net.openhft.chronicle.queue

Interface RollCycle

All Known Implementing Classes:

RollCycles

public interface RollCycle

Method Summary

Modifier and Type	Method and Description
int	current(net.openhft.chronicle.core.time.TimeProvider time, long epoch)
int	defaultIndexCount()
int	defaultIndexSpacing() Returns the space between excerpts that are explicitly indexed.
String	format() Returns the format that is to be applied when file names are calculated for a new roll cycle.
int	length() Returns the length in milliseconds (i.e.
int	toCycle(long index) Returns the cycle for the given index.
long	toIndex(int cycle, long sequenceNumber) Returns the index for the given cycle and sequenceNumber.
long	toSequenceNumber(long index) Returns the sequence number for the given index.

Method Detail

format

String format()

Returns the format that is to be applied when file names are calculated for a new roll cycle.

For example, the following formats can be returned:

• "yyyyMMdd-HHmm" (MINUTELY)
• "yyyyMMdd" (DAILY)

Returns:

the format that is to be applied when file names are calculated for a new roll cycle

length

int length()

Returns the length in milliseconds (i.e. the maximum duration) for a roll cycle.

For example, the following lengths can be returned:

• 60 * 1,000 = 60,000 (MINUTELY)
• 24 * 60 * 60 * 1,000 = 86,400,000 (DAILY)

Returns:

the length in milliseconds (i.e. the maximum duration) for a roll cycle

defaultIndexCount

int defaultIndexCount()

defaultIndexSpacing

int defaultIndexSpacing()

Returns the space between excerpts that are explicitly indexed.

A higher number means higher sequential write performance but slower random access read. The sequential read performance is not affected by this property.

For example, the following default index spacing can be returned:

• 16 (MINUTELY)
• 64 (DAILY)

Returns:

the space between excerpts that are explicitly indexed

current

int current(net.openhft.chronicle.core.time.TimeProvider time,
            long epoch)

Parameters:

epoch - and EPOCH offset, to all the user to define their own epoch

Returns:

the cycle

toIndex

long toIndex(int cycle,
             long sequenceNumber)

Returns the index for the given cycle and sequenceNumber.

An index is comprised of both a cycle and a sequence number but the way the index is composed of said properties may vary.

Parameters:

cycle - to be composed into an index

sequenceNumber - to be composed into an index

Returns:

the index for the given cycle and sequenceNumber

toSequenceNumber

long toSequenceNumber(long index)

Returns the sequence number for the given index.

An index is comprised of both a cycle and a sequence number but the way the index is composed of said properties may vary. This method decomposes the provided index and extracts the sequence number.

Parameters:

index - to use when extracting the sequence number

Returns:

the sequence number for the given index

toCycle

int toCycle(long index)

Returns the cycle for the given index.

An index is comprised of both a cycle and a sequence number but the way the index is composed of said properties may vary. This method decomposes the provided index and extracts the cycle.

Parameters:

index - to use when extracting the cycle

Returns:

the sequence number for the given index