com.github.f4b6a3.uuid.timestamp

Class DefaultTimestampStrategy

java.lang.Object

com.github.f4b6a3.uuid.sequence.AbstractSequence

com.github.f4b6a3.uuid.timestamp.DefaultTimestampStrategy

All Implemented Interfaces:

Sequence, TimestampStrategy

Direct Known Subclasses:

StoppedDefaultTimestampStrategy

public class DefaultTimestampStrategy
extends AbstractSequence
implements TimestampStrategy

This is an implementation of TimestampStrategy that provides millisecond resolution. The timestamp resolution is simulated by adding the value of a counter that is incremented at every call to the method TimestampStrategy.getTimestamp(). The counter's range is from 0 to 9,999, that is, the number of 100-nanosecond intervals per millisecond. The counter is initialized with a random number between 0 and 255 to void duplicates in the case of multiple time-based generators running in different JVMs. ### RFC-4122 - 4.2.1.2. System Clock Resolution (4) A high resolution timestamp can be simulated by keeping a count of the number of UUIDs that have been generated with the same value of the system time, and using it to construct the low order bits of the timestamp. The count will range between zero and the number of 100-nanosecond intervals per system time interval. ### RFC-4122 - 4.2.1.2. System Clock Resolution (3c) If a system overruns the generator by requesting too many UUIDs within a single system time interval, the UUID service MUST either return an error, or stall the UUID generator until the system clock catches up.

Field Summary

Fields

Modifier and Type	Field and Description
protected static int	COUNTER_MAX
protected static int	COUNTER_MIN
protected static int	COUNTER_OFFSET_MAX
protected static String	OVERRUN_MESSAGE
protected long	previousTimestamp

Fields inherited from class com.github.f4b6a3.uuid.sequence.AbstractSequence

maxValue, minValue, value

Constructor Summary

Constructors

Constructor and Description
DefaultTimestampStrategy()

Method Summary

Modifier and Type	Method and Description
protected int	getNextCounter(long timestamp) Get the next counter value.
long	getTimestamp()
int	next()
void	reset()

Methods inherited from class com.github.f4b6a3.uuid.sequence.AbstractSequence

current, max, min, set

Methods inherited from class java.lang.Object

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

Field Detail

previousTimestamp

protected long previousTimestamp

COUNTER_MIN

protected static final int COUNTER_MIN

See Also:

Constant Field Values

COUNTER_MAX

protected static final int COUNTER_MAX

See Also:

Constant Field Values

COUNTER_OFFSET_MAX

protected static final int COUNTER_OFFSET_MAX

See Also:

Constant Field Values

OVERRUN_MESSAGE

protected static final String OVERRUN_MESSAGE

See Also:

Constant Field Values

Constructor Detail

DefaultTimestampStrategy

public DefaultTimestampStrategy()

Method Detail

getTimestamp

public long getTimestamp()

Specified by:

getTimestamp in interface TimestampStrategy

getNextCounter

protected int getNextCounter(long timestamp)

Get the next counter value.

Parameters:

timestamp - a timestamp

Returns:

the next counter value

next

public int next()

Specified by:

next in interface Sequence

Overrides:

next in class AbstractSequence

reset

public void reset()

Specified by:

reset in interface Sequence

Overrides:

reset in class AbstractSequence