org.jfree.formula.lvalues

Class FormulaFunction

Implemented Interfaces:
Cloneable, LValue, Serializable

public class FormulaFunction
extends AbstractLValue

A function. Formulas consist of functions, references or static values, which are connected by operators.

Functions always have a cannonical name, which must be unique and which identifies the function. Functions can have a list of parameters. The number of parameters can vary, and not all parameters need to be filled.

Functions can have required and optional parameters. Mixing required and optional parameters is not allowed. Optional parameters cannot be ommited, unless they are the last parameter in the list.

This class provides the necessary wrapper functionality to fill in the parameters.

Author:
Thomas Morgner

Constructor Summary

FormulaFunction(String functionName, LValue[] parameters)

Method Summary

Object
clone()
TypeValuePair
evaluate()
LValue[]
getChildValues()
Returns any dependent lvalues (parameters and operands, mostly).
Function
getFunction()
Returns the initialized function.
String
getFunctionName()
Returns the function's name.
FunctionDescription
getMetaData()
Returns the function's meta-data.
void
initialize(FormulaContext context)
boolean
isConstant()
Checks, whether the LValue is constant.
String
toString()

Methods inherited from class org.jfree.formula.lvalues.AbstractLValue

clone, getChildValues, getContext, getValueType, initialize

Constructor Details

FormulaFunction

public FormulaFunction(String functionName,
                       LValue[] parameters)

Method Details

clone

public Object clone()
            throws CloneNotSupportedException
Specified by:
clone in interface LValue
Overrides:
clone in interface AbstractLValue

evaluate

public TypeValuePair evaluate()
            throws EvaluationException
Specified by:
evaluate in interface LValue

getChildValues

public LValue[] getChildValues()
Returns any dependent lvalues (parameters and operands, mostly).
Specified by:
getChildValues in interface LValue
Overrides:
getChildValues in interface AbstractLValue
Returns:

getFunction

public Function getFunction()
Returns the initialized function. Be aware that this method will return null if this LValue instance has not yet been initialized.
Returns:
the function instance or null, if the FormulaFunction instance has not yet been initialized.

getFunctionName

public String getFunctionName()
Returns the function's name. This is the normalized name and may not be suitable for the user. Query the function's metadata to retrieve a display-name.
Returns:
the function's name.

getMetaData

public FunctionDescription getMetaData()
Returns the function's meta-data. Be aware that this method will return null if this LValue instance has not yet been initialized.
Returns:
the function description instance or null, if the FormulaFunction instance has not yet been initialized.

initialize

public void initialize(FormulaContext context)
            throws EvaluationException
Specified by:
initialize in interface LValue
Overrides:
initialize in interface AbstractLValue

isConstant

public boolean isConstant()
Checks, whether the LValue is constant. Constant lvalues always return the same value.
Specified by:
isConstant in interface LValue
Returns:

toString

public String toString()