
@
Override
@
Nullable
public
Object scanUnsafe(
Attr key) {
if (
key ==
Attr.
TERMINATED) return
getCount() == 0;
if (
key ==
Attr.
PARENT) return
s;
if (
key ==
Attr.
CANCELLED) return
cancelled;
if (
key ==
Attr.
ERROR) return
error;
if (
key ==
Attr.
PREFETCH) return
Integer.
MAX_VALUE;
return null;
}
@
Override
public boolean
isDisposed() {
return
cancelled ||
getCount() == 0;
}
}