io.aeron.driver

Class AbstractMinMulticastFlowControl

java.lang.Object

io.aeron.driver.AbstractMinMulticastFlowControl

All Implemented Interfaces:

FlowControl

Direct Known Subclasses:

MinMulticastFlowControl, TaggedMulticastFlowControl

public abstract class AbstractMinMulticastFlowControl
extends Object
implements FlowControl

Abstract minimum multicast sender flow control strategy. It supports the concept of only tracking the minimum of a group of receivers, not all possible receivers. However, it is agnostic of how that group is determined.

Tracking of receivers is done as long as they continue to send Status Messages. Once SMs stop, the receiver tracking for that receiver will timeout after a given number of nanoseconds.

Constructor Summary

Constructors

Modifier	Constructor and Description
protected	AbstractMinMulticastFlowControl(boolean isGroupTagAware) Base constructor for use by specialised implementations.

Method Summary

Modifier and Type	Method and Description
protected int	groupMinSize() The minimum group size required for progress.
protected long	groupTag() The tag used to identify members of the group.
protected boolean	hasGroupTag() Indicates if the flow control strategy has a group tag it is aware of for tracking membership.
boolean	hasRequiredReceivers() Has the observed receiver count reached the groupMinSize() threshold?
void	initialize(MediaDriver.Context context, UdpChannel udpChannel, int initialTermId, int termBufferLength) Initialize the flow control strategy for a stream.
long	onIdle(long timeNs, long senderLimit, long senderPosition, boolean isEos) Perform any maintenance needed by the flow control strategy and return current sender limit position.
protected long	processStatusMessage(StatusMessageFlyweight flyweight, long senderLimit, int initialTermId, int positionBitsToShift, long timeNs, boolean matchesTag) Process a received status message.
protected long	receiverTimeoutNs() Timeout after which an inactive receiver will be dropped.

Methods inherited from class java.lang.Object

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

Methods inherited from interface io.aeron.driver.FlowControl

onStatusMessage

Constructor Detail

AbstractMinMulticastFlowControl

protected AbstractMinMulticastFlowControl(boolean isGroupTagAware)

Base constructor for use by specialised implementations.

Parameters:

isGroupTagAware - true if the group tag is used.

Method Detail

initialize

public void initialize(MediaDriver.Context context,
                       UdpChannel udpChannel,
                       int initialTermId,
                       int termBufferLength)

Initialize the flow control strategy for a stream.

Specified by:

initialize in interface FlowControl

Parameters:

context - to allow access to media driver configuration

udpChannel - for the stream.

initialTermId - at which the stream started.

termBufferLength - to use as the length of each term buffer.

onIdle

public long onIdle(long timeNs,
                   long senderLimit,
                   long senderPosition,
                   boolean isEos)

Perform any maintenance needed by the flow control strategy and return current sender limit position.

Specified by:

onIdle in interface FlowControl

Parameters:

timeNs - current time in nanoseconds.

senderLimit - for the current sender position.

senderPosition - which has been sent.

isEos - is this end-of-stream for the sender.

Returns:

the position limit to be employed by the sender.

hasRequiredReceivers

public boolean hasRequiredReceivers()

Has the observed receiver count reached the groupMinSize() threshold?

Specified by:

hasRequiredReceivers in interface FlowControl

Returns:

true if the observed receiver count reached the groupMinSize() threshold?

processStatusMessage

protected final long processStatusMessage(StatusMessageFlyweight flyweight,
                                          long senderLimit,
                                          int initialTermId,
                                          int positionBitsToShift,
                                          long timeNs,
                                          boolean matchesTag)

Process a received status message.

Parameters:

flyweight - mapped over the status message.

senderLimit - the sender is currently limited to for sending.

initialTermId - for the publication.

positionBitsToShift - when calculating term length with requiring a divide.

timeNs - current time.

matchesTag - if the status messages comes from a receiver with a tag matching the group.

Returns:

the new position limit to be employed by the sender.

receiverTimeoutNs

protected final long receiverTimeoutNs()

Timeout after which an inactive receiver will be dropped.

Returns:

timeout after which an inactive receiver will be dropped.

hasGroupTag

protected final boolean hasGroupTag()

Indicates if the flow control strategy has a group tag it is aware of for tracking membership.

Returns:

true if the flow control strategy has a group tag it is aware of for tracking membership.

groupTag

protected final long groupTag()

The tag used to identify members of the group.

Returns:

tag used to identify members of the group.

groupMinSize

protected final int groupMinSize()

The minimum group size required for progress.

Returns:

minimum group size required for progress.