com.iplanet.dpro.session.service

Class PermutationGenerator

java.lang.Object

com.iplanet.dpro.session.service.PermutationGenerator

public class PermutationGenerator
extends Object

Utility class to generate uniformly distributed random permutations of integers in the range 0..size Permutation generation deterministically produces the same result if given the same seed value This class is used to implement enhanced request routing scheme as described in http://is.red.iplanet.com/failover/s1as7/IS62-SessionFailover.sxw

Constructor Summary

Constructors

Constructor and Description
PermutationGenerator(long seed, int size) ConstructsPermutationGenerator
PermutationGenerator(String seed, int size) Constructor

Method Summary

Modifier and Type	Method and Description
short	itemAt(int pos) Returns permutation element at a given position Throws
static void	main(String[] args)

Methods inherited from class java.lang.Object

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

Constructor Detail

PermutationGenerator

public PermutationGenerator(String seed,
                            int size)

Constructor

Parameters:

seed - seed used by RNG

size - permutation size

PermutationGenerator

public PermutationGenerator(long seed,
                            int size)

ConstructsPermutationGenerator

Parameters:

seed - seed used by RNG

size - permutation size

Method Detail

itemAt

public short itemAt(int pos)

Returns permutation element at a given position Throws

Parameters:

pos - permutation element position

Returns:

permutation element value

Throws:

IndexOutOfBoundsException - if index is less than 0 or greater than permutation size specified in constructor

main

public static void main(String[] args)
                 throws Exception

Throws:

Exception