com.bayesserver

Class Variable

java.lang.Object

com.bayesserver.Variable

All Implemented Interfaces:

Cloneable, Comparable<Variable>

public final class Variable
extends Object
implements Comparable<Variable>, Cloneable

Represents a discrete or continuous random variable. Note that variable names must be unique per network, and are case sensitive.

A Node in a Bayesian network can contain one or more variables.

Although a discrete variable can contain a different number of states, a continuous variable always contains a single state.

Constructor Summary

Constructors

Constructor and Description
Variable() Initializes a new instance of the Variable class, with VariableValueType discrete and zero states.
Variable(String name) Initializes a new instance of the Variable class, with VariableValueType discrete, zero states, and the specified name.
Variable(String name, int states) Initializes a new instance of the Variable class, with VariableValueType discrete and the specified [name] and adds the number of states specified in [states].
Variable(String name, State... states) Initializes a new instance of the Variable class, with VariableValueType discrete and the specified name and adds the states specified in [states].
Variable(String name, String[] states) Initializes a new instance of the Variable class, with VariableValueType discrete and the specified name and adds the states specified in [states].
Variable(String name, VariableValueType valueType) Initializes a new instance of the Variable class with the specified name and value type.
Variable(String name, VariableValueType valueType, VariableKind kind) Initializes a new instance of the Variable class with the specified name, kind and value type.

Method Summary

Modifier and Type	Method and Description
int	compareTo(Variable other)
Variable	copy() Copies this instance.
State	findStateByValue(Object value) Finds a state based on a state value.
CustomPropertyCollection	getCustomProperties() Gets custom properties associated with this instance.
String	getDescription() An optional description for the variable.
String	getExpressionAlias() Gets a c-style name for a variable that can be used as an alias in expressions.
QueryExpression	getFunction() Gets an expression, which is evaluated during a query, and can be based on other queries and expressions.
int	getIndex() The Index of this instance in the collection of variables belonging to a network, or -1 if the variable does not belong to a node and hence a network.
VariableKind	getKind() Gets the kind of variable, such as Probability, Decision, Utility or Function.
String	getName() Gets the name of the variable.
Node	getNode() Gets the Node this instance belongs to, if any.
StateCollection	getStates() Returns the collection of states belonging to the variable.
StateValueType	getStateValueType() Gets the type of value that states belonging to this variable can represent.
VariableValueType	getValueType() Gets the variable's value type, e.g.
void	setDescription(String value) An optional description for the variable.
void	setExpressionAlias(String value) Sets a c-style name for a variable that can be used as an alias in expressions.
void	setFunction(QueryExpression value) Sets an expression, which is evaluated during a query, and can be based on other queries and expressions.
void	setName(String value) Sets the name of the variable.
void	setStateValueType(StateValueType value) Sets the type of value that states belonging to this variable can represent.
String	toString() Returns the name of the variable, or an empty string if the name is null.

Methods inherited from class java.lang.Object

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

Constructor Detail

Variable

public Variable()

Initializes a new instance of the Variable class, with VariableValueType discrete and zero states.

Variable

public Variable(String name)

Initializes a new instance of the Variable class, with VariableValueType discrete, zero states, and the specified name.

Parameters:

name - The name of the variable. Can be null.

Variable

public Variable(String name,
                VariableValueType valueType,
                VariableKind kind)

Initializes a new instance of the Variable class with the specified name, kind and value type. If discrete, no states are added.

Parameters:

name - The name of the variable. Can be null.

valueType - The value type, e.g. continuous or discrete.

kind - The kind of Variable, e.g. Probability, Decision or Utility.

Variable

public Variable(String name,
                VariableValueType valueType)

Initializes a new instance of the Variable class with the specified name and value type. If discrete, no states are added.

Parameters:

name - The name of the variable. Can be null.

valueType - The value type, e.g. continuous or discrete.

Variable

public Variable(String name,
                int states)

Initializes a new instance of the Variable class, with VariableValueType discrete and the specified [name] and adds the number of states specified in [states].

Parameters:

name - The name to give the Variable, which can be null or empty.

states - The number of states to add to the Variable. States will be given default names.

Throws:

IllegalArgumentException - Raised when the [states] parameter is less than zero.

Variable

public Variable(String name,
                String[] states)

Initializes a new instance of the Variable class, with VariableValueType discrete and the specified name and adds the states specified in [states].

Parameters:

name - The name of the node and variable.

states - The states to add to the associated Variable, specified by their names.

Throws:

NullPointerException - Raised when [states] is null.

IllegalArgumentException - Raised when the names in [states] are not unique, or are null or empty.

Variable

public Variable(String name,
                State... states)

Initializes a new instance of the Variable class, with VariableValueType discrete and the specified name and adds the states specified in [states].

Parameters:

name - The name of the node and variable.

states - The states to add to the associated Variable.

Throws:

NullPointerException - Raised when [states] is null.

IllegalArgumentException - Raised when the names in [states] are not unique, or are null or empty.

Method Detail

findStateByValue

public State findStateByValue(Object value)

Finds a state based on a state value. E.g. finds the state who's interval contains the supplied value, or who's integer state value matches the supplied integer.

Parameters:

value - The value to test against state values. Type will depend on StateValueType. e.g. pass a double if the state value type is a double interval.

Returns:

The matching state or null.

compareTo

public int compareTo(Variable other)

Specified by:

compareTo in interface Comparable<Variable>

getStateValueType

public StateValueType getStateValueType()

Gets the type of value that states belonging to this variable can represent. For example an interval.

setStateValueType

public void setStateValueType(StateValueType value)

Sets the type of value that states belonging to this variable can represent. For example an interval.

copy

public Variable copy()

Copies this instance.

Returns:

A new Variable instance.

getCustomProperties

public CustomPropertyCollection getCustomProperties()

Gets custom properties associated with this instance. Custom properties allow storage of custom information, which will be saved with the network.

getDescription

public String getDescription()

An optional description for the variable.

setDescription

public void setDescription(String value)

An optional description for the variable.

getFunction

public QueryExpression getFunction()

Gets an expression, which is evaluated during a query, and can be based on other queries and expressions.

setFunction

public void setFunction(QueryExpression value)

Sets an expression, which is evaluated during a query, and can be based on other queries and expressions.

getValueType

public VariableValueType getValueType()

Gets the variable's value type, e.g. continuous or discrete.

Returns:

The variable's value type.

getKind

public VariableKind getKind()

Gets the kind of variable, such as Probability, Decision, Utility or Function.

getStates

public StateCollection getStates()

Returns the collection of states belonging to the variable. Continuous variables always have a single state.

See Also:

State

toString

public String toString()

Returns the name of the variable, or an empty string if the name is null.

Overrides:

toString in class Object

Returns:

A String containing the name of the variable which is empty if the name is null.

getNode

public Node getNode()

Gets the Node this instance belongs to, if any.

Returns:

The node the instance belongs to, if any.

getExpressionAlias

public String getExpressionAlias()

Gets a c-style name for a variable that can be used as an alias in expressions.

setExpressionAlias

public void setExpressionAlias(String value)

Sets a c-style name for a variable that can be used as an alias in expressions.

getName

public String getName()

Gets the name of the variable. When a variable is added to a network, its name must be unique. Comparisons are case sensitive.

setName

public void setName(String value)

Sets the name of the variable. When a variable is added to a network, its name must be unique. Comparisons are case sensitive.

getIndex

public int getIndex()

The Index of this instance in the collection of variables belonging to a network, or -1 if the variable does not belong to a node and hence a network.