Module com.aoapps.io.posix

Package com.aoapps.io.posix.linux

Class DevRandom

java.lang.Object

java.util.Random

com.aoapps.io.posix.linux.DevRandom

All Implemented Interfaces:

Serializable

public class DevRandom
extends Random

This class acts as a direct source of Random data from /dev/random on Linux platforms. Many of these calls are platform-specific and use the included libaocode.so Linux shared library provided as a resource. The source code is also supplied. Please note that reading will block when random data is not available. Use only where the highest quality random data is required and possible delays are acceptable.

Author:

AO Industries, Inc.

See Also:

• Serialized Form

Field Summary

Fields

Modifier and Type	Field	Description
static final String	DEV_RANDOM_PATH	The device file path used to obtain and add random data.
static final PosixFile	devRandomUF	The device file used to obtain and add random data.
static final String	ENTROPY_AVAIL_PATH	The device file path used to obtain the entropy statistics.
static final PosixFile	entropyAvailUF	The device file used to obtain the entropy statistics.
static final String	POOL_SIZE_PATH	The device file path used to obtain the pool size.
static final PosixFile	poolSizeUF	The device file used to obtain the pool size.

Constructor Summary

Constructors

Constructor	Description
DevRandom()

Method Summary

Modifier and Type	Method	Description
static void	addEntropy(byte[] randomData)	Adds random entropy to the kernel.
static void	closeDevRandomIn()	Closes the FileInputStream that reads from /dev/random.
static int	getEntropyAvail()	Gets the number of random bits currently available in the kernel.
static int	getPoolSize()	Gets the number of bits in the random pool in the kernel.
static void	main(String[] args)	Manually adds entropy to the kernel, reads from standard in.
protected int	next(int bits)
boolean	nextBoolean()
void	nextBytes(byte[] bytes)
void	nextBytes(byte[] bytes, int off, int len)	See nextBytes(byte[]).
static void	nextBytesStatic(byte[] bytes)	Static implementation of nextBytes(byte[]).
static void	nextBytesStatic(byte[] bytes, int off, int len)	Static implementation of nextBytes(byte[], int, int).
int	nextInt()
long	nextLong()
static FileInputStream	openDevRandomIn()	Opens the FileInputStream that reads from /dev/random.
void	setSeed(long seed)	This class does not use this seed value.

Methods inherited from class java.util.Random

doubles, doubles, doubles, doubles, ints, ints, ints, ints, longs, longs, longs, longs, nextDouble, nextFloat, nextGaussian, nextInt

Methods inherited from class java.lang.Object

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

Field Details

DEV_RANDOM_PATH

public static final String DEV_RANDOM_PATH

The device file path used to obtain and add random data.

See Also:

• Constant Field Values

devRandomUF

public static final PosixFile devRandomUF

The device file used to obtain and add random data.

ENTROPY_AVAIL_PATH

public static final String ENTROPY_AVAIL_PATH

The device file path used to obtain the entropy statistics.

See Also:

• Constant Field Values

entropyAvailUF

public static final PosixFile entropyAvailUF

The device file used to obtain the entropy statistics.

POOL_SIZE_PATH

public static final String POOL_SIZE_PATH

The device file path used to obtain the pool size.

See Also:

• Constant Field Values

poolSizeUF

public static final PosixFile poolSizeUF

The device file used to obtain the pool size.

Constructor Details

DevRandom

public DevRandom()

Method Details

openDevRandomIn

public static FileInputStream openDevRandomIn()
                                       throws IOException

Opens the FileInputStream that reads from /dev/random.

Throws:

IOException

closeDevRandomIn

public static void closeDevRandomIn()
                             throws IOException

Closes the FileInputStream that reads from /dev/random.

Throws:

IOException

getEntropyAvail

public static int getEntropyAvail()
                           throws IOException

Gets the number of random bits currently available in the kernel.

Throws:

IOException

getPoolSize

public static int getPoolSize()
                       throws IOException

Gets the number of bits in the random pool in the kernel.

Throws:

IOException

addEntropy

public static void addEntropy(byte[] randomData)
                       throws IOException

Adds random entropy to the kernel.

Throws:

IOException

setSeed

public void setSeed(long seed)

This class does not use this seed value.

Overrides:

setSeed in class Random

next

protected int next(int bits)

Overrides:

next in class Random

nextBoolean

public boolean nextBoolean()

Overrides:

nextBoolean in class Random

nextBytes

public void nextBytes(byte[] bytes)

Overrides:

nextBytes in class Random

nextBytes

public void nextBytes(byte[] bytes,
 int off,
 int len)

See nextBytes(byte[]).

nextBytesStatic

public static void nextBytesStatic(byte[] bytes)

Static implementation of nextBytes(byte[]).

nextBytesStatic

public static void nextBytesStatic(byte[] bytes,
 int off,
 int len)

Static implementation of nextBytes(byte[], int, int).

nextInt

public int nextInt()

Overrides:

nextInt in class Random

nextLong

public long nextLong()

Overrides:

nextLong in class Random

main

public static void main(String[] args)

Manually adds entropy to the kernel, reads from standard in.