Package com.lmax.disruptor

Class EventPoller<T>

java.lang.Object

com.lmax.disruptor.EventPoller<T>

Type Parameters:

T - the type of event used.

public class EventPoller<T>
extends Object

Experimental poll-based interface for the Disruptor. Unlike a BatchEventProcessor, an event poller allows the user to control the flow of execution. This makes it ideal for interoperability with existing threads whose lifecycle is not controlled by the disruptor DSL.

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
static interface	EventPoller.Handler<T>	A callback used to process events
static enum	EventPoller.PollState	Indicates the result of a call to poll(Handler)

Field Summary

Fields

Modifier and Type	Field	Description
private final DataProvider<T>	dataProvider
private final Sequence	gatingSequence
private final Sequence	sequence
private final Sequencer	sequencer

Constructor Summary

Constructors

Constructor	Description
EventPoller(DataProvider<T> dataProvider, Sequencer sequencer, Sequence sequence, Sequence gatingSequence)	Creates an event poller.

Method Summary

Modifier and Type	Method	Description
Sequence	getSequence()	Get the Sequence being used by this event poller
static <T> EventPoller<T>	newInstance(DataProvider<T> dataProvider, Sequencer sequencer, Sequence sequence, Sequence cursorSequence, Sequence... gatingSequences)	Creates an event poller.
EventPoller.PollState	poll(EventPoller.Handler<T> eventHandler)	Polls for events using the given handler.

Methods inherited from class java.lang.Object

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

Field Details

dataProvider

private final DataProvider<T> dataProvider

sequencer

private final Sequencer sequencer

sequence

private final Sequence sequence

gatingSequence

private final Sequence gatingSequence

Constructor Details

EventPoller

public EventPoller(DataProvider<T> dataProvider,
 Sequencer sequencer,
 Sequence sequence,
 Sequence gatingSequence)

Creates an event poller. Most users will want RingBuffer.newPoller(Sequence...) which will set up the poller automatically

Parameters:

dataProvider - from which events are drawn

sequencer - the main sequencer which handles ordering of events

sequence - the sequence which will be used by this event poller

gatingSequence - the sequences to gate on

Method Details

poll

public EventPoller.PollState poll(EventPoller.Handler<T> eventHandler)
                           throws Exception

Polls for events using the given handler.

This poller will continue to feed events to the given handler until known available events are consumed or EventPoller.Handler.onEvent(Object, long, boolean) returns false.

Note that it is possible for more events to become available while the current events are being processed. A further call to this method will process such events.

Parameters:

eventHandler - the handler used to consume events

Returns:

the state of the event poller after the poll is attempted

Throws:

Exception - exceptions thrown from the event handler are propagated to the caller

newInstance

public static <T> EventPoller<T> newInstance(DataProvider<T> dataProvider,
 Sequencer sequencer,
 Sequence sequence,
 Sequence cursorSequence,
 Sequence... gatingSequences)

Creates an event poller. Most users will want RingBuffer.newPoller(Sequence...) which will set up the poller automatically

Type Parameters:

T - the type of the event

Parameters:

dataProvider - from which events are drawn

sequencer - the main sequencer which handles ordering of events

sequence - the sequence which will be used by this event poller

cursorSequence - the cursor sequence, usually of the ring buffer

gatingSequences - additional sequences to gate on

Returns:

the event poller

getSequence

public Sequence getSequence()

Get the Sequence being used by this event poller

Returns:

the sequence used by the event poller