Package io.github.pr0methean.betterrandom.seed

Class RandomSeeder

java.lang.Object

io.github.pr0methean.betterrandom.util.Looper

io.github.pr0methean.betterrandom.seed.RandomSeeder

All Implemented Interfaces:

Serializable

Direct Known Subclasses:

LegacyRandomSeeder

public class RandomSeeder
extends Looper

Thread that loops over ByteArrayReseedableRandom instances and reseeds them. No EntropyCountingRandom will be reseeded when it's already had more input than output.

Author:

Chris Hennick

See Also:

Serialized Form

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
static class	RandomSeeder.DefaultThreadFactory	A ThreadFactory that sets the name and priority of the threads it creates.

Field Summary

Fields

Modifier and Type	Field	Description
protected Set<ByteArrayReseedableRandom>	byteArrayPrngs	Holds ByteArrayReseedableRandom instances that should be reseeded when their entropy is low, or as often as possible if they don't implement EntropyCountingRandom.
protected static long	DEFAULT_STOP_IF_EMPTY_FOR_NANOS	Default waiting time before an empty instance terminates if still empty.
protected static long	FIRST_POLL_INTERVAL	Time in seconds to wait before checking again whether any PRNGs need more entropy, after one iteration when they didn't.
protected static long	REPEAT_POLL_INTERVAL	Time in seconds to wait before checking again whether any PRNGs need more entropy, after more than one iteration when they didn't.
protected SeedGenerator	seedGenerator	The seed generator this seeder uses.
protected long	stopIfEmptyForNanos	Time in nanoseconds after which this thread will terminate if no PRNGs are attached.
protected Condition	waitForEntropyDrain	Signaled by an associated BaseRandom when it runs out of entropy.
protected Condition	waitWhileEmpty	Signaled when a PRNG is added.

Fields inherited from class io.github.pr0methean.betterrandom.util.Looper

DEFAULT_THREAD_FACTORY, factory, lock, thread, threadLock

Constructor Summary

Constructors

Constructor	Description
RandomSeeder(SeedGenerator seedGenerator)	Creates an instance using a RandomSeeder.DefaultThreadFactory.
RandomSeeder(SeedGenerator seedGenerator, ThreadFactory threadFactory)	Creates an instance whose thread will terminate if no PRNGs have been associated with it for 5 seconds.
RandomSeeder(SeedGenerator seedGenerator, ThreadFactory threadFactory, long stopIfEmptyForNanos)	Creates an instance.

Method Summary

Modifier and Type	Method	Description
void	add(ByteArrayReseedableRandom... randoms)	Adds ByteArrayReseedableRandom instances.
void	add(Collection<? extends ByteArrayReseedableRandom> randoms)	Adds ByteArrayReseedableRandom instances.
protected void	clear()	Removes all PRNGs from this seeder.
boolean	contains(Object random)	Checks whether the given PRNG is currently registered with this RandomSeeder.
boolean	equals(Object o)
SeedGenerator	getSeedGenerator()	Returns the SeedGenerator this seeder uses.
int	hashCode()
protected void	initTransientFields()	Initializes the transient instance fields for this class.
boolean	isEmpty()	Returns true if no Random instances are registered with this LegacyRandomSeeder.
protected boolean	iterate()	The task that will be iterated until it returns false.
void	remove(ByteArrayReseedableRandom... randoms)	Removes PRNGs so that they will no longer be reseeded.
void	remove(Collection<? extends ByteArrayReseedableRandom> randoms)	Removes PRNGs so that they will no longer be reseeded.
protected boolean	reseedByteArrayReseedableRandoms(Iterable<? extends ByteArrayReseedableRandom> randoms)	Reseeds all the PRNGs that need reseeding in randoms.
protected void	reseedWithLong(Random random)	Generates an 8-byte seed, converts it to a long and calls Random.setSeed(long).
void	shutDown()	Shut down this thread even if Random instances are registered with it.
protected boolean	stillEmptyAfterWaiting()	Waits stopIfEmptyForNanos for waitWhileEmpty to be signaled
void	stopIfEmpty()	Shut down this thread if no Random instances are registered with it.
protected static void	unregisterWithAll(Set<?> randoms)	Informs the given PRNGs that they no longer have a seed generator.
protected void	waitForEntropyDrainOrUpdateFlag(boolean entropyConsumed)	If entropy was consumed this iteration, waits until wakeUp() is called or the polling interval expires.
void	wakeUp()	Ensures this seeder's thread is started, and signals conditions it may be waiting on.

Methods inherited from class io.github.pr0methean.betterrandom.util.Looper

interrupt, isRunning, start

Methods inherited from class java.lang.Object

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

Field Detail

FIRST_POLL_INTERVAL

protected static final long FIRST_POLL_INTERVAL

Time in seconds to wait before checking again whether any PRNGs need more entropy, after one iteration when they didn't.

See Also:

Constant Field Values

REPEAT_POLL_INTERVAL

protected static final long REPEAT_POLL_INTERVAL

Time in seconds to wait before checking again whether any PRNGs need more entropy, after more than one iteration when they didn't.

See Also:

Constant Field Values

DEFAULT_STOP_IF_EMPTY_FOR_NANOS

protected static final long DEFAULT_STOP_IF_EMPTY_FOR_NANOS

Default waiting time before an empty instance terminates if still empty.

See Also:

Constant Field Values

seedGenerator

protected final SeedGenerator seedGenerator

The seed generator this seeder uses.

byteArrayPrngs

protected transient Set<ByteArrayReseedableRandom> byteArrayPrngs

Holds ByteArrayReseedableRandom instances that should be reseeded when their entropy is low, or as often as possible if they don't implement EntropyCountingRandom.

waitWhileEmpty

protected transient Condition waitWhileEmpty

Signaled when a PRNG is added.

waitForEntropyDrain

protected transient Condition waitForEntropyDrain

Signaled by an associated BaseRandom when it runs out of entropy.

stopIfEmptyForNanos

protected final long stopIfEmptyForNanos

Time in nanoseconds after which this thread will terminate if no PRNGs are attached.

Constructor Detail

RandomSeeder

public RandomSeeder(SeedGenerator seedGenerator,
                    ThreadFactory threadFactory)

Creates an instance whose thread will terminate if no PRNGs have been associated with it for 5 seconds.

Parameters:

seedGenerator - the seed generator

threadFactory - the ThreadFactory that will create this seeder's thread

RandomSeeder

public RandomSeeder(SeedGenerator seedGenerator)

Creates an instance using a RandomSeeder.DefaultThreadFactory.

Parameters:

seedGenerator - the seed generator

RandomSeeder

public RandomSeeder(SeedGenerator seedGenerator,
                    ThreadFactory threadFactory,
                    long stopIfEmptyForNanos)

Creates an instance.

Parameters:

seedGenerator - the seed generator

threadFactory - the ThreadFactory that will create this seeder's thread

stopIfEmptyForNanos - time in nanoseconds after which this thread will terminate if no PRNGs are attached

Method Detail

remove

public void remove(ByteArrayReseedableRandom... randoms)

Removes PRNGs so that they will no longer be reseeded.

Parameters:

randoms - the PRNGs to remove

remove

public void remove(Collection<? extends ByteArrayReseedableRandom> randoms)

Removes PRNGs so that they will no longer be reseeded.

Parameters:

randoms - the PRNGs to remove

contains

public boolean contains(Object random)

Checks whether the given PRNG is currently registered with this RandomSeeder.

Parameters:

random - the PRNG to check the status of

Returns:

true if registered; false if not

add

public void add(ByteArrayReseedableRandom... randoms)

Adds ByteArrayReseedableRandom instances.

Parameters:

randoms - the PRNGs to start reseeding

add

public void add(Collection<? extends ByteArrayReseedableRandom> randoms)

Adds ByteArrayReseedableRandom instances.

Parameters:

randoms - the PRNGs to start reseeding

wakeUp

public void wakeUp()

Ensures this seeder's thread is started, and signals conditions it may be waiting on.

equals

public boolean equals(Object o)

Overrides:

equals in class Object

hashCode

public int hashCode()

Overrides:

hashCode in class Object

initTransientFields

protected void initTransientFields()

Initializes the transient instance fields for this class. Called by constructors and during deserialization.

Overrides:

initTransientFields in class Looper

iterate

protected boolean iterate()

Description copied from class: Looper

The task that will be iterated until it returns false. Cannot be abstract for serialization reasons, but must be overridden in subclasses if they are instantiated without a target Runnable.

Specified by:

iterate in class Looper

Returns:

true if this thread should iterate again.

stillEmptyAfterWaiting

protected boolean stillEmptyAfterWaiting()
                                  throws InterruptedException

Waits stopIfEmptyForNanos for waitWhileEmpty to be signaled

Returns:

true if not signaled; false if signaled

Throws:

InterruptedException - if interrupted

waitForEntropyDrainOrUpdateFlag

protected void waitForEntropyDrainOrUpdateFlag(boolean entropyConsumed)
                                        throws InterruptedException

If entropy was consumed this iteration, waits until wakeUp() is called or the polling interval expires. Updates whether the next polling wait will be short or long.

Parameters:

entropyConsumed - whether entropy was consumed this iteration

Throws:

InterruptedException - if interrupted

reseedByteArrayReseedableRandoms

protected boolean reseedByteArrayReseedableRandoms(Iterable<? extends ByteArrayReseedableRandom> randoms)

Reseeds all the PRNGs that need reseeding in randoms.

Parameters:

randoms - the PRNGs to reseed

Returns:

true if at least one PRNG was reseeded; false otherwise

reseedWithLong

protected void reseedWithLong(Random random)

Generates an 8-byte seed, converts it to a long and calls Random.setSeed(long).

Parameters:

random - the PRNG to reseed

shutDown

public void shutDown()

Shut down this thread even if Random instances are registered with it.

clear

protected void clear()

Removes all PRNGs from this seeder.

unregisterWithAll

protected static void unregisterWithAll(Set<?> randoms)

Informs the given PRNGs that they no longer have a seed generator. Only affects those that support BaseRandom.setRandomSeeder(RandomSeeder).

Parameters:

randoms - the PRNGs to unregister with

isEmpty

public boolean isEmpty()

Returns true if no Random instances are registered with this LegacyRandomSeeder.

Returns:

true if no Random instances are registered with this LegacyRandomSeeder.

stopIfEmpty

public void stopIfEmpty()

Shut down this thread if no Random instances are registered with it.

getSeedGenerator

public SeedGenerator getSeedGenerator()

Returns the SeedGenerator this seeder uses.

Returns:

this seeder's SeedGenerator