com.numobjects.mathbeans
Class CalcSet

com.numobjects.mathbeans.CalcSet

public class CalcSet

implements java.io.Serializable, java.awt.event.ActionListener

Class CalcSet (Calculator set bean) provides the following functionality: based solely on a string representing a set of mathematical expressions with any number of variables, automatically constructs and displays a mini-calculator panel for these expressions. The panel will have named input fields for all variables in the expressions and similar fields for the results. The user enters any numbers into the input fields and presses a button or just Enter in any of these fields. The result is immediately computed and displayed in the result fields. The user can set parameters that control the format of the output.

This bean provides a unique possibility of creating various calculators, static or dynamic, avoiding the hassle of setting up GUI, adding logic, dispatching events, etc. The user's only input is the formula itself, all the rest is figured out by the bean.

The formulas must have the form

Result1=expression1;...ResultN=expressionN

Here "ResultX" is any string providing the name for the result, e.g. "Total amount". The "expressionX" must be a valid non-constant mathematical expression (i.e. must contain variables). Variable names in the expression cannot contain spaces; if there is a need for the displayed screen name to consist of several words, enclose the name in double quotes. Here is one simple example:

"Total tax"=Quantity*"Item price"*"Tax rate"/100;
"Total amount"=Quantity*"Item price"*(1+"Tax rate"/100)+Shipping

The resulting calculator set would contain a parameter panel with fields labeled "Quantity", "Item price", "Tax rate", "Shipping", and a result panel with "Total tax" and "Total amount". As soon as one enters values in the first four fields and presses Enter, the result fields will display the computed values. Missing values are treated as zero.

Here is the code that you have to include in your program:

import com.numobjects.mathbeans.CalcSet;
...
String formula = "Total tax=Quantity*\"Item price\"*\"Tax rate\"/100;Total amount=Quantity*\"Item price\"*(1+\"Tax rate\"/100)+Shipping";
CalcSet calcSet = new CalcSet ();
calcSet.setFormulae (formula);

The calculator set is ready to be added to your container.

See Expression syntax and available functions for a full description of syntax, available functions and procedures.

See Also:

CalcSolveSet, CalcGraphSet, Serialized Form

Constructor Summary

CalcSet()
Constructs new CalcPanel

Method Summary

void	actionPerformed(java.awt.event.ActionEvent e) Responds to action events
void	addActionListener(java.awt.event.ActionListener l) Adds action listener
com.numobjects.beans.ControlPanel	getControl() Gets control panel
java.lang.String	getFormulae() Gets the formula set for the calc set
NamedFieldPanel	getParameterPanel() Gets the parameter panel
int	getParametersCount() Gets the number of parameters of a set of formulas
int	getParametersDisplayCount() Gets the number of parameters of a set of formulas
java.lang.String[]	getParameterTitles() Gets panel titles for the parameter panel
java.lang.String	getParameterTitles(int i) Gets panel title for the parameter panel
int	getPrecision() Gets precision
NamedFieldPanel	getResultPanel() Gets the result panel
int	getResultsCount() Gets the number of formulas in a set
int	getResultsDisplayCount() Gets the number of formulas in a set
java.lang.String[]	getResultTitles() Gets panel titles for the result panel
java.lang.String	getResultTitles(int i) Gets panel title for the result panel
java.lang.String	getResultValue(int index) Gets value of a formula
int	getRounding() Gets rounding
java.lang.String	getValue(java.lang.String parameterName) Gets value of a parameter.
void	removeActionListener(java.awt.event.ActionListener l) Removes action listener
void	setBackground(java.awt.Color c) Sets background color
void	setControl(com.numobjects.beans.ControlPanel control) Sets control panel
void	setFormulae(java.lang.String formulaSet) Sets formulae
void	setParameterError(java.lang.String parameterName) Sets parameter error for a parameter
void	setParameterError(java.lang.String parameterName, boolean flag) Sets parameter error for a parameter
void	setParameterPanel(NamedFieldPanel panel) Sets the parameter panel
void	setParameterTitles(int i, java.lang.String title) Sets panel title for the parameter panel
void	setParameterTitles(java.lang.String[] titles) Sets panel titles for the parameter panel
void	setPrecision(int value) Sets precision (the number of significant digits in the calculation); range 1 - 15, default precision is 6
void	setResultPanel(NamedFieldPanel panel) Sets the result panel
void	setResultTitles(int i, java.lang.String title) Sets panel title for the result panel
void	setResultTitles(java.lang.String[] titles) Sets panel titles for the result panel
void	setResultValue(int index, java.lang.String result) Sets result value for a given formula in a set
void	setRounding(int value) Sets rounding (the number of digits displayed after the decimal dot); range -1 - 15, default rounding is -1 (no rounding)
void	updateSet()

Constructor Detail

CalcSet

public CalcSet()

Constructs new CalcPanel

Method Detail

getParameterTitles

public java.lang.String[] getParameterTitles()

Gets panel titles for the parameter panel

Returns:

titles

getParameterTitles

public java.lang.String getParameterTitles(int i)

Gets panel title for the parameter panel

Parameters:

i - title index

Returns:

titles

setParameterTitles

public void setParameterTitles(int i,
                               java.lang.String title)

Sets panel title for the parameter panel

Parameters:

i - title index

title - title (string)

setParameterTitles

public void setParameterTitles(java.lang.String[] titles)

Sets panel titles for the parameter panel

Parameters:

titles - titles

getResultTitles

public java.lang.String[] getResultTitles()

Gets panel titles for the result panel

Returns:

titles

getResultTitles

public java.lang.String getResultTitles(int i)

Gets panel title for the result panel

Parameters:

i - title index

Returns:

titles

setResultTitles

public void setResultTitles(int i,
                            java.lang.String title)

Sets panel title for the result panel

Parameters:

i - title index

title - title (string)

setResultTitles

public void setResultTitles(java.lang.String[] titles)

Sets panel titles for the result panel

Parameters:

titles - titles

setBackground

public void setBackground(java.awt.Color c)

Sets background color

Parameters:

c - color

setPrecision

public void setPrecision(int value)

Sets precision (the number of significant digits in the calculation); range 1 - 15, default precision is 6

Parameters:

value - precision to set

getPrecision

public int getPrecision()

Gets precision

Returns:

precision value (the number of significant digits in the calculation)

setRounding

public void setRounding(int value)

Sets rounding (the number of digits displayed after the decimal dot); range -1 - 15, default rounding is -1 (no rounding)

Parameters:

value - rounding

getRounding

public int getRounding()

Gets rounding

Returns:

rounding value (the number of digits displayed after the decimal dot)

getParametersCount

public int getParametersCount()

Gets the number of parameters of a set of formulas

Returns:

number of parameters

getParametersDisplayCount

public int getParametersDisplayCount()

Gets the number of parameters of a set of formulas

Returns:

number of parameters

getResultsCount

public int getResultsCount()

Gets the number of formulas in a set

Returns:

number of formulas

getResultsDisplayCount

public int getResultsDisplayCount()

Gets the number of formulas in a set

Returns:

number of formulas

updateSet

public void updateSet()

setFormulae

public void setFormulae(java.lang.String formulaSet)

Sets formulae

Parameters:

formulaSet - a string representing a set of formulae (semicolon delimited)

getFormulae

public java.lang.String getFormulae()

Gets the formula set for the calc set

Returns:

formula set string

addActionListener

public void addActionListener(java.awt.event.ActionListener l)

Adds action listener

Parameters:

l - ActionListener

removeActionListener

public void removeActionListener(java.awt.event.ActionListener l)

Removes action listener

Parameters:

l - ActionListener

actionPerformed

public void actionPerformed(java.awt.event.ActionEvent e)

Responds to action events

Specified by:

actionPerformed in interface java.awt.event.ActionListener

Parameters:

e - ActionEvent

getValue

public java.lang.String getValue(java.lang.String parameterName)

Gets value of a parameter. If the value is not numeric, raises an error

Parameters:

parameterName - parameter name

Returns:

parameter value (represented as a string)

getResultValue

public java.lang.String getResultValue(int index)

Gets value of a formula

Parameters:

index - formula index in a set

Returns:

value (represented as a string)

setResultValue

public void setResultValue(int index,
                           java.lang.String result)

Sets result value for a given formula in a set

Parameters:

index - formula index

result - string value to set

setParameterError

public void setParameterError(java.lang.String parameterName)

Sets parameter error for a parameter

Parameters:

parameterName - parameter name

flag - error flag

setParameterError

public void setParameterError(java.lang.String parameterName,
                              boolean flag)

Sets parameter error for a parameter

Parameters:

parameterName - parameter name

flag - error flag

getParameterPanel

public NamedFieldPanel getParameterPanel()

Gets the parameter panel

Returns:

parameter panel

setParameterPanel

public void setParameterPanel(NamedFieldPanel panel)

Sets the parameter panel

Parameters:

panel - parameter panel

setResultPanel

public void setResultPanel(NamedFieldPanel panel)

Sets the result panel

Parameters:

panel - result panel

getResultPanel

public NamedFieldPanel getResultPanel()

Gets the result panel

Returns:

result panel

getControl

public com.numobjects.beans.ControlPanel getControl()

Gets control panel

Returns:

control panel

setControl

public void setControl(com.numobjects.beans.ControlPanel control)

Sets control panel

Parameters:

control - control panel