/*
* 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.function.
BiPredicate;
import java.util.function.
Function;
import org.reactivestreams.
Subscription;
import reactor.core.
CoreSubscriber;
import reactor.core.
Fuseable.
ConditionalSubscriber;
import reactor.util.annotation.
Nullable;
import reactor.util.context.
Context;
/**
* Filters out subsequent and repeated elements.
*
* @param <T> the value type
* @param <K> the key type used for comparing subsequent elements
* @see <a href="https://github.com/reactor/reactive-streams-commons">Reactive-Streams-Commons</a>
*/
final class
FluxDistinctUntilChanged<T, K> extends
FluxOperator<T, T> {
final
Function<? super T, K>
keyExtractor;
final
BiPredicate<? super K, ? super K>
keyComparator;
FluxDistinctUntilChanged(
Flux<? extends T>
source,
Function<? super T, K>
keyExtractor,
BiPredicate<? super K, ? super K>
keyComparator) {
super(
source);
this.
keyExtractor =
Objects.
requireNonNull(
keyExtractor, "keyExtractor");
this.
keyComparator =
Objects.
requireNonNull(
keyComparator, "keyComparator");
}
@
Override
@
SuppressWarnings("unchecked")
public void
subscribe(
CoreSubscriber<? super T>
actual) {
if (
actual instanceof
ConditionalSubscriber) {
source.
subscribe(new
DistinctUntilChangedConditionalSubscriber<>((
ConditionalSubscriber<? super T>)
actual,
keyExtractor,
keyComparator));
}
else {
source.
subscribe(new
DistinctUntilChangedSubscriber<>(
actual,
keyExtractor,
keyComparator));
}
}
static final class
DistinctUntilChangedSubscriber<T, K>
implements
ConditionalSubscriber<T>,
InnerOperator<T, T> {
final
CoreSubscriber<? super T>
actual;
final
Context ctx;
final
Function<? super T, K>
keyExtractor;
final
BiPredicate<? super K, ? super K>
keyComparator;
Subscription s;
boolean
done;
K
lastKey;
DistinctUntilChangedSubscriber(
CoreSubscriber<? super T>
actual,
Function<? super T, K>
keyExtractor,
BiPredicate<? super K, ? super K>
keyComparator) {
this.
actual =
actual;
this.
ctx =
actual.
currentContext();
this.
keyExtractor =
keyExtractor;
this.
keyComparator =
keyComparator;
}
@
Override
public void
onSubscribe(
Subscription s) {
if (
Operators.
validate(this.
s,
s)) {
this.
s =
s;
actual.
onSubscribe(this);
}
}
@
Override
public void
onNext(T
t) {
if (!
tryOnNext(
t)) {
s.
request(1);
}
}
@
Override
public boolean
tryOnNext(T
t) {
if (
done) {
Operators.
onNextDropped(
t,
ctx);
return true;
}
K
k;
try {
k =
Objects.
requireNonNull(
keyExtractor.
apply(
t),
"The distinct extractor returned a null value.");
}
catch (
Throwable e) {
onError(
Operators.
onOperatorError(
s,
e,
t,
ctx));
Operators.
onDiscard(
t,
ctx);
return true;
}
if (null ==
lastKey) {
lastKey =
k;
actual.
onNext(
t);
return true;
}
boolean
equiv;
try {
equiv =
keyComparator.
test(
lastKey,
k);
}
catch (
Throwable e) {
onError(
Operators.
onOperatorError(
s,
e,
t,
ctx));
Operators.
onDiscard(
t,
ctx);
return true;
}
if (
equiv) {
Operators.
onDiscard(
t,
ctx);
return false;
}
lastKey =
k;
actual.
onNext(
t);
return true;
}
@
Override
public void
onError(
Throwable t) {
if (
done) {
Operators.
onErrorDropped(
t,
ctx);
return;
}
done = true;
actual.
onError(
t);
}
@
Override
public void
onComplete() {
if (
done) {
return;
}
done = true;
actual.
onComplete();
}
@
Override
@
Nullable
public
Object scanUnsafe(
Attr key) {
if (
key ==
Attr.
PARENT) return
s;
if (
key ==
Attr.
TERMINATED) return
done;
return
InnerOperator.super.scanUnsafe(
key);
}
@
Override
public
CoreSubscriber<? super T>
actual() {
return
actual;
}
@
Override
public void
request(long
n) {
s.
request(
n);
}
@
Override
public void
cancel() {
s.
cancel();
}
}
static final class
DistinctUntilChangedConditionalSubscriber<T, K>
implements
ConditionalSubscriber<T>,
InnerOperator<T, T> {
final
ConditionalSubscriber<? super T>
actual;
final
Context ctx;
final
Function<? super T, K>
keyExtractor;
final
BiPredicate<? super K, ? super K>
keyComparator;
Subscription s;
boolean
done;
K
lastKey;
DistinctUntilChangedConditionalSubscriber(
ConditionalSubscriber<? super T>
actual,
Function<? super T, K>
keyExtractor,
BiPredicate<? super K, ? super K>
keyComparator) {
this.
actual =
actual;
this.
ctx =
actual.
currentContext();
this.
keyExtractor =
keyExtractor;
this.
keyComparator =
keyComparator;
}
@
Override
public void
onSubscribe(
Subscription s) {
if (
Operators.
validate(this.
s,
s)) {
this.
s =
s;
actual.
onSubscribe(this);
}
}
@
Override
public void
onNext(T
t) {
if (!
tryOnNext(
t)) {
s.
request(1);
}
}
@
Override
public boolean
tryOnNext(T
t) {
if (
done) {
Operators.
onNextDropped(
t,
ctx);
return true;
}
K
k;
try {
k =
Objects.
requireNonNull(
keyExtractor.
apply(
t),
"The distinct extractor returned a null value.");
}
catch (
Throwable e) {
onError(
Operators.
onOperatorError(
s,
e,
t,
ctx));
Operators.
onDiscard(
t,
ctx);
return true;
}
if (null ==
lastKey) {
lastKey =
k;
return
actual.
tryOnNext(
t);
}
boolean
equiv;
try {
equiv =
keyComparator.
test(
lastKey,
k);
}
catch (
Throwable e) {
onError(
Operators.
onOperatorError(
s,
e,
t,
ctx));
Operators.
onDiscard(
t,
ctx);
return true;
}
if (
equiv) {
Operators.
onDiscard(
t,
ctx);
return false;
}
lastKey =
k;
return
actual.
tryOnNext(
t);
}
@
Override
public void
onError(
Throwable t) {
if (
done) {
Operators.
onErrorDropped(
t,
ctx);
return;
}
done = true;
actual.
onError(
t);
}
@
Override
public void
onComplete() {
if (
done) {
return;
}
done = true;
actual.
onComplete();
}
@
Override
@
Nullable
public
Object scanUnsafe(
Attr key) {
if (
key ==
Attr.
PARENT) return
s;
if (
key ==
Attr.
TERMINATED) return
done;
return
InnerOperator.super.scanUnsafe(
key);
}
@
Override
public
CoreSubscriber<? super T>
actual() {
return
actual;
}
@
Override
public void
request(long
n) {
s.
request(
n);
}
@
Override
public void
cancel() {
s.
cancel();
}
}
}