org.apache.commons.lang3

Class RandomUtils

java.lang.Object

org.apache.commons.lang3.RandomUtils

public class RandomUtils
extends Object

Utility library that supplements the standard Random class.

Caveat: Instances of Random are not cryptographically secure.

Please note that the Apache Commons project provides a component dedicated to pseudo-random number generation, namely Commons RNG, that may be a better choice for applications with more stringent requirements (performance and/or correctness).

Since:

3.3

Constructor Summary

Constructors

Constructor and Description
RandomUtils() RandomUtils instances should NOT be constructed in standard programming.

Method Summary

Modifier and Type	Method and Description
static boolean	nextBoolean() Returns a random boolean value
static byte[]	nextBytes(int count) Creates an array of random bytes.
static double	nextDouble() Returns a random double within 0 - Double.MAX_VALUE
static double	nextDouble(double startInclusive, double endExclusive) Returns a random double within the specified range.
static float	nextFloat() Returns a random float within 0 - Float.MAX_VALUE
static float	nextFloat(float startInclusive, float endExclusive) Returns a random float within the specified range.
static int	nextInt() Returns a random int within 0 - Integer.MAX_VALUE
static int	nextInt(int startInclusive, int endExclusive) Returns a random integer within the specified range.
static long	nextLong() Returns a random long within 0 - Long.MAX_VALUE
static long	nextLong(long startInclusive, long endExclusive) Returns a random long within the specified range.

Methods inherited from class java.lang.Object

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

Constructor Detail

RandomUtils

public RandomUtils()

RandomUtils instances should NOT be constructed in standard programming. Instead, the class should be used as RandomUtils.nextBytes(5);.

This constructor is public to permit tools that require a JavaBean instance to operate.

Method Detail

nextBoolean

public static boolean nextBoolean()

Returns a random boolean value

Returns:

the random boolean

Since:

3.5

nextBytes

public static byte[] nextBytes(int count)

Creates an array of random bytes.

Parameters:

count - the size of the returned array

Returns:

the random byte array

Throws:

IllegalArgumentException - if count is negative

nextInt

public static int nextInt(int startInclusive,
                          int endExclusive)

Returns a random integer within the specified range.

Parameters:

startInclusive - the smallest value that can be returned, must be non-negative

endExclusive - the upper bound (not included)

Returns:

the random integer

Throws:

IllegalArgumentException - if startInclusive > endExclusive or if startInclusive is negative

nextInt

public static int nextInt()

Returns a random int within 0 - Integer.MAX_VALUE

Returns:

the random integer

Since:

3.5

See Also:

nextInt(int, int)

nextLong

public static long nextLong(long startInclusive,
                            long endExclusive)

Returns a random long within the specified range.

Parameters:

startInclusive - the smallest value that can be returned, must be non-negative

endExclusive - the upper bound (not included)

Returns:

the random long

Throws:

IllegalArgumentException - if startInclusive > endExclusive or if startInclusive is negative

nextLong

public static long nextLong()

Returns a random long within 0 - Long.MAX_VALUE

Returns:

the random long

Since:

3.5

See Also:

nextLong(long, long)

nextDouble

public static double nextDouble(double startInclusive,
                                double endExclusive)

Returns a random double within the specified range.

Parameters:

startInclusive - the smallest value that can be returned, must be non-negative

endExclusive - the upper bound (not included)

Returns:

the random double

Throws:

IllegalArgumentException - if startInclusive > endExclusive or if startInclusive is negative

nextDouble

public static double nextDouble()

Returns a random double within 0 - Double.MAX_VALUE

Returns:

the random double

Since:

3.5

See Also:

nextDouble(double, double)

nextFloat

public static float nextFloat(float startInclusive,
                              float endExclusive)

Returns a random float within the specified range.

Parameters:

startInclusive - the smallest value that can be returned, must be non-negative

endExclusive - the upper bound (not included)

Returns:

the random float

Throws:

IllegalArgumentException - if startInclusive > endExclusive or if startInclusive is negative

nextFloat

public static float nextFloat()

Returns a random float within 0 - Float.MAX_VALUE

Returns:

the random float

Since:

3.5

See Also:

nextFloat(float, float)