org.tools4j.nobark.queue

Interface ExchangeConflationQueue<K,V>

Type Parameters:

K - the type of the conflation key

V - the type of values in the queue

All Superinterfaces:

ConflationQueue<K,V>

All Known Implementing Classes:

EvictConflationQueue, MergeConflationQueue

public interface ExchangeConflationQueue<K,V>
extends ConflationQueue<K,V>

A conflation queue variant that allows exchanging of elements between the consumer and the producer. Naturally the producer already sends values to the consumer; with an exchange queue the consumer can pass values back to the producer when polling values. This can for instance be used to reduce garbage by circulating and reusing values between producer and consumer.

Nested Class Summary

Nested Classes

Modifier and Type	Interface and Description
static interface	ExchangeConflationQueue.ExchangePoller<K,V> Poller object used by the consumer to poll values; exchange poller adds functionality for exchanging values with the producer during poll operations.

Nested classes/interfaces inherited from interface org.tools4j.nobark.queue.ConflationQueue

ConflationQueue.Appender<K,V>, ConflationQueue.Poller<K,V>

Method Summary

Modifier and Type	Method and Description
ConflationQueue.Appender<K,V>	appender() Returns the appender object used by the producer to enqueue values.
static <K,V> ConflationQueue.Appender<K,V>	nullSafe(ConflationQueue.Appender<K,V> unsafeAppender, java.util.function.Function<? super K,? extends V> valueFactory) Returns an Appender whose enqueue(..) method is guaranteed to never return null.
static <K,V> ExchangeConflationQueue<K,V>	nullSafe(ExchangeConflationQueue<K,V> unsafeQueue, java.util.function.Function<? super K,? extends V> valueFactory) Returns an ExchangeConflationQueue whose appender is guaranteed to never return null on enqueue.
ExchangeConflationQueue.ExchangePoller<K,V>	poller() Returns the poller object used by the consumer to poll values.

Methods inherited from interface org.tools4j.nobark.queue.ConflationQueue

size

Method Detail

appender

ConflationQueue.Appender<K,V> appender()

Description copied from interface: ConflationQueue

Returns the appender object used by the producer to enqueue values. Some conflation queue implementations return thread-safe appender instances, other implementations return an instance per caller thread. Hence it is highly recommended to access the appender via this method directly from the producer thread and not share it between threads.

Specified by:

appender in interface ConflationQueue<K,V>

Returns:

the appender object used to enqueue values

poller

ExchangeConflationQueue.ExchangePoller<K,V> poller()

Description copied from interface: ConflationQueue

Returns the poller object used by the consumer to poll values. Some conflation queue implementations return thread-safe poller instances, other implementations return an instance per caller thread. Hence it is highly recommended to access the poller via this method directly from the consumer thread and not share it between threads.

Specified by:

poller in interface ConflationQueue<K,V>

Returns:

the poller object used to poll values

nullSafe

static <K,V> ExchangeConflationQueue<K,V> nullSafe(ExchangeConflationQueue<K,V> unsafeQueue,
                                                   java.util.function.Function<? super K,? extends V> valueFactory)

Returns an ExchangeConflationQueue whose appender is guaranteed to never return null on enqueue. If the unsafe queue returns null on enqueue e.g. because the queue is empty and no exchange values can be retrieved yet, the specified cqFactory is used to create a value.

Type Parameters:

K - the type of the conflation key

V - the type of values in the queue

Parameters:

unsafeQueue - the unsafe queue possibly returning null values on enqueue

valueFactory - the value cqFactory used if the unsafe queue returned null when a value was enqueued

Returns:

a null-safe version of the queue that never returns null values when enqueuing values

nullSafe

static <K,V> ConflationQueue.Appender<K,V> nullSafe(ConflationQueue.Appender<K,V> unsafeAppender,
                                                    java.util.function.Function<? super K,? extends V> valueFactory)

Returns an Appender whose enqueue(..) method is guaranteed to never return null. If the unsafe appender returns null on enqueue e.g. because the queue is empty and no exchange values can be retrieved yet, the specified cqFactory is used to create a value.

Type Parameters:

K - the type of the conflation key

V - the type of values in the queue

Parameters:

unsafeAppender - the unsafe appender possibly returning null values on enqueue

valueFactory - the value cqFactory used if the unsafe enqueuing operation returned null

Returns:

a null-safe version of the appender that never returns null values when enqueuing values