cardgame
Class RandomIntGenerator

java.lang.Object
  |
  +--cardgame.RandomIntGenerator

public final class RandomIntGenerator

extends java.lang.Object

The RandomIntGenerator class provides a way to generate random integers within a specific range. It also takes care of reseeding the random number generator after the sequence has been in use for a long time. The default minimum and maximum values have been optimized for use with card games.

Originally appeared in Java Pro, August 2000, page 68.

Version:

1.0, 31 July 2001

Author:

James A. Webb, www.uberkode.com

Field Summary

static int	DEFAULT_MAXIMUM_RANGE The public variable DEFAULT_MAXIMUM_RANGE defines the largest integer that will be generated when the no-argument constructor is used.
static int	DEFAULT_MINIMUM_RANGE The public variable DEFAULT_MINIMUM_RANGE defines the smallest integer that will be generated when the no-argument constructor is used.
private int	maximumRange The private variable maximumRange defines the largest integer that will be generated and is set by the setRange method.
private int	minimumRange The private variable minimumRange defines the smallest integer that will be generated and is set by the setRange method.
private long	numberOfCalls The private variable numberOfCalls keeps track of the number of integers that have been generated.
private java.util.Random	random The private variable random is a Java Random class object.
private int	range The private variable range defines the number of integers that will be generated and is calculated in the setRange method.

Constructor Summary

RandomIntGenerator()
The no-argument constructor creates random numbers within the default limits by supplying the defaults to the two-argument constructor.

RandomIntGenerator(int minRange, int maxRange)
This constructor creates random numbers within user-specified limits.

Method Summary

int	nextRandomInt() The public method nextRandomInt is used to generate and return the next random integer.
private void	setRange(int minRange, int maxRange) The private method setRange is used by the constructors to set the minimum and maximum range.

Methods inherited from class java.lang.Object

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

Field Detail

DEFAULT_MINIMUM_RANGE

public static final int DEFAULT_MINIMUM_RANGE

The public variable DEFAULT_MINIMUM_RANGE defines the smallest integer that will be generated when the no-argument constructor is used.

See Also:

RandomIntGenerator(), DEFAULT_MAXIMUM_RANGE

DEFAULT_MAXIMUM_RANGE

public static final int DEFAULT_MAXIMUM_RANGE

The public variable DEFAULT_MAXIMUM_RANGE defines the largest integer that will be generated when the no-argument constructor is used.

See Also:

RandomIntGenerator(), DEFAULT_MINIMUM_RANGE

minimumRange

private int minimumRange

The private variable minimumRange defines the smallest integer that will be generated and is set by the setRange method.

See Also:

maximumRange, setRange(int minRange, int maxRange)

maximumRange

private int maximumRange

The private variable maximumRange defines the largest integer that will be generated and is set by the setRange method.

See Also:

minimumRange, setRange(int minRange, int maxRange)

range

private int range

The private variable range defines the number of integers that will be generated and is calculated in the setRange method.

See Also:

setRange(int minRange, int maxRange)

numberOfCalls

private long numberOfCalls

The private variable numberOfCalls keeps track of the number of integers that have been generated. It is initially set to zero when a new RandomIntGenerator object is constructed. It is tested and reset within the nextRandomInt method.

See Also:

RandomIntGenerator(), RandomIntGenerator(int minRange, int maxRange), nextRandomInt()

random

private java.util.Random random

The private variable random is a Java Random class object. It is constructed using the current system time as a seed. It is reset when needed within the nextRandomInt method.

See Also:

nextRandomInt()

Constructor Detail

RandomIntGenerator

public RandomIntGenerator()

The no-argument constructor creates random numbers within the default limits by supplying the defaults to the two-argument constructor.

See Also:

DEFAULT_MINIMUM_RANGE, DEFAULT_MAXIMUM_RANGE, RandomIntGenerator(int minRange, int maxRange)

RandomIntGenerator

public RandomIntGenerator(int minRange,
                          int maxRange)

This constructor creates random numbers within user-specified limits.

Parameters:

minRange - the smallest number to be generated as an int.

maxRange - the largest number to be generated as an int.

See Also:

minimumRange, maximumRange, setRange(int minRange, int maxRange), random, numberOfCalls

Method Detail

setRange

private void setRange(int minRange,
                      int maxRange)

The private method setRange is used by the constructors to set the minimum and maximum range. It also calculates and sets the overall range (number of integers that will be generated).

Parameters:

minRange - the smallest number to be generated as an int.

maxRange - the largest number to be generated as an int.

See Also:

minimumRange, maximumRange, range

nextRandomInt

public int nextRandomInt()

The public method nextRandomInt is used to generate and return the next random integer.

Returns:

the next random number as an int.

See Also:

random, numberOfCalls