org.mbari.siam.distributed
Interface SequenceGenerator

All Known Implementing Classes:

SequenceNumber

public interface SequenceGenerator

A SequenceGenerator generates a (thread-safe) sequence of (long) integers. The sequence may be implemented in a number of ways: simple up/down counters, state machines, table-driven, non-linear functions... The sequence may implement special behavior at the upper/lower limits of the sequence. The SequenceGenerator interface suggests the basic methods needed to implement such counters. A more general purpose approach might be to use this interface as the basis for a number of abstract adapter classes which could be extended to implement sequences of floating point numbers.

Author:

Kent Headley

Method Summary

long	getGreatest() Get maximum value in sequence
long	getLeast() Get minimum value in sequence
long	getNext() Get next number in sequence
void	initialize(long least, long greatest, long current) Set sequence range
long	peek(long offset, boolean wrap) Look at nth number in sequence (relative to the current number) without actually incrementing.
void	reset() Restart sequence from minimum value

Method Detail

getNext

long getNext()

Get next number in sequence

getLeast

long getLeast()

Get minimum value in sequence

getGreatest

long getGreatest()

Get maximum value in sequence

initialize

void initialize(long least,
                long greatest,
                long current)
                throws RangeException

Set sequence range

Throws:

RangeException

reset

void reset()

Restart sequence from minimum value

peek

long peek(long offset,
          boolean wrap)

Look at nth number in sequence (relative to the current number) without actually incrementing. The offset may be less than zero. Using an offset of 0 returns the most recent number returned.