Package io.aeron.driver

Class RetransmitHandler

java.lang.Object

io.aeron.driver.RetransmitHandler

public final class RetransmitHandler
extends Object

Tracking and handling of retransmit request, NAKs, for senders, and receivers.

When configured for multicast, a max number of retransmits is permitted by Configuration.MAX_RESEND_DEFAULT. Additional received NAKs will be ignored if this maximum is reached. When configured for unicast, a single outstanding retransmit is permitted, and additional received NAKs will be ignored iff they overlap the current retransmit - otherwise the previous retransmit is assumed to have 'worked' and the new NAK will take its place.

Constructor Summary

Constructors

Constructor	Description
RetransmitHandler(NanoClock nanoClock, AtomicCounter invalidPackets, FeedbackDelayGenerator delayGenerator, FeedbackDelayGenerator lingerTimeoutGenerator, boolean hasGroupSemantics, int maxRetransmits, AtomicCounter retransmitOverflowCounter)	Create a handler for the dealing with the reception of frame request a frame to be retransmitted.

Method Summary

Modifier and Type	Method	Description
void	onNak(int termId, int termOffset, int length, int termLength, int mtuLength, FlowControl flowControl, RetransmitSender retransmitSender)	Called on reception of a NAK to start retransmit handling.
void	onRetransmitReceived(int termId, int termOffset)	Called to indicate a retransmission is received that may obviate the need to send one ourselves.
void	processTimeouts(long nowNs, RetransmitSender retransmitSender)	Called to process any outstanding timeouts.

Methods inherited from class java.lang.Object

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

Constructor Details

RetransmitHandler

public RetransmitHandler(NanoClock nanoClock,
 AtomicCounter invalidPackets,
 FeedbackDelayGenerator delayGenerator,
 FeedbackDelayGenerator lingerTimeoutGenerator,
 boolean hasGroupSemantics,
 int maxRetransmits,
 AtomicCounter retransmitOverflowCounter)

Create a handler for the dealing with the reception of frame request a frame to be retransmitted.

Parameters:

nanoClock - used to determine time.

invalidPackets - for recording invalid packets.

delayGenerator - to use for delay determination.

lingerTimeoutGenerator - to use for linger timeout.

hasGroupSemantics - indicates multicast/MDC semantics.

maxRetransmits - max retransmits for when group semantics is enabled

retransmitOverflowCounter - counter to track overflows.

Method Details

onNak

public void onNak(int termId,
 int termOffset,
 int length,
 int termLength,
 int mtuLength,
 FlowControl flowControl,
 RetransmitSender retransmitSender)

Called on reception of a NAK to start retransmit handling.

Parameters:

termId - from the NAK and the term id of the buffer to retransmit from.

termOffset - from the NAK and the offset of the data to retransmit.

length - of the missing data.

termLength - of the term buffer.

mtuLength - for the publication.

flowControl - for the publication (to clamp the retransmission length).

retransmitSender - to call if an immediate retransmit is required.

onRetransmitReceived

public void onRetransmitReceived(int termId,
 int termOffset)

Called to indicate a retransmission is received that may obviate the need to send one ourselves.

NOTE: Currently only called from unit tests. Would be used for retransmitting from receivers for NAK suppression.

Parameters:

termId - of the data.

termOffset - of the data.

processTimeouts

public void processTimeouts(long nowNs,
 RetransmitSender retransmitSender)

Called to process any outstanding timeouts.

Parameters:

nowNs - time in nanoseconds.

retransmitSender - to call on retransmissions.