/**
* 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.subjects;
import java.lang.reflect.
Array;
import java.util.*;
import java.util.concurrent.
TimeUnit;
import java.util.concurrent.atomic.*;
import io.reactivex.
Observer;
import io.reactivex.
Scheduler;
import io.reactivex.annotations.*;
import io.reactivex.disposables.
Disposable;
import io.reactivex.internal.functions.
ObjectHelper;
import io.reactivex.internal.util.
NotificationLite;
import io.reactivex.plugins.
RxJavaPlugins;
/**
* Replays events (in a configurable bounded or unbounded manner) to current and late {@link Observer}s.
* <p>
* This subject does not have a public constructor by design; a new empty instance of this
* {@code ReplaySubject} can be created via the following {@code create} methods that
* allow specifying the retention policy for items:
* <ul>
* <li>{@link #create()} - creates an empty, unbounded {@code ReplaySubject} that
* caches all items and the terminal event it receives.
* <p>
* <img width="640" height="299" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/ReplaySubject.u.png" alt="">
* <p>
* <img width="640" height="398" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/ReplaySubject.ue.png" alt="">
* </li>
* <li>{@link #create(int)} - creates an empty, unbounded {@code ReplaySubject}
* with a hint about how many <b>total</b> items one expects to retain.
* </li>
* <li>{@link #createWithSize(int)} - creates an empty, size-bound {@code ReplaySubject}
* that retains at most the given number of the latest item it receives.
* <p>
* <img width="640" height="420" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/ReplaySubject.n.png" alt="">
* </li>
* <li>{@link #createWithTime(long, TimeUnit, Scheduler)} - creates an empty, time-bound
* {@code ReplaySubject} that retains items no older than the specified time amount.
* <p>
* <img width="640" height="415" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/ReplaySubject.t.png" alt="">
* </li>
* <li>{@link #createWithTimeAndSize(long, TimeUnit, Scheduler, int)} - creates an empty,
* time- and size-bound {@code ReplaySubject} that retains at most the given number
* items that are also not older than the specified time amount.
* <p>
* <img width="640" height="404" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/ReplaySubject.nt.png" alt="">
* </li>
* </ul>
* <p>
* Since a {@code Subject} is conceptionally derived from the {@code Processor} type in the Reactive Streams specification,
* {@code null}s are not allowed (<a href="https://github.com/reactive-streams/reactive-streams-jvm#2.13">Rule 2.13</a>) as
* parameters to {@link #onNext(Object)} and {@link #onError(Throwable)}. Such calls will result in a
* {@link NullPointerException} being thrown and the subject's state is not changed.
* <p>
* Since a {@code ReplaySubject} is an {@link io.reactivex.Observable}, it does not support backpressure.
* <p>
* When this {@code ReplaySubject} is terminated via {@link #onError(Throwable)} or {@link #onComplete()},
* late {@link io.reactivex.Observer}s will receive the retained/cached items first (if any) followed by the respective
* terminal event. If the {@code ReplaySubject} has a time-bound, the age of the retained/cached items are still considered
* when replaying and thus it may result in no items being emitted before the terminal event.
* <p>
* Once an {@code Observer} has subscribed, it will receive items continuously from that point on. Bounds only affect how
* many past items a new {@code Observer} will receive before it catches up with the live event feed.
* <p>
* Even though {@code ReplaySubject} implements the {@code Observer} interface, calling
* {@code onSubscribe} is not required (<a href="https://github.com/reactive-streams/reactive-streams-jvm#2.12">Rule 2.12</a>)
* if the subject is used as a standalone source. However, calling {@code onSubscribe}
* after the {@code ReplaySubject} reached its terminal state will result in the
* given {@code Disposable} being disposed immediately.
* <p>
* Calling {@link #onNext(Object)}, {@link #onError(Throwable)} and {@link #onComplete()}
* is required to be serialized (called from the same thread or called non-overlappingly from different threads
* through external means of serialization). The {@link #toSerialized()} method available to all {@code Subject}s
* provides such serialization and also protects against reentrance (i.e., when a downstream {@code Observer}
* consuming this subject also wants to call {@link #onNext(Object)} on this subject recursively).
* <p>
* This {@code ReplaySubject} supports the standard state-peeking methods {@link #hasComplete()}, {@link #hasThrowable()},
* {@link #getThrowable()} and {@link #hasObservers()} as well as means to read the retained/cached items
* in a non-blocking and thread-safe manner via {@link #hasValue()}, {@link #getValue()},
* {@link #getValues()} or {@link #getValues(Object[])}.
* <p>
* Note that due to concurrency requirements, a size- and time-bounded {@code ReplaySubject} may hold strong references to more
* source emissions than specified while it isn't terminated yet. Use the {@link #cleanupBuffer()} to allow
* such inaccessible items to be cleaned up by GC once no consumer references it anymore.
* <dl>
* <dt><b>Scheduler:</b></dt>
* <dd>{@code ReplaySubject} does not operate by default on a particular {@link io.reactivex.Scheduler} and
* the {@code Observer}s get notified on the thread the respective {@code onXXX} methods were invoked.
* Time-bound {@code ReplaySubject}s use the given {@code Scheduler} in their {@code create} methods
* as time source to timestamp of items received for the age checks.</dd>
* <dt><b>Error handling:</b></dt>
* <dd>When the {@link #onError(Throwable)} is called, the {@code ReplaySubject} enters into a terminal state
* and emits the same {@code Throwable} instance to the last set of {@code Observer}s. During this emission,
* if one or more {@code Observer}s dispose their respective {@code Disposable}s, the
* {@code Throwable} is delivered to the global error handler via
* {@link io.reactivex.plugins.RxJavaPlugins#onError(Throwable)} (multiple times if multiple {@code Observer}s
* cancel at once).
* If there were no {@code Observer}s subscribed to this {@code ReplaySubject} when the {@code onError()}
* was called, the global error handler is not invoked.
* </dd>
* </dl>
* <p>
* Example usage:
* <pre> {@code
ReplaySubject<Object> subject = ReplaySubject.create();
subject.onNext("one");
subject.onNext("two");
subject.onNext("three");
subject.onComplete();
// both of the following will get the onNext/onComplete calls from above
subject.subscribe(observer1);
subject.subscribe(observer2);
} </pre>
*
* @param <T> the value type
*/
public final class
ReplaySubject<T> extends
Subject<T> {
final
ReplayBuffer<T>
buffer;
final
AtomicReference<
ReplayDisposable<T>[]>
observers;
@
SuppressWarnings("rawtypes")
static final
ReplayDisposable[]
EMPTY = new
ReplayDisposable[0];
@
SuppressWarnings("rawtypes")
static final
ReplayDisposable[]
TERMINATED = new
ReplayDisposable[0];
boolean
done;
/**
* Creates an unbounded replay subject.
* <p>
* The internal buffer is backed by an {@link ArrayList} and starts with an initial capacity of 16. Once the
* number of items reaches this capacity, it will grow as necessary (usually by 50%). However, as the
* number of items grows, this causes frequent array reallocation and copying, and may hurt performance
* and latency. This can be avoided with the {@link #create(int)} overload which takes an initial capacity
* parameter and can be tuned to reduce the array reallocation frequency as needed.
*
* @param <T>
* the type of items observed and emitted by the Subject
* @return the created subject
*/
@
CheckReturnValue
@
NonNull
public static <T>
ReplaySubject<T>
create() {
return new
ReplaySubject<T>(new
UnboundedReplayBuffer<T>(16));
}
/**
* Creates an unbounded replay subject with the specified initial buffer capacity.
* <p>
* Use this method to avoid excessive array reallocation while the internal buffer grows to accommodate new
* items. For example, if you know that the buffer will hold 32k items, you can ask the
* {@code ReplaySubject} to preallocate its internal array with a capacity to hold that many items. Once
* the items start to arrive, the internal array won't need to grow, creating less garbage and no overhead
* due to frequent array-copying.
*
* @param <T>
* the type of items observed and emitted by the Subject
* @param capacityHint
* the initial buffer capacity
* @return the created subject
*/
@
CheckReturnValue
@
NonNull
public static <T>
ReplaySubject<T>
create(int
capacityHint) {
return new
ReplaySubject<T>(new
UnboundedReplayBuffer<T>(
capacityHint));
}
/**
* Creates a size-bounded replay subject.
* <p>
* In this setting, the {@code ReplaySubject} holds at most {@code size} items in its internal buffer and
* discards the oldest item.
* <p>
* When observers subscribe to a terminated {@code ReplaySubject}, they are guaranteed to see at most
* {@code size} {@code onNext} events followed by a termination event.
* <p>
* If an observer subscribes while the {@code ReplaySubject} is active, it will observe all items in the
* buffer at that point in time and each item observed afterwards, even if the buffer evicts items due to
* the size constraint in the mean time. In other words, once an Observer subscribes, it will receive items
* without gaps in the sequence.
*
* @param <T>
* the type of items observed and emitted by the Subject
* @param maxSize
* the maximum number of buffered items
* @return the created subject
*/
@
CheckReturnValue
@
NonNull
public static <T>
ReplaySubject<T>
createWithSize(int
maxSize) {
return new
ReplaySubject<T>(new
SizeBoundReplayBuffer<T>(
maxSize));
}
/**
* Creates an unbounded replay subject with the bounded-implementation for testing purposes.
* <p>
* This variant behaves like the regular unbounded {@code ReplaySubject} created via {@link #create()} but
* uses the structures of the bounded-implementation. This is by no means intended for the replacement of
* the original, array-backed and unbounded {@code ReplaySubject} due to the additional overhead of the
* linked-list based internal buffer. The sole purpose is to allow testing and reasoning about the behavior
* of the bounded implementations without the interference of the eviction policies.
*
* @param <T>
* the type of items observed and emitted by the Subject
* @return the created subject
*/
/* test */ static <T>
ReplaySubject<T>
createUnbounded() {
return new
ReplaySubject<T>(new
SizeBoundReplayBuffer<T>(
Integer.
MAX_VALUE));
}
/**
* Creates a time-bounded replay subject.
* <p>
* In this setting, the {@code ReplaySubject} internally tags each observed item with a timestamp value
* supplied by the {@link Scheduler} and keeps only those whose age is less than the supplied time value
* converted to milliseconds. For example, an item arrives at T=0 and the max age is set to 5; at T>=5
* this first item is then evicted by any subsequent item or termination event, leaving the buffer empty.
* <p>
* Once the subject is terminated, observers subscribing to it will receive items that remained in the
* buffer after the terminal event, regardless of their age.
* <p>
* If an observer subscribes while the {@code ReplaySubject} is active, it will observe only those items
* from within the buffer that have an age less than the specified time, and each item observed thereafter,
* even if the buffer evicts items due to the time constraint in the mean time. In other words, once an
* observer subscribes, it observes items without gaps in the sequence except for any outdated items at the
* beginning of the sequence.
* <p>
* Note that terminal notifications ({@code onError} and {@code onComplete}) trigger eviction as well. For
* example, with a max age of 5, the first item is observed at T=0, then an {@code onComplete} notification
* arrives at T=10. If an observer subscribes at T=11, it will find an empty {@code ReplaySubject} with just
* an {@code onComplete} notification.
*
* @param <T>
* the type of items observed and emitted by the Subject
* @param maxAge
* the maximum age of the contained items
* @param unit
* the time unit of {@code time}
* @param scheduler
* the {@link Scheduler} that provides the current time
* @return the created subject
*/
@
CheckReturnValue
@
NonNull
public static <T>
ReplaySubject<T>
createWithTime(long
maxAge,
TimeUnit unit,
Scheduler scheduler) {
return new
ReplaySubject<T>(new
SizeAndTimeBoundReplayBuffer<T>(
Integer.
MAX_VALUE,
maxAge,
unit,
scheduler));
}
/**
* Creates a time- and size-bounded replay subject.
* <p>
* In this setting, the {@code ReplaySubject} internally tags each received item with a timestamp value
* supplied by the {@link Scheduler} and holds at most {@code size} items in its internal buffer. It evicts
* items from the start of the buffer if their age becomes less-than or equal to the supplied age in
* milliseconds or the buffer reaches its {@code size} limit.
* <p>
* When observers subscribe to a terminated {@code ReplaySubject}, they observe the items that remained in
* the buffer after the terminal notification, regardless of their age, but at most {@code size} items.
* <p>
* If an observer subscribes while the {@code ReplaySubject} is active, it will observe only those items
* from within the buffer that have age less than the specified time and each subsequent item, even if the
* buffer evicts items due to the time constraint in the mean time. In other words, once an observer
* subscribes, it observes items without gaps in the sequence except for the outdated items at the beginning
* of the sequence.
* <p>
* Note that terminal notifications ({@code onError} and {@code onComplete}) trigger eviction as well. For
* example, with a max age of 5, the first item is observed at T=0, then an {@code onComplete} notification
* arrives at T=10. If an observer subscribes at T=11, it will find an empty {@code ReplaySubject} with just
* an {@code onComplete} notification.
*
* @param <T>
* the type of items observed and emitted by the Subject
* @param maxAge
* the maximum age of the contained items
* @param unit
* the time unit of {@code time}
* @param maxSize
* the maximum number of buffered items
* @param scheduler
* the {@link Scheduler} that provides the current time
* @return the created subject
*/
@
CheckReturnValue
@
NonNull
public static <T>
ReplaySubject<T>
createWithTimeAndSize(long
maxAge,
TimeUnit unit,
Scheduler scheduler, int
maxSize) {
return new
ReplaySubject<T>(new
SizeAndTimeBoundReplayBuffer<T>(
maxSize,
maxAge,
unit,
scheduler));
}
/**
* Constructs a ReplayProcessor with the given custom ReplayBuffer instance.
* @param buffer the ReplayBuffer instance, not null (not verified)
*/
@
SuppressWarnings("unchecked")
ReplaySubject(
ReplayBuffer<T>
buffer) {
this.
buffer =
buffer;
this.
observers = new
AtomicReference<
ReplayDisposable<T>[]>(
EMPTY);
}
@
Override
protected void
subscribeActual(
Observer<? super T>
observer) {
ReplayDisposable<T>
rs = new
ReplayDisposable<T>(
observer, this);
observer.
onSubscribe(
rs);
if (!
rs.
cancelled) {
if (
add(
rs)) {
if (
rs.
cancelled) {
remove(
rs);
return;
}
}
buffer.
replay(
rs);
}
}
@
Override
public void
onSubscribe(
Disposable d) {
if (
done) {
d.
dispose();
}
}
@
Override
public void
onNext(T
t) {
ObjectHelper.
requireNonNull(
t, "onNext called with null. Null values are generally not allowed in 2.x operators and sources.");
if (
done) {
return;
}
ReplayBuffer<T>
b =
buffer;
b.
add(
t);
for (
ReplayDisposable<T>
rs :
observers.
get()) {
b.
replay(
rs);
}
}
@
Override
public void
onError(
Throwable t) {
ObjectHelper.
requireNonNull(
t, "onError called with null. Null values are generally not allowed in 2.x operators and sources.");
if (
done) {
RxJavaPlugins.
onError(
t);
return;
}
done = true;
Object o =
NotificationLite.
error(
t);
ReplayBuffer<T>
b =
buffer;
b.
addFinal(
o);
for (
ReplayDisposable<T>
rs :
terminate(
o)) {
b.
replay(
rs);
}
}
@
Override
public void
onComplete() {
if (
done) {
return;
}
done = true;
Object o =
NotificationLite.
complete();
ReplayBuffer<T>
b =
buffer;
b.
addFinal(
o);
for (
ReplayDisposable<T>
rs :
terminate(
o)) {
b.
replay(
rs);
}
}
@
Override
public boolean
hasObservers() {
return
observers.
get().length != 0;
}
/* test */ int
observerCount() {
return
observers.
get().length;
}
@
Override
@
Nullable
public
Throwable getThrowable() {
Object o =
buffer.
get();
if (
NotificationLite.
isError(
o)) {
return
NotificationLite.
getError(
o);
}
return null;
}
/**
* Returns a single value the Subject currently has or null if no such value exists.
* <p>The method is thread-safe.
* @return a single value the Subject currently has or null if no such value exists
*/
@
Nullable
public T
getValue() {
return
buffer.
getValue();
}
/**
* Makes sure the item cached by the head node in a bounded
* ReplaySubject is released (as it is never part of a replay).
* <p>
* By default, live bounded buffers will remember one item before
* the currently receivable one to ensure subscribers can always
* receive a continuous sequence of items. A terminated ReplaySubject
* automatically releases this inaccessible item.
* <p>
* The method must be called sequentially, similar to the standard
* {@code onXXX} methods.
* <p>History: 2.1.11 - experimental
* @since 2.2
*/
public void
cleanupBuffer() {
buffer.
trimHead();
}
/** An empty array to avoid allocation in getValues(). */
private static final
Object[]
EMPTY_ARRAY = new
Object[0];
/**
* Returns an Object array containing snapshot all values of the Subject.
* <p>The method is thread-safe.
* @return the array containing the snapshot of all values of the Subject
*/
public
Object[]
getValues() {
@
SuppressWarnings("unchecked")
T[]
a = (T[])
EMPTY_ARRAY;
T[]
b =
getValues(
a);
if (
b ==
EMPTY_ARRAY) {
return new
Object[0];
}
return
b;
}
/**
* Returns a typed array containing a snapshot of all values of the Subject.
* <p>The method follows the conventions of Collection.toArray by setting the array element
* after the last value to null (if the capacity permits).
* <p>The method is thread-safe.
* @param array the target array to copy values into if it fits
* @return the given array if the values fit into it or a new array containing all values
*/
public T[]
getValues(T[]
array) {
return
buffer.
getValues(
array);
}
@
Override
public boolean
hasComplete() {
Object o =
buffer.
get();
return
NotificationLite.
isComplete(
o);
}
@
Override
public boolean
hasThrowable() {
Object o =
buffer.
get();
return
NotificationLite.
isError(
o);
}
/**
* Returns true if the subject has any value.
* <p>The method is thread-safe.
* @return true if the subject has any value
*/
public boolean
hasValue() {
return
buffer.
size() != 0; // NOPMD
}
/* test*/ int
size() {
return
buffer.
size();
}
boolean
add(
ReplayDisposable<T>
rs) {
for (;;) {
ReplayDisposable<T>[]
a =
observers.
get();
if (
a ==
TERMINATED) {
return false;
}
int
len =
a.length;
@
SuppressWarnings("unchecked")
ReplayDisposable<T>[]
b = new
ReplayDisposable[
len + 1];
System.
arraycopy(
a, 0,
b, 0,
len);
b[
len] =
rs;
if (
observers.
compareAndSet(
a,
b)) {
return true;
}
}
}
@
SuppressWarnings("unchecked")
void
remove(
ReplayDisposable<T>
rs) {
for (;;) {
ReplayDisposable<T>[]
a =
observers.
get();
if (
a ==
TERMINATED ||
a ==
EMPTY) {
return;
}
int
len =
a.length;
int
j = -1;
for (int
i = 0;
i <
len;
i++) {
if (
a[
i] ==
rs) {
j =
i;
break;
}
}
if (
j < 0) {
return;
}
ReplayDisposable<T>[]
b;
if (
len == 1) {
b =
EMPTY;
} else {
b = new
ReplayDisposable[
len - 1];
System.
arraycopy(
a, 0,
b, 0,
j);
System.
arraycopy(
a,
j + 1,
b,
j,
len -
j - 1);
}
if (
observers.
compareAndSet(
a,
b)) {
return;
}
}
}
@
SuppressWarnings("unchecked")
ReplayDisposable<T>[]
terminate(
Object terminalValue) {
if (
buffer.
compareAndSet(null,
terminalValue)) {
return
observers.
getAndSet(
TERMINATED);
}
return
TERMINATED;
}
/**
* Abstraction over a buffer that receives events and replays them to
* individual Observers.
*
* @param <T> the value type
*/
interface
ReplayBuffer<T> {
void
add(T
value);
void
addFinal(
Object notificationLite);
void
replay(
ReplayDisposable<T>
rs);
int
size();
@
Nullable
T
getValue();
T[]
getValues(T[]
array);
/**
* Returns the terminal NotificationLite object or null if not yet terminated.
* @return the terminal NotificationLite object or null if not yet terminated
*/
Object get();
/**
* Atomically compares and sets the next terminal NotificationLite object if the
* current equals to the expected NotificationLite object.
* @param expected the expected NotificationLite object
* @param next the next NotificationLite object
* @return true if successful
*/
boolean
compareAndSet(
Object expected,
Object next);
/**
* Make sure an old inaccessible head value is released
* in a bounded buffer.
*/
void
trimHead();
}
static final class
ReplayDisposable<T> extends
AtomicInteger implements
Disposable {
private static final long
serialVersionUID = 466549804534799122L;
final
Observer<? super T>
downstream;
final
ReplaySubject<T>
state;
Object index;
volatile boolean
cancelled;
ReplayDisposable(
Observer<? super T>
actual,
ReplaySubject<T>
state) {
this.
downstream =
actual;
this.
state =
state;
}
@
Override
public void
dispose() {
if (!
cancelled) {
cancelled = true;
state.
remove(this);
}
}
@
Override
public boolean
isDisposed() {
return
cancelled;
}
}
static final class
UnboundedReplayBuffer<T>
extends
AtomicReference<
Object>
implements
ReplayBuffer<T> {
private static final long
serialVersionUID = -733876083048047795L;
final
List<
Object>
buffer;
volatile boolean
done;
volatile int
size;
UnboundedReplayBuffer(int
capacityHint) {
this.
buffer = new
ArrayList<
Object>(
ObjectHelper.
verifyPositive(
capacityHint, "capacityHint"));
}
@
Override
public void
add(T
value) {
buffer.
add(
value);
size++;
}
@
Override
public void
addFinal(
Object notificationLite) {
buffer.
add(
notificationLite);
trimHead();
size++;
done = true;
}
@
Override
public void
trimHead() {
// no-op in this type of buffer
}
@
Override
@
Nullable
@
SuppressWarnings("unchecked")
public T
getValue() {
int
s =
size;
if (
s != 0) {
List<
Object>
b =
buffer;
Object o =
b.
get(
s - 1);
if (
NotificationLite.
isComplete(
o) ||
NotificationLite.
isError(
o)) {
if (
s == 1) {
return null;
}
return (T)
b.
get(
s - 2);
}
return (T)
o;
}
return null;
}
@
Override
@
SuppressWarnings("unchecked")
public T[]
getValues(T[]
array) {
int
s =
size;
if (
s == 0) {
if (
array.length != 0) {
array[0] = null;
}
return
array;
}
List<
Object>
b =
buffer;
Object o =
b.
get(
s - 1);
if (
NotificationLite.
isComplete(
o) ||
NotificationLite.
isError(
o)) {
s--;
if (
s == 0) {
if (
array.length != 0) {
array[0] = null;
}
return
array;
}
}
if (
array.length <
s) {
array = (T[])
Array.
newInstance(
array.
getClass().
getComponentType(),
s);
}
for (int
i = 0;
i <
s;
i++) {
array[
i] = (T)
b.
get(
i);
}
if (
array.length >
s) {
array[
s] = null;
}
return
array;
}
@
Override
@
SuppressWarnings("unchecked")
public void
replay(
ReplayDisposable<T>
rs) {
if (
rs.
getAndIncrement() != 0) {
return;
}
int
missed = 1;
final
List<
Object>
b =
buffer;
final
Observer<? super T>
a =
rs.
downstream;
Integer indexObject = (
Integer)
rs.
index;
int
index;
if (
indexObject != null) {
index =
indexObject;
} else {
index = 0;
rs.
index = 0;
}
for (;;) {
if (
rs.
cancelled) {
rs.
index = null;
return;
}
int
s =
size;
while (
s !=
index) {
if (
rs.
cancelled) {
rs.
index = null;
return;
}
Object o =
b.
get(
index);
if (
done) {
if (
index + 1 ==
s) {
s =
size;
if (
index + 1 ==
s) {
if (
NotificationLite.
isComplete(
o)) {
a.
onComplete();
} else {
a.
onError(
NotificationLite.
getError(
o));
}
rs.
index = null;
rs.
cancelled = true;
return;
}
}
}
a.
onNext((T)
o);
index++;
}
if (
index !=
size) {
continue;
}
rs.
index =
index;
missed =
rs.
addAndGet(-
missed);
if (
missed == 0) {
break;
}
}
}
@
Override
public int
size() {
int
s =
size;
if (
s != 0) {
Object o =
buffer.
get(
s - 1);
if (
NotificationLite.
isComplete(
o) ||
NotificationLite.
isError(
o)) {
return
s - 1;
}
return
s;
}
return 0;
}
}
static final class
Node<T> extends
AtomicReference<
Node<T>> {
private static final long
serialVersionUID = 6404226426336033100L;
final T
value;
Node(T
value) {
this.
value =
value;
}
}
static final class
TimedNode<T> extends
AtomicReference<
TimedNode<T>> {
private static final long
serialVersionUID = 6404226426336033100L;
final T
value;
final long
time;
TimedNode(T
value, long
time) {
this.
value =
value;
this.
time =
time;
}
}
static final class
SizeBoundReplayBuffer<T>
extends
AtomicReference<
Object>
implements
ReplayBuffer<T> {
private static final long
serialVersionUID = 1107649250281456395L;
final int
maxSize;
int
size;
volatile
Node<
Object>
head;
Node<
Object>
tail;
volatile boolean
done;
SizeBoundReplayBuffer(int
maxSize) {
this.
maxSize =
ObjectHelper.
verifyPositive(
maxSize, "maxSize");
Node<
Object>
h = new
Node<
Object>(null);
this.
tail =
h;
this.
head =
h;
}
void
trim() {
if (
size >
maxSize) {
size--;
Node<
Object>
h =
head;
head =
h.
get();
}
}
@
Override
public void
add(T
value) {
Node<
Object>
n = new
Node<
Object>(
value);
Node<
Object>
t =
tail;
tail =
n;
size++;
t.
set(
n); // releases both the tail and size
trim();
}
@
Override
public void
addFinal(
Object notificationLite) {
Node<
Object>
n = new
Node<
Object>(
notificationLite);
Node<
Object>
t =
tail;
tail =
n;
size++;
t.
lazySet(
n); // releases both the tail and size
trimHead();
done = true;
}
/**
* Replace a non-empty head node with an empty one to
* allow the GC of the inaccessible old value.
*/
@
Override
public void
trimHead() {
Node<
Object>
h =
head;
if (
h.
value != null) {
Node<
Object>
n = new
Node<
Object>(null);
n.
lazySet(
h.
get());
head =
n;
}
}
@
Override
@
Nullable
@
SuppressWarnings("unchecked")
public T
getValue() {
Node<
Object>
prev = null;
Node<
Object>
h =
head;
for (;;) {
Node<
Object>
next =
h.
get();
if (
next == null) {
break;
}
prev =
h;
h =
next;
}
Object v =
h.
value;
if (
v == null) {
return null;
}
if (
NotificationLite.
isComplete(
v) ||
NotificationLite.
isError(
v)) {
return (T)
prev.
value;
}
return (T)
v;
}
@
Override
@
SuppressWarnings("unchecked")
public T[]
getValues(T[]
array) {
Node<
Object>
h =
head;
int
s =
size();
if (
s == 0) {
if (
array.length != 0) {
array[0] = null;
}
} else {
if (
array.length <
s) {
array = (T[])
Array.
newInstance(
array.
getClass().
getComponentType(),
s);
}
int
i = 0;
while (
i !=
s) {
Node<
Object>
next =
h.
get();
array[
i] = (T)
next.
value;
i++;
h =
next;
}
if (
array.length >
s) {
array[
s] = null;
}
}
return
array;
}
@
Override
@
SuppressWarnings("unchecked")
public void
replay(
ReplayDisposable<T>
rs) {
if (
rs.
getAndIncrement() != 0) {
return;
}
int
missed = 1;
final
Observer<? super T>
a =
rs.
downstream;
Node<
Object>
index = (
Node<
Object>)
rs.
index;
if (
index == null) {
index =
head;
}
for (;;) {
for (;;) {
if (
rs.
cancelled) {
rs.
index = null;
return;
}
Node<
Object>
n =
index.
get();
if (
n == null) {
break;
}
Object o =
n.
value;
if (
done) {
if (
n.
get() == null) {
if (
NotificationLite.
isComplete(
o)) {
a.
onComplete();
} else {
a.
onError(
NotificationLite.
getError(
o));
}
rs.
index = null;
rs.
cancelled = true;
return;
}
}
a.
onNext((T)
o);
index =
n;
}
if (
index.
get() != null) {
continue;
}
rs.
index =
index;
missed =
rs.
addAndGet(-
missed);
if (
missed == 0) {
break;
}
}
}
@
Override
public int
size() {
int
s = 0;
Node<
Object>
h =
head;
while (
s !=
Integer.
MAX_VALUE) {
Node<
Object>
next =
h.
get();
if (
next == null) {
Object o =
h.
value;
if (
NotificationLite.
isComplete(
o) ||
NotificationLite.
isError(
o)) {
s--;
}
break;
}
s++;
h =
next;
}
return
s;
}
}
static final class
SizeAndTimeBoundReplayBuffer<T>
extends
AtomicReference<
Object>
implements
ReplayBuffer<T> {
private static final long
serialVersionUID = -8056260896137901749L;
final int
maxSize;
final long
maxAge;
final
TimeUnit unit;
final
Scheduler scheduler;
int
size;
volatile
TimedNode<
Object>
head;
TimedNode<
Object>
tail;
volatile boolean
done;
SizeAndTimeBoundReplayBuffer(int
maxSize, long
maxAge,
TimeUnit unit,
Scheduler scheduler) {
this.
maxSize =
ObjectHelper.
verifyPositive(
maxSize, "maxSize");
this.
maxAge =
ObjectHelper.
verifyPositive(
maxAge, "maxAge");
this.
unit =
ObjectHelper.
requireNonNull(
unit, "unit is null");
this.
scheduler =
ObjectHelper.
requireNonNull(
scheduler, "scheduler is null");
TimedNode<
Object>
h = new
TimedNode<
Object>(null, 0L);
this.
tail =
h;
this.
head =
h;
}
void
trim() {
if (
size >
maxSize) {
size--;
TimedNode<
Object>
h =
head;
head =
h.
get();
}
long
limit =
scheduler.
now(
unit) -
maxAge;
TimedNode<
Object>
h =
head;
for (;;) {
TimedNode<
Object>
next =
h.
get();
if (
next == null) {
head =
h;
break;
}
if (
next.
time >
limit) {
head =
h;
break;
}
h =
next;
}
}
void
trimFinal() {
long
limit =
scheduler.
now(
unit) -
maxAge;
TimedNode<
Object>
h =
head;
for (;;) {
TimedNode<
Object>
next =
h.
get();
if (
next.
get() == null) {
if (
h.
value != null) {
TimedNode<
Object>
lasth = new
TimedNode<
Object>(null, 0L);
lasth.
lazySet(
h.
get());
head =
lasth;
} else {
head =
h;
}
break;
}
if (
next.
time >
limit) {
if (
h.
value != null) {
TimedNode<
Object>
lasth = new
TimedNode<
Object>(null, 0L);
lasth.
lazySet(
h.
get());
head =
lasth;
} else {
head =
h;
}
break;
}
h =
next;
}
}
@
Override
public void
add(T
value) {
TimedNode<
Object>
n = new
TimedNode<
Object>(
value,
scheduler.
now(
unit));
TimedNode<
Object>
t =
tail;
tail =
n;
size++;
t.
set(
n); // releases both the tail and size
trim();
}
@
Override
public void
addFinal(
Object notificationLite) {
TimedNode<
Object>
n = new
TimedNode<
Object>(
notificationLite,
Long.
MAX_VALUE);
TimedNode<
Object>
t =
tail;
tail =
n;
size++;
t.
lazySet(
n); // releases both the tail and size
trimFinal();
done = true;
}
/**
* Replace a non-empty head node with an empty one to
* allow the GC of the inaccessible old value.
*/
@
Override
public void
trimHead() {
TimedNode<
Object>
h =
head;
if (
h.
value != null) {
TimedNode<
Object>
n = new
TimedNode<
Object>(null, 0);
n.
lazySet(
h.
get());
head =
n;
}
}
@
Override
@
Nullable
@
SuppressWarnings("unchecked")
public T
getValue() {
TimedNode<
Object>
prev = null;
TimedNode<
Object>
h =
head;
for (;;) {
TimedNode<
Object>
next =
h.
get();
if (
next == null) {
break;
}
prev =
h;
h =
next;
}
long
limit =
scheduler.
now(
unit) -
maxAge;
if (
h.
time <
limit) {
return null;
}
Object v =
h.
value;
if (
v == null) {
return null;
}
if (
NotificationLite.
isComplete(
v) ||
NotificationLite.
isError(
v)) {
return (T)
prev.
value;
}
return (T)
v;
}
TimedNode<
Object>
getHead() {
TimedNode<
Object>
index =
head;
// skip old entries
long
limit =
scheduler.
now(
unit) -
maxAge;
TimedNode<
Object>
next =
index.
get();
while (
next != null) {
long
ts =
next.
time;
if (
ts >
limit) {
break;
}
index =
next;
next =
index.
get();
}
return
index;
}
@
Override
@
SuppressWarnings("unchecked")
public T[]
getValues(T[]
array) {
TimedNode<
Object>
h =
getHead();
int
s =
size(
h);
if (
s == 0) {
if (
array.length != 0) {
array[0] = null;
}
} else {
if (
array.length <
s) {
array = (T[])
Array.
newInstance(
array.
getClass().
getComponentType(),
s);
}
int
i = 0;
while (
i !=
s) {
TimedNode<
Object>
next =
h.
get();
array[
i] = (T)
next.
value;
i++;
h =
next;
}
if (
array.length >
s) {
array[
s] = null;
}
}
return
array;
}
@
Override
@
SuppressWarnings("unchecked")
public void
replay(
ReplayDisposable<T>
rs) {
if (
rs.
getAndIncrement() != 0) {
return;
}
int
missed = 1;
final
Observer<? super T>
a =
rs.
downstream;
TimedNode<
Object>
index = (
TimedNode<
Object>)
rs.
index;
if (
index == null) {
index =
getHead();
}
for (;;) {
if (
rs.
cancelled) {
rs.
index = null;
return;
}
for (;;) {
if (
rs.
cancelled) {
rs.
index = null;
return;
}
TimedNode<
Object>
n =
index.
get();
if (
n == null) {
break;
}
Object o =
n.
value;
if (
done) {
if (
n.
get() == null) {
if (
NotificationLite.
isComplete(
o)) {
a.
onComplete();
} else {
a.
onError(
NotificationLite.
getError(
o));
}
rs.
index = null;
rs.
cancelled = true;
return;
}
}
a.
onNext((T)
o);
index =
n;
}
if (
index.
get() != null) {
continue;
}
rs.
index =
index;
missed =
rs.
addAndGet(-
missed);
if (
missed == 0) {
break;
}
}
}
@
Override
public int
size() {
return
size(
getHead());
}
int
size(
TimedNode<
Object>
h) {
int
s = 0;
while (
s !=
Integer.
MAX_VALUE) {
TimedNode<
Object>
next =
h.
get();
if (
next == null) {
Object o =
h.
value;
if (
NotificationLite.
isComplete(
o) ||
NotificationLite.
isError(
o)) {
s--;
}
break;
}
s++;
h =
next;
}
return
s;
}
}
}