com.github.f4b6a3.uuid.clockseq

Class ClockSequenceController

java.lang.Object

com.github.f4b6a3.uuid.clockseq.ClockSequenceController

public class ClockSequenceController
extends Object

Class that controls the usage of clock sequence values from 0 to 16383. It manages a pool of 16384 values. The pool is implemented as an array of 2048 bytes (16384 bits). Each bit of this array corresponds to a pool value.

Field Summary

Fields

Modifier and Type	Field and Description
protected byte[]	pool
protected static int	POOL_MAX

Constructor Summary

Constructors

Constructor and Description
ClockSequenceController()

Method Summary

Modifier and Type	Method and Description
int	borrow(int give, int take) Borrow a value from the pool and give back another value to the same pool.
void	clearPool() Clear all bits of the byte array that represents the pool.
int	countFree() Count the free values in the pool.
int	countUsed() Count the used values out of the pool.
boolean	isFree(int value) Check if a value is free in the pool.
boolean	isUsed(int value) Check if a value is used out of the pool.

Methods inherited from class java.lang.Object

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

Field Detail

pool

protected byte[] pool

POOL_MAX

protected static final int POOL_MAX

See Also:

Constant Field Values

Constructor Detail

ClockSequenceController

public ClockSequenceController()

Method Detail

borrow

public int borrow(int give,
                  int take)

Borrow a value from the pool and give back another value to the same pool. If the value to be borrowed is already in use, it is incremented until a free value is found and returned. In the case that all pool values are in use, the pool is cleared and the last incremented value is returned. It does nothing to negative arguments.

Parameters:

give - value to be given back to the pool

take - value to be taken from the pool

Returns:

the value to be borrowed if not used.

isUsed

public boolean isUsed(int value)

Check if a value is used out of the pool.

Parameters:

value - a value to be checked in the pool.

Returns:

true if the value is used.

isFree

public boolean isFree(int value)

Check if a value is free in the pool.

Parameters:

value - a value to be checked in the pool.

Returns:

true if the value is free.

countUsed

public int countUsed()

Count the used values out of the pool.

Returns:

the count of used values.

countFree

public int countFree()

Count the free values in the pool.

Returns:

the count of free values.

clearPool

public void clearPool()

Clear all bits of the byte array that represents the pool. This corresponds to marking all pool values as free.