io.aeron.driver

Class LossDetector

java.lang.Object

io.aeron.driver.LossDetector

All Implemented Interfaces:

TermGapScanner.GapHandler

public class LossDetector
extends java.lang.Object
implements TermGapScanner.GapHandler

Detecting and handling of gaps in a message stream.

Each detector only notifies a single run of a gap in a message stream.

Constructor Summary

Constructors

Constructor and Description
LossDetector(FeedbackDelayGenerator delayGenerator, LossHandler lossHandler) Create a loss detector for a channel.

Method Summary

Modifier and Type	Method and Description
static boolean	lossFound(long scanOutcome) Has loss been found in the scan?
void	onGap(int termId, int offset, int length) Gap detected in log buffer that is being rebuilt.
static long	pack(int rebuildOffset, boolean lossFound) Pack the values for workCount and rebuildOffset into a long for returning on the stack.
static int	rebuildOffset(long scanOutcome) The offset up to which the log has been rebuilt.
long	scan(org.agrona.concurrent.UnsafeBuffer termBuffer, long rebuildPosition, long hwmPosition, long nowNs, int termLengthMask, int positionBitsToShift, int initialTermId) Scan for gaps and handle received data.

Methods inherited from class java.lang.Object

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

Constructor Detail

LossDetector

public LossDetector(FeedbackDelayGenerator delayGenerator,
                    LossHandler lossHandler)

Create a loss detector for a channel.

Parameters:

delayGenerator - to use for delay determination

lossHandler - to call when signalling a gap

Method Detail

scan

public long scan(org.agrona.concurrent.UnsafeBuffer termBuffer,
                 long rebuildPosition,
                 long hwmPosition,
                 long nowNs,
                 int termLengthMask,
                 int positionBitsToShift,
                 int initialTermId)

Scan for gaps and handle received data.

The handler keeps track from scan to scan what is a gap and what must have been repaired.

Parameters:

termBuffer - to scan

rebuildPosition - to start scanning from

hwmPosition - to scan up to

nowNs - time in nanoseconds

termLengthMask - used for offset calculation

positionBitsToShift - used for position calculation

initialTermId - used by the scanner

Returns:

packed outcome of the scan.

onGap

public void onGap(int termId,
                  int offset,
                  int length)

Description copied from interface: TermGapScanner.GapHandler

Gap detected in log buffer that is being rebuilt.

Specified by:

onGap in interface TermGapScanner.GapHandler

Parameters:

termId - active term being scanned.

offset - at which the gap begins.

length - of the gap in bytes.

pack

public static long pack(int rebuildOffset,
                        boolean lossFound)

Pack the values for workCount and rebuildOffset into a long for returning on the stack.

Parameters:

rebuildOffset - value to be packed.

lossFound - value to be packed.

Returns:

a long with rebuildOffset and lossFound packed into it.

lossFound

public static boolean lossFound(long scanOutcome)

Has loss been found in the scan?

Parameters:

scanOutcome - into which the fragments read value has been packed.

Returns:

if loss has been found or not.

rebuildOffset

public static int rebuildOffset(long scanOutcome)

The offset up to which the log has been rebuilt.

Parameters:

scanOutcome - into which the offset value has been packed.

Returns:

the offset up to which the log has been rebuilt.