Interface LogFormatter.TimestampFormatter

All Superinterfaces:

LogFormatter

All Known Implementing Classes:

LogFormatter.NoopFormatter

Enclosing interface:

LogFormatter

public static sealed interface LogFormatter.TimestampFormatter
extends LogFormatter
permits LogFormatter.NoopFormatter (not exhaustive)

Formats event timestamps.

Nested Class Summary

Nested classes/interfaces inherited from interface LogFormatter

LogFormatter.Builder, LogFormatter.EventFormatter, LogFormatter.KeyValueNullStrategy, LogFormatter.LevelFormatter, LogFormatter.NoopFormatter, LogFormatter.StaticFormatter, LogFormatter.ThrowableFormatter, LogFormatter.TimestampFormatter

Modifier and Type	Interface	Description
static final class	LogFormatter.Builder	Log formatter builder that is composed of other formatters.
static interface	LogFormatter.EventFormatter	Generic event formatting that is lambda friendly.
static enum	LogFormatter.KeyValueNullStrategy	Controls how a null key value is handled by formatters that print a selected subset of keys (e.g.
static interface	LogFormatter.LevelFormatter	Formats a System.Logger.Level.
static enum	LogFormatter.NoopFormatter	A special formatter that will do nothing.
static final record	LogFormatter.StaticFormatter	A special formatter that will append static text.
static interface	LogFormatter.ThrowableFormatter	Formats a throwable.
static interface	LogFormatter.TimestampFormatter	Formats event timestamps.

Field Summary

Fields

Modifier and Type	Field	Description
static final String	TTLL_TIME_FORMAT	The default timestamp format used in many logging frameworks which does not have dates and only time at millisecond precision.

Method Summary

Modifier and Type	Method	Description
default void	format(StringBuilder output, LogEvent event)	Formats a log event.
void	formatTimestamp(StringBuilder output, Instant instant)	Format timestamp.
static LogFormatter.TimestampFormatter	of()	Formats timestamp using TTLL_TIME_FORMAT.
static LogFormatter.TimestampFormatter	of(DateTimeFormatter dateTimeFormatter)	Formats a timestamp using standard JDK date time formatter.
static LogFormatter.TimestampFormatter	of(DateTimeFormatter dateTimeFormatter, boolean cacheMillisecondPrecision)	Formats a timestamp using standard JDK date time formatter.
static LogFormatter.TimestampFormatter	ofISO()	Formats a timestamp using ISO format at fixed millisecond precision (e.g.
static LogFormatter.TimestampFormatter	ofMicros()	Micro seconds over the events last second.

Methods inherited from interface LogFormatter

isNoop

Modifier and Type	Method	Description
default boolean	isNoop()	Ask the formatter if will do anything.

Field Details

TTLL_TIME_FORMAT

static final String TTLL_TIME_FORMAT

The default timestamp format used in many logging frameworks which does not have dates and only time at millisecond precision.

It is called TTLL as that is the name of the format where it is used in logback, log4j etc.

See Also:

• Constant Field Values

Method Details

formatTimestamp

void formatTimestamp(StringBuilder output,
 Instant instant)

Format timestamp.

Parameters:

output - buffer.

instant - timestamp.

format

default void format(StringBuilder output,
 LogEvent event)

Description copied from interface: LogFormatter

Formats a log event.

Specified by:

format in interface LogFormatter

Parameters:

output - buffer.

event - log event.

See Also:

• LogFormatter.EventFormatter

of

static LogFormatter.TimestampFormatter of()

Formats timestamp using TTLL_TIME_FORMAT.

Returns:

formatter.

ofISO

static LogFormatter.TimestampFormatter ofISO()

Formats a timestamp using ISO format at fixed millisecond precision (e.g. 2023-11-14T22:13:20.123Z, always exactly 3 fractional digits). Pair with ofMicros() to append additional sub-millisecond digits, similar to Logback's %d{ISO8601}%microsecond.

Returns:

formatter.

ofMicros

static LogFormatter.TimestampFormatter ofMicros()

Micro seconds over the events last second. This is for logback compatibility.

Returns:

microseconds zero padded.

of

static LogFormatter.TimestampFormatter of(DateTimeFormatter dateTimeFormatter)

Formats a timestamp using standard JDK date time formatter.

Parameters:

dateTimeFormatter - date time formatter.

Returns:

timestamp formatter.

of

static LogFormatter.TimestampFormatter of(DateTimeFormatter dateTimeFormatter,
 boolean cacheMillisecondPrecision)

Formats a timestamp using standard JDK date time formatter.

Formatting with DateTimeFormatter is comparatively expensive to do on every event, so if the caller knows the formatter's finest resolution is milliseconds (e.g. a pattern using at most SSS, never n/N nanosecond fields), cacheMillisecondPrecision can be set to true to reuse the previously formatted string whenever consecutive events land in the same millisecond - the same trick Logback's CachingDateFormatter and Log4j2's FixedDateFormat use. Passing true for a formatter that can actually render sub-millisecond precision will silently truncate that precision, so only pass true when the pattern is known to not exceed millisecond resolution.

Parameters:

dateTimeFormatter - date time formatter.

cacheMillisecondPrecision - true if the formatter's output is fully determined by the instant's millisecond value.

Returns:

timestamp formatter.