Package jasima.core.random

Class RandomFactory

java.lang.Object

jasima.core.random.RandomFactory

All Implemented Interfaces:

Serializable

Direct Known Subclasses:

RandomFactoryOld

public class RandomFactory
extends Object
implements Serializable

This class provides functionality to create (independent) random number streams. These streams are dependent on a base seed (setSeed(long)) and a stream name (provided as a parameter to createInstance(String) ).

Behaviour of this class can be modified in two ways using system properties.

1. A property RANDOM_FACTORY_PROP_KEY can be used to change the class returned by the static method newInstance().
2. If just a different implementation of Random is desired (default is MersenneTwister), use the system property RANDOM_CLASS_PROP_KEY.

Author:

Torsten Hildebrandt

See Also:

Serialized Form

Field Summary

Fields

Modifier and Type	Field	Description
static String	RANDOM_CLASS_PROP_KEY
static String	RANDOM_FACTORY_PROP_KEY
static Class<? extends Random>	randomClass
static Class<? extends RandomFactory>	randomFactoryClass

Constructor Summary

Constructors

Constructor	Description
RandomFactory()	This constructor is usually not called directly, use static factory method newInstance() instead.
RandomFactory(Simulation sim, long initialSeed)	Convenience constructor when creating instances directly.

Method Summary

Modifier and Type	Method	Description
Random	createInstance(String name)	Create a new random instance.
Random	createInstance(String name, Consumer<String> warningReceiver)	Create a new random instance.
protected Random	createRandom(long seed)	Create a new Random instance with the given seed.
protected long	getSeed(String name, Consumer<String> warningReceiver)	Compute a (hopefully unique) seed which only depends on 'name' and this RandomFactory's seed.
Simulation	getSim()
DblSequence	initRndGen(DblSequence stream)	Initializes the random number generator of a DblStream if it is not already set using the stream's name.
<T extends DblSequence> T	initRndGen(T stream, String defaultName)	Initializes the random number generator of a DblStream if it is not already set.
static RandomFactory	newInstance()	Factory method to create a new instance of RandomFactory.
static void	reloadSysProps()	Used during tests to change implementation classes while JVM is running.
void	setSeed(long seed)	Sets the seed that is used to initialize all random number streams.
void	setSim(Simulation sim)	Sets the simulation this random factory is currently used with.

Methods inherited from class java.lang.Object

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

Field Detail

RANDOM_FACTORY_PROP_KEY

public static final String RANDOM_FACTORY_PROP_KEY

randomFactoryClass

public static Class<? extends RandomFactory> randomFactoryClass

RANDOM_CLASS_PROP_KEY

public static final String RANDOM_CLASS_PROP_KEY

randomClass

public static Class<? extends Random> randomClass

Constructor Detail

RandomFactory

public RandomFactory()

This constructor is usually not called directly, use static factory method newInstance() instead.

RandomFactory

public RandomFactory(Simulation sim,
                     long initialSeed)

Convenience constructor when creating instances directly.

Method Detail

newInstance

public static RandomFactory newInstance()

Factory method to create a new instance of RandomFactory. The default implementation is to return a new instance of RandomFactory, but the class created can be customized with the system property "jasima.core.random.RandomFactory".

Returns:

A new RandomFactory instance.

createInstance

public Random createInstance(String name)

Create a new random instance. The seed of this new instance (and hence the stream of pseudo-random numbers) is determined by the given name and the seed of the RandomFactory.

Parameters:

name - A unique name of the Random instance (indirectly setting its seed).

Returns:

The new Random instance.

createInstance

public Random createInstance(String name,
                             @Nullable
                             Consumer<String> warningReceiver)

Create a new random instance. The seed of this new instance (and hence the stream of pseudo-random numbers) is determined by the given name and the seed of the RandomFactory.

Parameters:

name - A unique name of the Random instance (indirectly setting its seed).

warningReceiver - used to issue a warning message in case of a hash collision

Returns:

The new Random instance.

createRandom

protected Random createRandom(long seed)

Create a new Random instance with the given seed. The concrete class instantiated is determined by a system property "jasima.core.random.RandomFactory.randomClass" (default: MersenneTwister).

Parameters:

seed - The seed for the new Random instance.

Returns:

A new Random instance initialized with the given seed.

getSeed

protected long getSeed(String name,
                       @Nullable
                       Consumer<String> warningReceiver)

Compute a (hopefully unique) seed which only depends on 'name' and this RandomFactory's seed.

Parameters:

warningReceiver - used to issue a warning message in case of a hash collision

setSeed

public void setSeed(long seed)

Sets the seed that is used to initialize all random number streams.

Parameters:

seed - The seed to use.

initRndGen

public <T extends DblSequence> T initRndGen(T stream,
                                            String defaultName)

Initializes the random number generator of a DblStream if it is not already set. As name of the stream DblSequence.getName() is used. If it is null, defaultName is used instead.

Parameters:

stream - The stream to initialize.

defaultName - Default name if stream provides no useful information.

Returns:

The same as stream.

initRndGen

public DblSequence initRndGen(DblSequence stream)

Initializes the random number generator of a DblStream if it is not already set using the stream's name. This method is the same as initRndGen(DblSequence, String), just without a default name.

Parameters:

stream - The DblSequence to configure.

Returns:

The stream with random number generator initialized.

getSim

public Simulation getSim()

setSim

public void setSim(Simulation sim)

Sets the simulation this random factory is currently used with.

reloadSysProps

public static void reloadSysProps()

Used during tests to change implementation classes while JVM is running.