/*
* 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.
Objects;
import java.util.concurrent.atomic.
AtomicLongFieldUpdater;
import java.util.function.
Consumer;
import org.reactivestreams.
Subscription;
import reactor.core.
CoreSubscriber;
import reactor.util.annotation.
Nullable;
import reactor.util.context.
Context;
/**
* Drops values if the subscriber doesn't request fast enough.
*
* @param <T> the value type
* @see <a href="https://github.com/reactor/reactive-streams-commons">Reactive-Streams-Commons</a>
*/
final class
FluxOnBackpressureDrop<T> extends
FluxOperator<T, T> {
static final
Consumer<
Object>
NOOP =
t -> {
};
final
Consumer<? super T>
onDrop;
FluxOnBackpressureDrop(
Flux<? extends T>
source) {
super(
source);
this.
onDrop =
NOOP;
}
FluxOnBackpressureDrop(
Flux<? extends T>
source,
Consumer<? super T>
onDrop) {
super(
source);
this.
onDrop =
Objects.
requireNonNull(
onDrop, "onDrop");
}
@
Override
public int
getPrefetch() {
return
Integer.
MAX_VALUE;
}
@
Override
public void
subscribe(
CoreSubscriber<? super T>
actual) {
source.
subscribe(new
DropSubscriber<>(
actual,
onDrop));
}
static final class
DropSubscriber<T>
implements
InnerOperator<T, T> {
final
CoreSubscriber<? super T>
actual;
final
Context ctx;
final
Consumer<? super T>
onDrop;
Subscription s;
volatile long
requested;
@
SuppressWarnings("rawtypes")
static final
AtomicLongFieldUpdater<
DropSubscriber>
REQUESTED =
AtomicLongFieldUpdater.
newUpdater(
DropSubscriber.class, "requested");
boolean
done;
DropSubscriber(
CoreSubscriber<? super T>
actual,
Consumer<? super T>
onDrop) {
this.
actual =
actual;
this.
ctx =
actual.
currentContext();
this.
onDrop =
onDrop;
}
@
Override
public void
request(long
n) {
if (
Operators.
validate(
n)) {
Operators.
addCap(
REQUESTED, this,
n);
}
}
@
Override
public void
cancel() {
s.
cancel();
}
@
Override
public void
onSubscribe(
Subscription s) {
if (
Operators.
validate(this.
s,
s)) {
this.
s =
s;
actual.
onSubscribe(this);
s.
request(
Long.
MAX_VALUE);
}
}
@
Override
public void
onNext(T
t) {
if (
done) {
try {
onDrop.
accept(
t);
}
catch (
Throwable e) {
Operators.
onErrorDropped(
e,
ctx);
}
Operators.
onDiscard(
t,
ctx);
return;
}
long
r =
requested;
if (
r != 0L) {
actual.
onNext(
t);
if(
r !=
Long.
MAX_VALUE) {
Operators.
produced(
REQUESTED, this, 1);
}
}
else {
try {
onDrop.
accept(
t);
}
catch (
Throwable e) {
onError(
Operators.
onOperatorError(
s,
e,
t,
ctx));
}
Operators.
onDiscard(
t,
ctx);
}
}
@
Override
public void
onError(
Throwable t) {
if (
done) {
Operators.
onErrorDropped(
t,
actual.
currentContext());
return;
}
done = true;
actual.
onError(
t);
}
@
Override
public void
onComplete() {
if (
done) {
return;
}
done = true;
actual.
onComplete();
}
@
Override
public
CoreSubscriber<? super T>
actual() {
return
actual;
}
@
Override
@
Nullable
public
Object scanUnsafe(
Attr key) {
if (
key ==
Attr.
PARENT) return
s;
if (
key ==
Attr.
REQUESTED_FROM_DOWNSTREAM) return
requested;
if (
key ==
Attr.
TERMINATED) return
done;
if (
key ==
Attr.
PREFETCH) return
Integer.
MAX_VALUE;
return
InnerOperator.super.scanUnsafe(
key);
}
}
}