com.lmax.disruptor.dsl

Class Disruptor<T>

java.lang.Object

com.lmax.disruptor.dsl.Disruptor<T>

Type Parameters:

T - the type of event used.

public class Disruptor<T>
extends java.lang.Object

A DSL-style API for setting up the disruptor pattern around a ring buffer (aka the Builder pattern).

A simple example of setting up the disruptor with two event handlers that must process events in order:

 Disruptor<MyEvent> disruptor = new Disruptor<MyEvent>(MyEvent.FACTORY, 32, Executors.newCachedThreadPool());
 EventHandler<MyEvent> handler1 = new EventHandler<MyEvent>() { ... };
 EventHandler<MyEvent> handler2 = new EventHandler<MyEvent>() { ... };
 disruptor.handleEventsWith(handler1);
 disruptor.after(handler1).handleEventsWith(handler2);

 RingBuffer ringBuffer = disruptor.start();
 

Constructor Summary

Constructors

Constructor and Description
Disruptor(EventFactory<T> eventFactory, int ringBufferSize, java.util.concurrent.Executor executor) Deprecated. Use a ThreadFactory instead of an Executor as a the ThreadFactory is able to report errors when it is unable to construct a thread to run a producer.
Disruptor(EventFactory<T> eventFactory, int ringBufferSize, java.util.concurrent.Executor executor, ProducerType producerType, WaitStrategy waitStrategy) Deprecated. Use a ThreadFactory instead of an Executor as a the ThreadFactory is able to report errors when it is unable to construct a thread to run a producer.
Disruptor(EventFactory<T> eventFactory, int ringBufferSize, java.util.concurrent.ThreadFactory threadFactory) Create a new Disruptor.
Disruptor(EventFactory<T> eventFactory, int ringBufferSize, java.util.concurrent.ThreadFactory threadFactory, ProducerType producerType, WaitStrategy waitStrategy) Create a new Disruptor.

Method Summary

Modifier and Type	Method and Description
EventHandlerGroup<T>	after(EventHandler<T>... handlers) Create a group of event handlers to be used as a dependency.
EventHandlerGroup<T>	after(EventProcessor... processors) Create a group of event processors to be used as a dependency.
T	get(long sequence) Get the event for a given sequence in the RingBuffer.
SequenceBarrier	getBarrierFor(EventHandler<T> handler) Get the SequenceBarrier used by a specific handler.
long	getBufferSize() The capacity of the data structure to hold entries.
long	getCursor() Get the value of the cursor indicating the published sequence.
RingBuffer<T>	getRingBuffer() The RingBuffer used by this Disruptor.
long	getSequenceValueFor(EventHandler<T> b1) Gets the sequence value for the specified event handlers.
void	halt() Calls EventProcessor.halt() on all of the event processors created via this disruptor.
EventHandlerGroup<T>	handleEventsWith(EventHandler<? super T>... handlers) Set up event handlers to handle events from the ring buffer.
EventHandlerGroup<T>	handleEventsWith(EventProcessor... processors) Set up custom event processors to handle events from the ring buffer.
EventHandlerGroup<T>	handleEventsWith(EventProcessorFactory<T>... eventProcessorFactories) Set up custom event processors to handle events from the ring buffer.
EventHandlerGroup<T>	handleEventsWithWorkerPool(WorkHandler<T>... workHandlers) Set up a WorkerPool to distribute an event to one of a pool of work handler threads.
ExceptionHandlerSetting<T>	handleExceptionsFor(EventHandler<T> eventHandler) Override the default exception handler for a specific handler.
void	handleExceptionsWith(ExceptionHandler<? super T> exceptionHandler) Deprecated. This method only applies to future event handlers. Use setDefaultExceptionHandler instead which applies to existing and new event handlers.
void	publishEvent(EventTranslator<T> eventTranslator) Publish an event to the ring buffer.
<A> void	publishEvent(EventTranslatorOneArg<T,A> eventTranslator, A arg) Publish an event to the ring buffer.
<A,B,C> void	publishEvent(EventTranslatorThreeArg<T,A,B,C> eventTranslator, A arg0, B arg1, C arg2) Publish an event to the ring buffer.
<A,B> void	publishEvent(EventTranslatorTwoArg<T,A,B> eventTranslator, A arg0, B arg1) Publish an event to the ring buffer.
<A> void	publishEvents(EventTranslatorOneArg<T,A> eventTranslator, A[] arg) Publish a batch of events to the ring buffer.
void	setDefaultExceptionHandler(ExceptionHandler<? super T> exceptionHandler) Specify an exception handler to be used for event handlers and worker pools created by this Disruptor.
void	shutdown() Waits until all events currently in the disruptor have been processed by all event processors and then halts the processors.
void	shutdown(long timeout, java.util.concurrent.TimeUnit timeUnit) Waits until all events currently in the disruptor have been processed by all event processors and then halts the processors.
RingBuffer<T>	start() Starts the event processors and returns the fully configured ring buffer.
java.lang.String	toString()

Methods inherited from class java.lang.Object

equals, getClass, hashCode, notify, notifyAll, wait, wait, wait

Constructor Detail

Disruptor

@Deprecated
public Disruptor(EventFactory<T> eventFactory,
                             int ringBufferSize,
                             java.util.concurrent.Executor executor)

Deprecated. Use a ThreadFactory instead of an Executor as a the ThreadFactory is able to report errors when it is unable to construct a thread to run a producer.

Create a new Disruptor. Will default to BlockingWaitStrategy and ProducerType.MULTI

Parameters:

eventFactory - the factory to create events in the ring buffer.

ringBufferSize - the size of the ring buffer.

executor - an Executor to execute event processors.

Disruptor

@Deprecated
public Disruptor(EventFactory<T> eventFactory,
                             int ringBufferSize,
                             java.util.concurrent.Executor executor,
                             ProducerType producerType,
                             WaitStrategy waitStrategy)

Deprecated. Use a ThreadFactory instead of an Executor as a the ThreadFactory is able to report errors when it is unable to construct a thread to run a producer.

Create a new Disruptor.

Parameters:

eventFactory - the factory to create events in the ring buffer.

ringBufferSize - the size of the ring buffer, must be power of 2.

executor - an Executor to execute event processors.

producerType - the claim strategy to use for the ring buffer.

waitStrategy - the wait strategy to use for the ring buffer.

Disruptor

public Disruptor(EventFactory<T> eventFactory,
                 int ringBufferSize,
                 java.util.concurrent.ThreadFactory threadFactory)

Create a new Disruptor. Will default to BlockingWaitStrategy and ProducerType.MULTI

Parameters:

eventFactory - the factory to create events in the ring buffer.

ringBufferSize - the size of the ring buffer.

threadFactory - a ThreadFactory to create threads to for processors.

Disruptor

public Disruptor(EventFactory<T> eventFactory,
                 int ringBufferSize,
                 java.util.concurrent.ThreadFactory threadFactory,
                 ProducerType producerType,
                 WaitStrategy waitStrategy)

Create a new Disruptor.

Parameters:

eventFactory - the factory to create events in the ring buffer.

ringBufferSize - the size of the ring buffer, must be power of 2.

threadFactory - a ThreadFactory to create threads for processors.

producerType - the claim strategy to use for the ring buffer.

waitStrategy - the wait strategy to use for the ring buffer.

Method Detail

handleEventsWith

@SafeVarargs
public final EventHandlerGroup<T> handleEventsWith(EventHandler<? super T>... handlers)

Set up event handlers to handle events from the ring buffer. These handlers will process events as soon as they become available, in parallel.

This method can be used as the start of a chain. For example if the handler A must process events before handler B:

dw.handleEventsWith(A).then(B);

This call is additive, but generally should only be called once when setting up the Disruptor instance

Parameters:

handlers - the event handlers that will process events.

Returns:

a EventHandlerGroup that can be used to chain dependencies.

handleEventsWith

@SafeVarargs
public final EventHandlerGroup<T> handleEventsWith(EventProcessorFactory<T>... eventProcessorFactories)

Set up custom event processors to handle events from the ring buffer. The Disruptor will automatically start these processors when start() is called.

This method can be used as the start of a chain. For example if the handler A must process events before handler B:

dw.handleEventsWith(A).then(B);

Since this is the start of the chain, the processor factories will always be passed an empty Sequence array, so the factory isn't necessary in this case. This method is provided for consistency with EventHandlerGroup.handleEventsWith(EventProcessorFactory...) and EventHandlerGroup.then(EventProcessorFactory...) which do have barrier sequences to provide.

This call is additive, but generally should only be called once when setting up the Disruptor instance

Parameters:

eventProcessorFactories - the event processor factories to use to create the event processors that will process events.

Returns:

a EventHandlerGroup that can be used to chain dependencies.

handleEventsWith

public EventHandlerGroup<T> handleEventsWith(EventProcessor... processors)

Set up custom event processors to handle events from the ring buffer. The Disruptor will automatically start this processors when start() is called.

This method can be used as the start of a chain. For example if the processor A must process events before handler B:

dw.handleEventsWith(A).then(B);

Parameters:

processors - the event processors that will process events.

Returns:

a EventHandlerGroup that can be used to chain dependencies.

handleEventsWithWorkerPool

@SafeVarargs
public final EventHandlerGroup<T> handleEventsWithWorkerPool(WorkHandler<T>... workHandlers)

Set up a WorkerPool to distribute an event to one of a pool of work handler threads. Each event will only be processed by one of the work handlers. The Disruptor will automatically start this processors when start() is called.

Parameters:

workHandlers - the work handlers that will process events.

Returns:

a EventHandlerGroup that can be used to chain dependencies.

handleExceptionsWith

public void handleExceptionsWith(ExceptionHandler<? super T> exceptionHandler)

Deprecated. This method only applies to future event handlers. Use setDefaultExceptionHandler instead which applies to existing and new event handlers.

Specify an exception handler to be used for any future event handlers.

Note that only event handlers set up after calling this method will use the exception handler.

Parameters:

exceptionHandler - the exception handler to use for any future EventProcessor.

setDefaultExceptionHandler

public void setDefaultExceptionHandler(ExceptionHandler<? super T> exceptionHandler)

Specify an exception handler to be used for event handlers and worker pools created by this Disruptor.

The exception handler will be used by existing and future event handlers and worker pools created by this Disruptor instance.

Parameters:

exceptionHandler - the exception handler to use.

handleExceptionsFor

public ExceptionHandlerSetting<T> handleExceptionsFor(EventHandler<T> eventHandler)

Override the default exception handler for a specific handler.

disruptorWizard.handleExceptionsIn(eventHandler).with(exceptionHandler);

Parameters:

eventHandler - the event handler to set a different exception handler for.

Returns:

an ExceptionHandlerSetting dsl object - intended to be used by chaining the with method call.

after

@SafeVarargs
public final EventHandlerGroup<T> after(EventHandler<T>... handlers)

Create a group of event handlers to be used as a dependency. For example if the handler A must process events before handler B:

dw.after(A).handleEventsWith(B);

Parameters:

handlers - the event handlers, previously set up with handleEventsWith(com.lmax.disruptor.EventHandler[]), that will form the barrier for subsequent handlers or processors.

Returns:

an EventHandlerGroup that can be used to setup a dependency barrier over the specified event handlers.

after

public EventHandlerGroup<T> after(EventProcessor... processors)

Create a group of event processors to be used as a dependency.

Parameters:

processors - the event processors, previously set up with handleEventsWith(com.lmax.disruptor.EventProcessor...), that will form the barrier for subsequent handlers or processors.

Returns:

an EventHandlerGroup that can be used to setup a SequenceBarrier over the specified event processors.

See Also:

after(com.lmax.disruptor.EventHandler[])

publishEvent

public void publishEvent(EventTranslator<T> eventTranslator)

Publish an event to the ring buffer.

Parameters:

eventTranslator - the translator that will load data into the event.

publishEvent

public <A> void publishEvent(EventTranslatorOneArg<T,A> eventTranslator,
                             A arg)

Publish an event to the ring buffer.

Type Parameters:

A - Class of the user supplied argument.

Parameters:

eventTranslator - the translator that will load data into the event.

arg - A single argument to load into the event

publishEvents

public <A> void publishEvents(EventTranslatorOneArg<T,A> eventTranslator,
                              A[] arg)

Publish a batch of events to the ring buffer.

Type Parameters:

A - Class of the user supplied argument.

Parameters:

eventTranslator - the translator that will load data into the event.

arg - An array single arguments to load into the events. One Per event.

publishEvent

public <A,B> void publishEvent(EventTranslatorTwoArg<T,A,B> eventTranslator,
                               A arg0,
                               B arg1)

Publish an event to the ring buffer.

Type Parameters:

A - Class of the user supplied argument.

B - Class of the user supplied argument.

Parameters:

eventTranslator - the translator that will load data into the event.

arg0 - The first argument to load into the event

arg1 - The second argument to load into the event

publishEvent

public <A,B,C> void publishEvent(EventTranslatorThreeArg<T,A,B,C> eventTranslator,
                                 A arg0,
                                 B arg1,
                                 C arg2)

Publish an event to the ring buffer.

Type Parameters:

A - Class of the user supplied argument.

B - Class of the user supplied argument.

C - Class of the user supplied argument.

Parameters:

eventTranslator - the translator that will load data into the event.

arg0 - The first argument to load into the event

arg1 - The second argument to load into the event

arg2 - The third argument to load into the event

start

public RingBuffer<T> start()

Starts the event processors and returns the fully configured ring buffer.

The ring buffer is set up to prevent overwriting any entry that is yet to be processed by the slowest event processor.

This method must only be called once after all event processors have been added.

Returns:

the configured ring buffer.

halt

public void halt()

Calls EventProcessor.halt() on all of the event processors created via this disruptor.

shutdown

public void shutdown()

Waits until all events currently in the disruptor have been processed by all event processors and then halts the processors. It is critical that publishing to the ring buffer has stopped before calling this method, otherwise it may never return.

This method will not shutdown the executor, nor will it await the final termination of the processor threads.

shutdown

public void shutdown(long timeout,
                     java.util.concurrent.TimeUnit timeUnit)
              throws TimeoutException

Waits until all events currently in the disruptor have been processed by all event processors and then halts the processors.

This method will not shutdown the executor, nor will it await the final termination of the processor threads.

Parameters:

timeout - the amount of time to wait for all events to be processed. -1 will give an infinite timeout

timeUnit - the unit the timeOut is specified in

Throws:

TimeoutException - if a timeout occurs before shutdown completes.

getRingBuffer

public RingBuffer<T> getRingBuffer()

The RingBuffer used by this Disruptor. This is useful for creating custom event processors if the behaviour of BatchEventProcessor is not suitable.

Returns:

the ring buffer used by this Disruptor.

getCursor

public long getCursor()

Get the value of the cursor indicating the published sequence.

Returns:

value of the cursor for events that have been published.

getBufferSize

public long getBufferSize()

The capacity of the data structure to hold entries.

Returns:

the size of the RingBuffer.

See Also:

Sequenced.getBufferSize()

get

public T get(long sequence)

Get the event for a given sequence in the RingBuffer.

Parameters:

sequence - for the event.

Returns:

event for the sequence.

See Also:

RingBuffer.get(long)

getBarrierFor

public SequenceBarrier getBarrierFor(EventHandler<T> handler)

Get the SequenceBarrier used by a specific handler. Note that the SequenceBarrier may be shared by multiple event handlers.

Parameters:

handler - the handler to get the barrier for.

Returns:

the SequenceBarrier used by handler.

getSequenceValueFor

public long getSequenceValueFor(EventHandler<T> b1)

Gets the sequence value for the specified event handlers.

Parameters:

b1 - eventHandler to get the sequence for.

Returns:

eventHandler's sequence

toString

public java.lang.String toString()

Overrides:

toString in class java.lang.Object