com.klg.jclass.util.formulae
Class ExpressionVariable

java.lang.Object
  |
  +--com.klg.jclass.util.formulae.ExpressionVariable

All Implemented Interfaces:

Cloneable, Expression

public class ExpressionVariable

extends Object

implements Expression, Cloneable

A variable is a named expression which can have its value changed by name-keyed access to it.

Field Summary

protected Object	context The context in which the variable is defined
protected String	name The name by which the variable is known and referred to
protected com.klg.jclass.util.formulae.Expression	value The value which the variable is currently assigned
protected static HashMap	variableMap The variable map stores all named variables (disambiguated by context)

Method Summary

Object	clone() Clone this variable; since variables are unique to a context, we return the variable itself.
static com.klg.jclass.util.formulae.ExpressionVariable	createVariable(Object context, String name) Create a variable Expression given a context and name
boolean	equals(Object obj) Determine if this variable matches another
com.klg.jclass.util.formulae.Result	evaluate() As an Expression, the evaluation of this variable is its stored value (or the evaluation of a stored Expression).
com.klg.jclass.util.formulae.Expression	getValue() Retrieve the Expression which is stored by this Variable
static com.klg.jclass.util.formulae.ExpressionVariable	getVariable(Object context, String name) Retrieve a variable Expression given a context and name
int	hashCode() Compute the hashcode for this variable based on the context and name
void	setValue(com.klg.jclass.util.formulae.Expression value) Set the current value of a variable
static com.klg.jclass.util.formulae.ExpressionVariable	setVariable(Object context, String name, com.klg.jclass.util.formulae.Expression value) Create or set a variable Expression given a context, name and value

Methods inherited from class java.lang.Object

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

Field Detail

name

protected String name

The name by which the variable is known and referred to

context

protected Object context

The context in which the variable is defined

value

protected com.klg.jclass.util.formulae.Expression value

The value which the variable is currently assigned

variableMap

protected static HashMap variableMap

The variable map stores all named variables (disambiguated by context)

Method Detail

createVariable

public static com.klg.jclass.util.formulae.ExpressionVariable createVariable(Object context,
                                                                             String name)

Create a variable Expression given a context and name

Parameters:

context - The object in which context the name is unique

name - The name of the variable

setVariable

public static com.klg.jclass.util.formulae.ExpressionVariable setVariable(Object context,
                                                                          String name,
                                                                          com.klg.jclass.util.formulae.Expression value)

Create or set a variable Expression given a context, name and value

Parameters:

context - The object in which context the name is unique

name - The name of the variable

value - The current value of the variable

getVariable

public static com.klg.jclass.util.formulae.ExpressionVariable getVariable(Object context,
                                                                          String name)

Retrieve a variable Expression given a context and name

Parameters:

context - The object in which context the name is unique

name - The name of the variable

evaluate

public com.klg.jclass.util.formulae.Result evaluate()

As an Expression, the evaluation of this variable is its stored value (or the evaluation of a stored Expression).

Specified by:

evaluate in interface Expression

Returns:

The Result of the stored Expression

setValue

public void setValue(com.klg.jclass.util.formulae.Expression value)

Set the current value of a variable

Parameters:

value - The new value the variable will have

getValue

public com.klg.jclass.util.formulae.Expression getValue()

Retrieve the Expression which is stored by this Variable

Returns:

The unevaluated Expression this variable is equal to

hashCode

public int hashCode()

Compute the hashcode for this variable based on the context and name

Overrides:

hashCode in class Object

Returns:

A hash of the context and name values of this variable

equals

public boolean equals(Object obj)

Determine if this variable matches another

Overrides:

equals in class Object

Parameters:

obj - The object to test for equality

Returns:

True if the variables have the same name and context

clone

public Object clone()

Clone this variable; since variables are unique to a context, we return the variable itself.

Specified by:

clone in interface Expression

Overrides:

clone in class Object