com.github.f4b6a3.uuid.util

Class UuidTime

java.lang.Object

com.github.f4b6a3.uuid.util.UuidTime

public final class UuidTime
extends Object

Utility for UUID time stamps.

The UUID time stamp is a 60-bit number.

The UUID time stamp resolution is 100ns, i.e., the UUID clock ticks every 100-nanosecond interval.

In JDK 8, Instant.now() has millisecond precision, in spite of Instant has nanoseconds resolution. In JDK 9+,Instant.now() has microsecond precision.

See Also:

Current time in microseconds in java, Increase the precision of the implementation of java.time.Clock.systemUTC()

Field Summary

Fields

Modifier and Type	Field and Description
static Instant	EPOCH_GREG The Gregorian epoch.
static long	EPOCH_GREG_SECONDS The Gregorian epoch in seconds.
static Instant	EPOCH_UNIX The Unix epoch.
static long	EPOCH_UNIX_SECONDS The Unix epoch in seconds.
static long	NANOS_PER_TICK Number nanos per clock tick.
static long	TICKS_PER_MILLI Number of clock ticks per millisecond.
static long	TICKS_PER_SECOND Number of clock ticks per second.

Method Summary

Modifier and Type	Method and Description
static Instant	fromGregTimestamp(long gregTimestamp) Converts a number of 100ns since 1582-10-15 (Gregorian epoch) into an Instant.
static Instant	fromUnixTimestamp(long unixTimestamp) Converts a number of 100ns since 1970-01-01 (Unix epoch) into an Instant.
static long	getGregTimestamp() Returns the number of 100ns since 1582-10-15 (Gregorian epoch).
static long	getUnixTimestamp() Returns the number of 100ns since 1970-01-01 (Unix epoch).
static long	toGregTimestamp(Instant instant) Converts an Instant into a number of 100ns since 1582-10-15 (Gregorian epoch).
static long	toGregTimestamp(long unixTimestamp) Converts a number of 100ns since 1970-01-01 (Unix epoch) into a number of 100ns since 1582-10-15 (Gregorian epoch).
static long	toUnixTimestamp(Instant instant) Converts an Instant into a number of 100ns since 1970-01-01 (Unix epoch).
static long	toUnixTimestamp(long gregTimestamp) Converts a number of 100ns since 1582-10-15 (Gregorian epoch) into a number of 100ns since 1970-01-01 (Unix epoch).

Methods inherited from class java.lang.Object

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

Field Detail

EPOCH_UNIX

public static final Instant EPOCH_UNIX

The Unix epoch.

EPOCH_GREG

public static final Instant EPOCH_GREG

The Gregorian epoch.

EPOCH_UNIX_SECONDS

public static final long EPOCH_UNIX_SECONDS

The Unix epoch in seconds.

EPOCH_GREG_SECONDS

public static final long EPOCH_GREG_SECONDS

The Gregorian epoch in seconds.

NANOS_PER_TICK

public static final long NANOS_PER_TICK

Number nanos per clock tick.

See Also:

Constant Field Values

TICKS_PER_MILLI

public static final long TICKS_PER_MILLI

Number of clock ticks per millisecond.

See Also:

Constant Field Values

TICKS_PER_SECOND

public static final long TICKS_PER_SECOND

Number of clock ticks per second.

See Also:

Constant Field Values

Method Detail

getUnixTimestamp

public static long getUnixTimestamp()

Returns the number of 100ns since 1970-01-01 (Unix epoch).

It uses Instant.now() to get the the current time.

Returns:

a number of 100ns since 1970-01-01 (Unix epoch).

getGregTimestamp

public static long getGregTimestamp()

Returns the number of 100ns since 1582-10-15 (Gregorian epoch).

It uses Instant.now() to get the the current time.

Returns:

a number of 100ns since 1582-10-15 (Gregorian epoch).

toUnixTimestamp

public static long toUnixTimestamp(long gregTimestamp)

Converts a number of 100ns since 1582-10-15 (Gregorian epoch) into a number of 100ns since 1970-01-01 (Unix epoch).

Parameters:

gregTimestamp - a number of 100ns since 1582-10-15 (Gregorian epoch)

Returns:

a number of 100ns since 1970-01-01 (Unix epoch)

toGregTimestamp

public static long toGregTimestamp(long unixTimestamp)

Converts a number of 100ns since 1970-01-01 (Unix epoch) into a number of 100ns since 1582-10-15 (Gregorian epoch).

Parameters:

unixTimestamp - a number of 100ns since 1970-01-01 (Unix epoch)

Returns:

a number of 100ns since 1582-10-15 (Gregorian epoch).

toUnixTimestamp

public static long toUnixTimestamp(Instant instant)

Converts an Instant into a number of 100ns since 1970-01-01 (Unix epoch).

Parameters:

instant - an instant

Returns:

a number of 100ns since 1970-01-01 (Unix epoch).

toGregTimestamp

public static long toGregTimestamp(Instant instant)

Converts an Instant into a number of 100ns since 1582-10-15 (Gregorian epoch).

Parameters:

instant - an instant

Returns:

a number of 100ns since 1582-10-15 (Gregorian epoch).

fromUnixTimestamp

public static Instant fromUnixTimestamp(long unixTimestamp)

Converts a number of 100ns since 1970-01-01 (Unix epoch) into an Instant.

Parameters:

unixTimestamp - a number of 100ns since 1970-01-01 (Unix epoch)

Returns:

an instant

fromGregTimestamp

public static Instant fromGregTimestamp(long gregTimestamp)

Converts a number of 100ns since 1582-10-15 (Gregorian epoch) into an Instant.

Parameters:

gregTimestamp - a number of 100ns since 1582-10-15 (Gregorian epoch)

Returns:

an instant