See: Description
Interface | Description |
---|---|
Cursored |
Implementors of this interface must provide a single long value
that represents their current cursor value.
|
DataProvider<T> | |
EventFactory<T> |
Called by the
RingBuffer to pre-populate all the events to fill the RingBuffer. |
EventHandler<T> |
Callback interface to be implemented for processing events as they become available in the
RingBuffer |
EventProcessor |
EventProcessors waitFor events to become available for consumption from the
RingBuffer
An EventProcessor will generally be associated with a Thread for execution. |
EventTranslator<T> |
Implementations translate (write) data representations into events claimed from the
RingBuffer .
When publishing to the RingBuffer, provide an EventTranslator. |
EventTranslatorOneArg<T,A> |
Implementations translate another data representations into events claimed from the
RingBuffer |
EventTranslatorThreeArg<T,A,B,C> |
Implementations translate another data representations into events claimed from the
RingBuffer |
EventTranslatorTwoArg<T,A,B> |
Implementations translate another data representations into events claimed from the
RingBuffer |
EventTranslatorVararg<T> |
Implementations translate another data representations into events claimed from the
RingBuffer |
ExceptionHandler |
Callback handler for uncaught exceptions in the event processing cycle of the
BatchEventProcessor |
LifecycleAware |
Implement this interface in your
EventHandler to be notified when a thread for the
BatchEventProcessor starts and shuts down. |
SequenceBarrier |
Coordination barrier for tracking the cursor for publishers and sequence of
dependent
EventProcessor s for processing a data structure |
Sequencer |
Coordinates claiming sequences for access to a data structure while tracking dependent
Sequence s |
SequenceReportingEventHandler<T> |
Used by the
BatchEventProcessor to set a callback allowing the EventHandler to notify
when it has finished consuming an event if this happens after the EventHandler.onEvent(Object, long, boolean) call. |
TimeoutHandler | |
WaitStrategy |
Strategy employed for making
EventProcessor s wait on a cursor Sequence . |
WorkHandler<T> |
Callback interface to be implemented for processing units of work as they become available in the
RingBuffer . |
Class | Description |
---|---|
AbstractSequencer |
Base class for the various sequencer types (single/multi).
|
AggregateEventHandler<T> |
An aggregate collection of
EventHandler s that get called in sequence for each event. |
BatchEventProcessor<T> |
Convenience class for handling the batching semantics of consuming entries from a
RingBuffer
and delegating the available events to an EventHandler . |
BlockingWaitStrategy |
Blocking strategy that uses a lock and condition variable for
EventProcessor s waiting on a barrier. |
BusySpinWaitStrategy |
Busy Spin strategy that uses a busy spin loop for
EventProcessor s waiting on a barrier. |
FatalExceptionHandler |
Convenience implementation of an exception handler that using standard JDK logging to log
the exception as
Level .SEVERE and re-throw it wrapped in a RuntimeException |
FixedSequenceGroup |
Hides a group of Sequences behind a single Sequence
|
IgnoreExceptionHandler |
Convenience implementation of an exception handler that using standard JDK logging to log
the exception as
Level .INFO |
MultiProducerSequencer |
Coordinator for claiming sequences for access to a data structure while tracking dependent
Sequence s
Suitable for use for sequencing across multiple publisher threads. |
NoOpEventProcessor |
No operation version of a
EventProcessor that simply tracks a Sequence . |
PhasedBackoffWaitStrategy |
Phased wait strategy for waiting
EventProcessor s on a barrier.
This strategy can be used when throughput and low-latency are not as important as CPU resource.
Spins, then yields, then blocks on the configured BlockingStrategy. |
RingBuffer<E> |
Ring based store of reusable entries containing the data representing
an event being exchanged between event producer and
EventProcessor s. |
Sequence |
Concurrent sequence class used for tracking the progress of
the ring buffer and event processors.
|
SequenceGroup | |
SingleProducerSequencer |
Coordinator for claiming sequences for access to a data structure while tracking dependent
Sequence s.
Generally not safe for use from multiple threads as it does not implement any barriers. |
SleepingWaitStrategy |
Sleeping strategy that initially spins, then uses a Thread.yield(), and eventually for the minimum number of nanos
the OS and JVM will allow while the
EventProcessor s are waiting on a barrier. |
TimeoutBlockingWaitStrategy | |
WorkerPool<T> |
WorkerPool contains a pool of
WorkProcessor s that will consume sequences so jobs can be farmed out across a pool of workers. |
WorkProcessor<T> |
A
WorkProcessor wraps a single WorkHandler , effectively consuming the sequence
and ensuring appropriate barriers.
Generally, this will be used as part of a WorkerPool . |
YieldingWaitStrategy |
Yielding strategy that uses a Thread.yield() for
EventProcessor s waiting on a barrier
after an initially spinning. |
Exception | Description |
---|---|
AlertException |
Used to alert
EventProcessor s waiting at a SequenceBarrier of status changes. |
InsufficientCapacityException |
Exception thrown when the it is not possible to insert a value into
the ring buffer without it wrapping the consuming sequenes.
|
The Disruptor is a concurrent programming framework for exchanging and coordinating work as a continuous series of events. It can be used as an alternative to wiring processing stages together via queues. The Disruptor design has the characteristics of generating significantly less garbage than queues and separates the concurrency concerns so non-locking algorithms can be employed resulting in greater scalability and performance.
It works on the principle of having a number of stages that are each single threaded with local state and memory. No global memory exists and all communication is achieved by passing messages/state via managed ring buffers.
Almost any graph or pipeline structure can be composed via one or more Disruptor patterns.
UniCast a series of items between 1 publisher and 1 EventProcessor.
track to prevent wrap +------------------+ | | | v +----+ +-----+ +----+ +====+ +====+ +-----+ | P1 |--->| EP1 | | P1 |--->| RB |<---| SB | | EP1 | +----+ +-----+ +----+ +====+ +====+ +-----+ claim get ^ | | | +--------+ waitFor
Sequence a series of messages from multiple publishers
track to prevent wrap +--------------------+ | | | v +----+ +----+ +====+ +====+ +-----+ | P1 |-------+ | P1 |--->| RB |<---| SB | | EP1 | +----+ | +----+ +====+ +====+ +-----+ v ^ get ^ | +----+ +-----+ +----+ | | | | P2 |--->| EP1 | | P2 |------+ +---------+ +----+ +-----+ +----+ | waitFor ^ | +----+ | +----+ | | P3 |-------+ | P3 |------+ +----+ +----+
Pipeline a series of messages
+----+ +-----+ +-----+ +-----+ | P1 |--->| EP1 |--->| EP2 |--->| EP3 | +----+ +-----+ +-----+ +-----+ track to prevent wrap +----------------------------------------------------------------+ | | | v +----+ +====+ +=====+ +-----+ +=====+ +-----+ +=====+ +-----+ | P1 |--->| RB | | SB1 |<---| EP1 |<---| SB2 |<---| EP2 |<---| SB3 |<---| EP3 | +----+ +====+ +=====+ +-----+ +=====+ +-----+ +=====+ +-----+ claim ^ get | waitFor | waitFor | waitFor | | | | +---------+---------------------+---------------------+
Multicast a series of messages to multiple EventProcessors
+-----+ track to prevent wrap +----->| EP1 | +--------------------+----------+----------+ | +-----+ | | | | | | v v v +----+ +-----+ +----+ +====+ +====+ +-----+ +-----+ +-----+ | P1 |--->| EP2 | | P1 |--->| RB |<---| SB | | EP1 | | EP2 | | EP3 | +----+ +-----+ +----+ +====+ +====+ +-----+ +-----+ +-----+ | claim get ^ | | | | +-----+ | | | | +----->| EP3 | +---------+----------+----------+ +-----+ waitFor
Replicate a message then fold back the results
+-----+ track to prevent wrap +----->| EP1 |-----+ +-------------------------------+ | +-----+ | | | | v | v +----+ +-----+ +----+ +====+ +=====+ +-----+ | P1 | | EP3 | | P1 |--->| RB |<--------------| SB2 |<---| EP3 | +----+ +-----+ +----+ +====+ +=====+ +-----+ | ^ claim ^ get | waitFor | +-----+ | | | +----->| EP2 |-----+ +=====+ +-----+ | +-----+ | SB1 |<---| EP1 |<-----+ +=====+ +-----+ | ^ | | +-----+ | +-------| EP2 |<-----+ waitFor +-----+
// Event holder for data to be exchanged public final class ValueEvent { private long value; public long getValue() { return value; } public void setValue(final long value) { this.value = value; } public final static EventFactory<ValueEvent> EVENT_FACTORY = new EventFactory<ValueEvent>() { public ValueEvent newInstance() { return new ValueEvent(); } }; } // Callback handler which can be implemented by EventProcessors final EventHandler<ValueEvent> eventHandler = new EventHandler<ValueEvent>() { public void onEvent(final ValueEvent event, final long sequence, final boolean endOfBatch) throws Exception { // process a new event as it becomes available. } }; RingBuffer<ValueEvent> ringBuffer = new RingBuffer<ValueEvent>(ValueEvent.EVENT_FACTORY, new SingleThreadedClaimStrategy(BUFFER_SIZE), new SleepingWaitStrategy()); SequenceBarrier<ValueEvent> sequenceBarrier = ringBuffer.newBarrier(); BatchEventProcessor<ValueEvent> batchProcessor = new BatchEventProcessor<ValueEvent>(sequenceBarrier, eventHandler); ringBuffer.setGatingSequences(batchProcessor.getSequence()); // Each processor runs on a separate thread EXECUTOR.submit(batchProcessor); // Publishers claim events in sequence long sequence = ringBuffer.next(); ValueEvent event = ringBuffer.get(sequence); event.setValue(1234); // publish the event so it is available to EventProcessors ringBuffer.publish(sequence);
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