org.jgap.impl
Class BooleanGene

java.lang.Object
  org.jgap.impl.BooleanGene

All Implemented Interfaces:

java.lang.Comparable, Gene, java.io.Serializable

public class BooleanGene

extends java.lang.Object

implements Gene

A Gene implementation that supports two possible values (alleles) for each gene: true and false.

NOTE: Since this Gene implementation only supports two different values (true and false), there's only a 50% chance that invocation of the setToRandomValue() method will actually change the value of this Gene (if it has a value). As a result, it may be desirable to use a higher overall mutation rate when this Gene implementation is in use.

Since:

1.0

Author:

Neil Rotstan, Klaus Meffert

See Also:

Serialized Form

Field Summary

Fields inherited from interface org.jgap.Gene

PERSISTENT_FIELD_DELIMITER

Constructor Summary

BooleanGene()
Constructs a new BooleanGene with default settings.

Method Summary

void	applyMutation(int index, double a_percentage) Applies a mutation of a given intensity (percentage) onto the atomic element at given index
boolean	booleanValue() Retrieves the boolean value of this Gene.
void	cleanup() Executed by the genetic engine when this Gene instance is no longer needed and should perform any necessary resource cleanup.
int	compareTo(java.lang.Object other) Compares this BooleanGene with the specified object for order.
boolean	equals(java.lang.Object other) Compares this BooleanGene with the given object and returns true if the other object is a BooleanGene and has the same value as this BooleanGene.
java.lang.Object	getAllele() Retrieves the value represented by this Gene.
java.lang.String	getPersistentRepresentation() Retrieves a string representation of this Gene that includes any information required to reconstruct it at a later time, such as its value and internal state.
int	hashCode() Retrieves the hash code value of this BooleanGene.
Gene	newGene() Provides an implementation-independent means for creating new Gene instances.
void	setAllele(java.lang.Object a_newValue) Sets the value of this Gene to the new given value.
void	setToRandomValue(RandomGenerator a_numberGenerator) Sets the value (allele) of this Gene to a random legal value.
void	setValueFromPersistentRepresentation(java.lang.String a_representation) Sets the value and internal state of this Gene from the string representation returned by a previous invocation of the getPersistentRepresentation() method.
int	size()
java.lang.String	toString() Retrieves a string representation of this BooleanGene's value that may be useful for display purposes.

Methods inherited from class java.lang.Object

getClass, notify, notifyAll, wait, wait, wait

Constructor Detail

BooleanGene

public BooleanGene()

Constructs a new BooleanGene with default settings.

Method Detail

newGene

public Gene newGene()

Provides an implementation-independent means for creating new Gene instances. The new instance that is created and returned should be setup with any implementation-dependent configuration that this Gene instance is setup with (aside from the actual value, of course). For example, if this Gene were setup with bounds on its value, then the Gene instance returned from this method should also be setup with those same bounds. This is important, as the JGAP core will invoke this method on each Gene in the sample Chromosome in order to create each new Gene in the same respective gene position for a new Chromosome.

It should be noted that nothing is guaranteed about the actual value of the returned Gene and it should therefore be considered to be undefined.

Specified by:

newGene in interface Gene

Returns:

A new Gene instance of the same type and with the same setup as this concrete Gene.

setAllele

public void setAllele(java.lang.Object a_newValue)

Sets the value of this Gene to the new given value. This class expects the value to be a Boolean instance.

Specified by:

setAllele in interface Gene

Parameters:

a_newValue - the new value of this Gene instance.

getPersistentRepresentation

public java.lang.String getPersistentRepresentation()
                                             throws java.lang.UnsupportedOperationException

Retrieves a string representation of this Gene that includes any information required to reconstruct it at a later time, such as its value and internal state. This string will be used to represent this Gene in XML persistence. This is an optional method but, if not implemented, XML persistence and possibly other features will not be available. An UnsupportedOperationException should be thrown if no implementation is provided.

Specified by:

getPersistentRepresentation in interface Gene

Returns:

A string representation of this Gene's current state.

Throws:

java.lang.UnsupportedOperationException - to indicate that no implementation is provided for this method.

setValueFromPersistentRepresentation

public void setValueFromPersistentRepresentation(java.lang.String a_representation)
                                          throws UnsupportedRepresentationException

Sets the value and internal state of this Gene from the string representation returned by a previous invocation of the getPersistentRepresentation() method. This is an optional method but, if not implemented, XML persistence and possibly other features will not be available. An UnsupportedOperationException should be thrown if no implementation is provided.

Specified by:

setValueFromPersistentRepresentation in interface Gene

Parameters:

a_representation - the string representation retrieved from a prior call to the getPersistentRepresentation() method.

Throws:

java.lang.UnsupportedOperationException - to indicate that no implementation is provided for this method.

UnsupportedRepresentationException - if this Gene implementation does not support the given string representation.

Since:

1.0

getAllele

public java.lang.Object getAllele()

Retrieves the value represented by this Gene. All values returned by this class will be Boolean instances.

Specified by:

getAllele in interface Gene

Returns:

the Boolean value of this Gene.

booleanValue

public boolean booleanValue()

Retrieves the boolean value of this Gene. This may be more convenient in some cases than the more general getAllele() method.

Returns:

the boolean value of this Gene.

setToRandomValue

public void setToRandomValue(RandomGenerator a_numberGenerator)

Sets the value (allele) of this Gene to a random legal value. This method exists for the benefit of mutation and other operations that simply desire to randomize the value of a gene.

NOTE: Since this Gene implementation only supports two different values (true and false), there's only a 50% chance that invocation of this method will actually change the value of this Gene (if it has a value). As a result, it may be desirable to use a higher overall mutation rate when this Gene implementation is in use.

Specified by:

setToRandomValue in interface Gene

Parameters:

a_numberGenerator - The random number generator that should be used to create any random values. It's important to use this generator to maintain the user's flexibility to configure the genetic engine to use the random number generator of their choice.

compareTo

public int compareTo(java.lang.Object other)

Compares this BooleanGene with the specified object for order. A false value is considered to be less than a true value. A null value is considered to be less than any non-null value.

Specified by:

compareTo in interface java.lang.Comparable

Parameters:

other - the BooleanGene to be compared.

Returns:

a negative integer, zero, or a positive integer as this object is less than, equal to, or greater than the specified object.

Throws:

java.lang.ClassCastException - if the specified object's type prevents it from being compared to this BooleanGene.

Since:

1.0

equals

public boolean equals(java.lang.Object other)

Compares this BooleanGene with the given object and returns true if the other object is a BooleanGene and has the same value as this BooleanGene. Otherwise it returns false.

Parameters:

other - the object to compare to this BooleanGene for equality.

Returns:

true if this BooleanGene is equal to the given object, false otherwise.

hashCode

public int hashCode()

Retrieves the hash code value of this BooleanGene.

Returns:

this BooleanGene's hash code.

Since:

1.0

toString

public java.lang.String toString()

Retrieves a string representation of this BooleanGene's value that may be useful for display purposes.

Specified by:

toString in interface Gene

Returns:

a string representation of this BooleanGene's value.

Since:

1.1

cleanup

public void cleanup()

Executed by the genetic engine when this Gene instance is no longer needed and should perform any necessary resource cleanup.

Specified by:

cleanup in interface Gene

Since:

1.0

size

public int size()

Specified by:

size in interface Gene

Returns:

the size of the gene, i.e the number of atomic elements. Always 1 for BooleanGene

Since:

1.0

applyMutation

public void applyMutation(int index,
                          double a_percentage)

Applies a mutation of a given intensity (percentage) onto the atomic element at given index

Specified by:

applyMutation in interface Gene

Parameters:

index - index of atomic element, between 0 and size()-1

a_percentage - percentage of mutation (greater than -1 and smaller than 1).

Since:

1.1