org.pentaho.reporting.libraries.formula.lvalues
Class FormulaFunction

java.lang.Object
  org.pentaho.reporting.libraries.formula.lvalues.AbstractLValue
      org.pentaho.reporting.libraries.formula.lvalues.FormulaFunction

All Implemented Interfaces:

java.io.Serializable, java.lang.Cloneable, LValue

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

See Also:

Serialized Form

Constructor Summary

FormulaFunction(java.lang.String functionName, LValue[] parameters)

FormulaFunction(java.lang.String functionName, LValue[] parameters, ParsePosition parsePosition)

Method Summary

java.lang.Object	clone()
TypeValuePair	evaluate()
LValue[]	getChildValues() Returns any dependent lvalues (parameters and operands, mostly).
Function	getFunction() Returns the initialized function.
java.lang.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.
java.lang.String	toString()

Methods inherited from class org.pentaho.reporting.libraries.formula.lvalues.AbstractLValue

getContext, getParsePosition, getValueType, setParsePosition

Methods inherited from class java.lang.Object

equals, getClass, hashCode, notify, notifyAll, wait, wait, wait

Constructor Detail

FormulaFunction

public FormulaFunction(java.lang.String functionName,
                       LValue[] parameters,
                       ParsePosition parsePosition)

FormulaFunction

public FormulaFunction(java.lang.String functionName,
                       LValue[] parameters)

Method Detail

initialize

public void initialize(FormulaContext context)
                throws EvaluationException

Specified by:

initialize in interface LValue

Overrides:

initialize in class AbstractLValue

Throws:

EvaluationException

getFunctionName

public java.lang.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.

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.

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.

clone

public java.lang.Object clone()
                       throws java.lang.CloneNotSupportedException

Specified by:

clone in interface LValue

Overrides:

clone in class AbstractLValue

Throws:

java.lang.CloneNotSupportedException

evaluate

public TypeValuePair evaluate()
                       throws EvaluationException

Throws:

EvaluationException

getChildValues

public LValue[] getChildValues()

Returns any dependent lvalues (parameters and operands, mostly).

Specified by:

getChildValues in interface LValue

Overrides:

getChildValues in class AbstractLValue

Returns:

toString

public java.lang.String toString()

Overrides:

toString in class java.lang.Object

isConstant

public boolean isConstant()

Checks whether the LValue is constant. Constant lvalues always return the same value.

Returns:

true, if the function will always return the same value.