com.numobjects.mathbeans.awt
Class CalcGraphPanel

com.numobjects.mathbeans.awt.CalcGraphPanel

public class CalcGraphPanel

implements java.io.Serializable

Class CalcGraphPanel (Calculator graph panel bean) provides the following functionality: based solely on a string representing a set of several mathematical expressions with any number of variables, automatically constructs and displays a mini-calculator and graph panel for this expression. The mini-calculator panel is a CalcPanel bean. It provides the possibility to calculate the results according to the formulas. The graph panel lets the user plot any of the result as a function of any of its variables. For this purpose there is a graph parameter panel containing the Plot and Print buttons, choices for the function and independent variable and fields for specifying the range of the independent variable. This bean provides a unique possibility of creating various calculators, static or dynamic, avoiding the hassle of setting up GUI, adding logic, dispatching events, actual plotting, etc., etc. The user's only input is the set of formulas 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 name to consist of several words, use quotes around the name in the formula. 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 panel would contain six fields labeled "Quantity", "Item price", "Tax rate", "Shipping", "Total tax" and "Total amount". As soon as one enters values in the first four fields and presses Enter, the fields "Total tax" and "Total amount" will display the computed values. Missing values are treated as zero.

The graph parameter panel would contain the variable names "Quantity", "Item price", "Tax rate" and "Shipping" in the choice. It would also contain fields for entering the independent variable range. To plot the graph, enter the required values, choose the dependent and independent variables and press the Plot button. On the calculator panel, the field corresponding to the chosen independent variable may contain anything as well as be blank. The fields for the other variables must contain values. If a field is blank, the value is assumed to be zero.

The graph panel is initially blank. After the graph is plotted it would display also the X and Y axes if they fall within the graph range, and marks for measurements in the X and Y directions. Also, an info string is shown. It indicates the scaling used for X and Y, and the ratio between the displayed measurements in the X and Y direction. Another optional information describing the dependencies is shown at the bottom. After the graph is plotted, the Print button gets enabled, and the graph can be printed.

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

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

The calculator graph panel is ready to be added to your container.

The parameter entry fields can be any subclasses of java.awt.TextField, but the default entry fields are in fact CalcFields, so it is safe to cast them to this type if desired as well as use them to compute constant expressions. The panel is dynamically resizable with the automatic adjustment of the graph. It can also be rolled up to a usual CalcPanel and extended to its full form by pressing a single (+/-) button. If such resizing occurs, the parent of the panel is notified of the componentResized event (with null ComponentEvent), so it can adjust its size accordingly.

The new feature in version 2 is the ability to support several formulas.

See Also:

CalcField, CalcPanel, Serialized Form

Constructor Summary

CalcGraphPanel()
Constructor

Method Summary

int	getFieldHeight() Gets entry field height
int	getFieldWidth() Gets entry field width
java.lang.String	getFormulae() Gets formulae for the panel
int	getGMargin() Gets margin for the graph panel (vertical space between the graph itself and the graph display area)
int	getHMargin() Gets horizontal margin for the graph panel
int	getHorizontalSpacing() Gets horizontal spacing between fields
java.awt.Insets	getInsets() Gets insets
java.awt.Dimension	getMinimumSize() Gets minimal size for the panel
java.awt.TextField	getParameterField(java.lang.String parameterName) Gets parameter entry field for given parameter name
int	getPrecision() Gets precision
java.awt.TextField	getResultField(java.lang.String resultName) Gets field for the result
java.lang.String	getResultName(int index) Gets name (label) for the result field
java.lang.String[]	getResultNames() Gets names (labels) for the result fields
int	getRounding() Gets rounding
int	getVerticalSpacing() Gets vertical spacing between fields
int	getVMargin() Gets vertical margin for the graph panel
boolean	isDisplayInfo() Gets info display flag
boolean	isDisplayLogo() Gets logo display flag
boolean	isExtended() Gets extended view flag (whether the graph panel is visible)
void	paint(java.awt.Graphics g) Paints the panel
void	setBackground(java.awt.Color c) Sets background
void	setDisplayInfo(boolean flag) Sets info display flag
void	setDisplayLogo(boolean flag) Sets logo display flag
void	setExtended(boolean flag) Sets extended view of the panel (to include the graph panel)
void	setFieldHeight(int value) Sets entry field height
void	setFieldWidth(int value) Sets entry field width
void	setFormulae(java.lang.String formulae) Sets formulae
void	setGMargin(int value) Sets margin for the graph panel (vertical space between the graph itself and the graph display area)
void	setHMargin(int value) Sets horizontal margin for the graph panel
void	setHorizontalSpacing(int value) Sets horizontal spacing
void	setInsets(java.awt.Insets insets) Sets insets for the panel
void	setParameterField(java.lang.String parameterName, java.awt.TextField field) Tags a text field as a parameter field for given parameter name
void	setPrecision(int value) Sets precision (the number of significant digits in the calculation); range 1 - 15, default precision is 6
void	setResultField(java.lang.String resultName, java.awt.TextField field) Tags a text field as the result field
void	setResultNames(java.lang.String[] names) Sets result labels
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	setVerticalSpacing(int value) Sets vertical spacing
void	setVMargin(int value) Sets vertical margin for the graph panel

Constructor Detail

CalcGraphPanel

public CalcGraphPanel()

Constructor

Method Detail

getFormulae

public java.lang.String getFormulae()

Gets formulae for the panel

Returns:

formulae

setFormulae

public void setFormulae(java.lang.String formulae)

Sets formulae

Parameters:

formulae - formulae string

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)

setInsets

public void setInsets(java.awt.Insets insets)

Sets insets for the panel

Parameters:

insets - insets

getInsets

public java.awt.Insets getInsets()

Gets insets

Returns:

insets

setVerticalSpacing

public void setVerticalSpacing(int value)

Sets vertical spacing

Parameters:

value - value to set

getVerticalSpacing

public int getVerticalSpacing()

Gets vertical spacing between fields

Returns:

vertical spacing

setHorizontalSpacing

public void setHorizontalSpacing(int value)

Sets horizontal spacing

Parameters:

value - value to set

getHorizontalSpacing

public int getHorizontalSpacing()

Gets horizontal spacing between fields

Returns:

horizontal spacing

setFieldWidth

public void setFieldWidth(int value)

Sets entry field width

Parameters:

value - value to set

getFieldWidth

public int getFieldWidth()

Gets entry field width

Returns:

field width

setFieldHeight

public void setFieldHeight(int value)

Sets entry field height

Parameters:

value - value to set

getFieldHeight

public int getFieldHeight()

Gets entry field height

Returns:

field height

setDisplayLogo

public void setDisplayLogo(boolean flag)

Sets logo display flag

Parameters:

flag - value to set

isDisplayLogo

public boolean isDisplayLogo()

Gets logo display flag

Returns:

logo flag

setDisplayInfo

public void setDisplayInfo(boolean flag)

Sets info display flag

Parameters:

flag - value to set

isDisplayInfo

public boolean isDisplayInfo()

Gets info display flag

Returns:

info flag

setHMargin

public void setHMargin(int value)

Sets horizontal margin for the graph panel

Parameters:

value - value to set

getHMargin

public int getHMargin()

Gets horizontal margin for the graph panel

Returns:

margin value

setVMargin

public void setVMargin(int value)

Sets vertical margin for the graph panel

Parameters:

value - value to set

getVMargin

public int getVMargin()

Gets vertical margin for the graph panel

Returns:

margin value

setGMargin

public void setGMargin(int value)

Sets margin for the graph panel (vertical space between the graph itself and the graph display area)

Parameters:

value - value to set

getGMargin

public int getGMargin()

Gets margin for the graph panel (vertical space between the graph itself and the graph display area)

Returns:

margin value

setResultNames

public void setResultNames(java.lang.String[] names)

Sets result labels

Parameters:

names - result names to set

getResultNames

public java.lang.String[] getResultNames()

Gets names (labels) for the result fields

Returns:

result label names

getResultName

public java.lang.String getResultName(int index)

Gets name (label) for the result field

Returns:

result label name

setParameterField

public void setParameterField(java.lang.String parameterName,
                              java.awt.TextField field)

Tags a text field as a parameter field for given parameter name

Parameters:

parameterName - parameter name

field - text field to tag

getParameterField

public java.awt.TextField getParameterField(java.lang.String parameterName)

Gets parameter entry field for given parameter name

Parameters:

parameterName - parameter name

Returns:

parameter field

setResultField

public void setResultField(java.lang.String resultName,
                           java.awt.TextField field)

Tags a text field as the result field

Parameters:

field - text field to tag

getResultField

public java.awt.TextField getResultField(java.lang.String resultName)

Gets field for the result

Returns:

result field

setExtended

public void setExtended(boolean flag)

Sets extended view of the panel (to include the graph panel)

Parameters:

flag - extended flag

isExtended

public boolean isExtended()

Gets extended view flag (whether the graph panel is visible)

Returns:

extended view flag

paint

public void paint(java.awt.Graphics g)

Paints the panel

Parameters:

g - graphics

getMinimumSize

public java.awt.Dimension getMinimumSize()

Gets minimal size for the panel

Returns:

minimal size

setBackground

public void setBackground(java.awt.Color c)

Sets background

Parameters:

c - color