/**
* Copyright (c) 2016-present, RxJava Contributors.
*
* 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 io.reactivex.internal.operators.observable;
import java.util.
ArrayDeque;
import io.reactivex.*;
import io.reactivex.disposables.
Disposable;
import io.reactivex.internal.disposables.
DisposableHelper;
public final class
ObservableTakeLast<T> extends
AbstractObservableWithUpstream<T, T> {
final int
count;
public
ObservableTakeLast(
ObservableSource<T>
source, int
count) {
super(
source);
this.
count =
count;
}
@
Override
public void
subscribeActual(
Observer<? super T>
t) {
source.
subscribe(new
TakeLastObserver<T>(
t,
count));
}
static final class
TakeLastObserver<T> extends
ArrayDeque<T> implements
Observer<T>,
Disposable {
private static final long
serialVersionUID = 7240042530241604978L;
final
Observer<? super T>
downstream;
final int
count;
Disposable upstream;
volatile boolean
cancelled;
TakeLastObserver(
Observer<? super T>
actual, int
count) {
this.
downstream =
actual;
this.
count =
count;
}
@
Override
public void
onSubscribe(
Disposable d) {
if (
DisposableHelper.
validate(this.
upstream,
d)) {
this.
upstream =
d;
downstream.
onSubscribe(this);
}
}
@
Override
public void
onNext(T
t) {
if (
count ==
size()) {
poll();
}
offer(
t);
}
@
Override
public void
onError(
Throwable t) {
downstream.
onError(
t);
}
@
Override
public void
onComplete() {
Observer<? super T>
a =
downstream;
for (;;) {
if (
cancelled) {
return;
}
T
v =
poll();
if (
v == null) {
if (!
cancelled) {
a.
onComplete();
}
return;
}
a.
onNext(
v);
}
}
@
Override
public void
dispose() {
if (!
cancelled) {
cancelled = true;
upstream.
dispose();
}
}
@
Override
public boolean
isDisposed() {
return
cancelled;
}
}
}