Package rx.internal.util

Class IndexedRingBuffer<E>

java.lang.Object

rx.internal.util.IndexedRingBuffer<E>

Type Parameters:

E -

All Implemented Interfaces:

Subscription

public final class IndexedRingBuffer<E>
extends Object
implements Subscription

Add/Remove without object allocation (after initial construction).

This is meant for hundreds or single-digit thousands of elements that need to be rapidly added and randomly or sequentially removed while avoiding object allocation.

On Intel Core i7, 2.3Mhz, Mac Java 8:

- adds per second single-threaded => ~32,598,500 for 100 - adds per second single-threaded => ~23,200,000 for 10,000 - adds + removes per second single-threaded => 15,562,100 for 100 - adds + removes per second single-threaded => 8,760,000 for 10,000

 
 Benchmark                                              (size)   Mode   Samples        Score  Score error    Units
 r.i.IndexedRingBufferPerf.indexedRingBufferAdd            100  thrpt         5   263571.721     9856.994    ops/s
 r.i.IndexedRingBufferPerf.indexedRingBufferAdd          10000  thrpt         5     1763.417      211.998    ops/s
 r.i.IndexedRingBufferPerf.indexedRingBufferAddRemove      100  thrpt         5   139850.115    17143.705    ops/s
 r.i.IndexedRingBufferPerf.indexedRingBufferAddRemove    10000  thrpt         5      809.982       72.931    ops/s
  

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
(package private) static final class	IndexedRingBuffer.ElementSection<E>
(package private) static class	IndexedRingBuffer.IndexSection

Field Summary

Fields

Modifier and Type	Field	Description
(package private) static int	defaultSize
private final IndexedRingBuffer.ElementSection<E>	elements
(package private) final AtomicInteger	index
private static final ObjectPool<IndexedRingBuffer<?>>	POOL
private final IndexedRingBuffer.IndexSection	removed
(package private) final AtomicInteger	removedIndex
(package private) static final int	SIZE

Constructor Summary

Constructors

Constructor	Description
IndexedRingBuffer()

Method Summary

Modifier and Type	Method	Description
int	add(E e)	Add an element and return the index where it was added to allow removal.
int	forEach(Func1<? super E,Boolean> action)
int	forEach(Func1<? super E,Boolean> action, int startIndex)	Loop through each element in the buffer and call a specific function.
private int	forEach(Func1<? super E,Boolean> action, int startIndex, int endIndex)
private IndexedRingBuffer.ElementSection<E>	getElementSection(int index)
private int	getIndexForAdd()
private int	getIndexFromPreviouslyRemoved()	Returns -1 if nothing, 0 or greater if the index should be used
private IndexedRingBuffer.IndexSection	getIndexSection(int index)
static <T> IndexedRingBuffer<T>	getInstance()
boolean	isUnsubscribed()	Indicates whether this Subscription is currently unsubscribed.
private void	pushRemovedIndex(int elementIndex)
void	releaseToPool()	This resets the arrays, nulls out references and returns it to the pool.
E	remove(int index)
void	unsubscribe()	Stops the receipt of notifications on the Subscriber that was registered when this Subscription was received.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Details

elements

private final IndexedRingBuffer.ElementSection<E> elements

removed

private final IndexedRingBuffer.IndexSection removed

index

final AtomicInteger index

removedIndex

final AtomicInteger removedIndex

POOL

private static final ObjectPool<IndexedRingBuffer<?>> POOL

defaultSize

static int defaultSize

SIZE

static final int SIZE

Constructor Details

IndexedRingBuffer

IndexedRingBuffer()

Method Details

getInstance

public static <T> IndexedRingBuffer<T> getInstance()

releaseToPool

public void releaseToPool()

This resets the arrays, nulls out references and returns it to the pool. This extra CPU cost is far smaller than the object allocation cost of not pooling.

unsubscribe

public void unsubscribe()

Description copied from interface: Subscription

Stops the receipt of notifications on the Subscriber that was registered when this Subscription was received.

This allows unregistering an Subscriber before it has finished receiving all events (i.e. before onCompleted is called).

Specified by:

unsubscribe in interface Subscription

add

public int add(E e)

Add an element and return the index where it was added to allow removal.

Parameters:

e - the element to add

Returns:

the index where the element was added

remove

public E remove(int index)

getIndexSection

private IndexedRingBuffer.IndexSection getIndexSection(int index)

getElementSection

private IndexedRingBuffer.ElementSection<E> getElementSection(int index)

getIndexForAdd

private int getIndexForAdd()

getIndexFromPreviouslyRemoved

private int getIndexFromPreviouslyRemoved()

Returns -1 if nothing, 0 or greater if the index should be used

Returns:

pushRemovedIndex

private void pushRemovedIndex(int elementIndex)

isUnsubscribed

public boolean isUnsubscribed()

Description copied from interface: Subscription

Indicates whether this Subscription is currently unsubscribed.

Specified by:

isUnsubscribed in interface Subscription

Returns:

true if this Subscription is currently unsubscribed, false otherwise

forEach

public int forEach(Func1<? super E,Boolean> action)

forEach

public int forEach(Func1<? super E,Boolean> action,
 int startIndex)

Loop through each element in the buffer and call a specific function.

Parameters:

action - that processes each item and returns true if it wants to continue to the next

startIndex - at which index the loop should start

Returns:

int of next index to process, or last index seen if it exited early

forEach

private int forEach(Func1<? super E,Boolean> action,
 int startIndex,
 int endIndex)