jscicalc.CalculatorPanel Class Reference

This class creates the main CalculatorPanel, which contains 44 buttons and a display panel (DisplayPanel object) to emulate an LCD display. More...

Inheritance diagram for jscicalc.CalculatorPanel:

Collaboration diagram for jscicalc.CalculatorPanel:

[legend]

List of all members.

Public Member Functions

synchronized void run ()

Required to implement Runnable interface.

synchronized void paintComponent (java.awt.Graphics graphics)

Paint the component: sets the colour for the background.

synchronized void layoutSprings ()

Long function that lays out buttons and DisplayPanel.

synchronized void setDisplayPanel ()

synchronized java.util.Vector
< CalculatorButton > buttons ()

CalculatorApplet might need this.

synchronized java.util.HashMap
< Character, CalculatorButton > keyMap ()

CalculatorApplet uses this to handle keyboard shortcuts.

Base base ()

I can’t rememeber why we have this.

void base (Base base)

I can’t rememeber why we have this.

Static Public Member Functions

static CalculatorPanel createPanel (CalculatorApplet applet, SpecialButtonType sbt, java.awt.Color colour)

We use this rather than a constructor to create a CalculatorPanel because in practice we always want a subclass.

Protected Member Functions

CalculatorPanel (CalculatorApplet applet, SpecialButtonType sbt, java.awt.Color colour)

Constructor is protected so that this class never actually gets instantiated.

abstract void setButtons ()

Subclasses implement this so that they can define all the standard buttons like Numeral, Add, etc.

void createKeyMap ()

The method that creates the keyMap.

Protected Attributes

java.awt.Color colour

Background colour.

final CalculatorApplet applet

We need to know the CalculatorApplet so we can assign it to buttons as we add them.

final SpecialButtonType sbt

used to identify panels, which are accessed through a CalculatorPanel pointer.

javax.swing.SpringLayout layout

The Layout.

java.util.Vector
< CalculatorButton > buttons

The list of buttons.

java.util.HashMap< Character,
CalculatorButton > keyMap

A map used by CalculatorApplet to fire Action events to buttons based on keyboard presses.

Private Member Functions

void setUp ()

Creates a key map for the CalculatorApplet, puts in nonstandard buttons, asks the subclass method to set the standard buttons, and arranges all buttons in a SpringLayout.

Private Attributes

Base base

A Base.

javax.swing.Spring xBorderSpring

A Spring.

javax.swing.Spring yBorderSpring

A Spring.

javax.swing.Spring strutX

A Spring.

javax.swing.Spring strutY

A Spring.

javax.swing.Spring minX

A Spring.

javax.swing.Spring minY

A Spring.

javax.swing.Spring buttonWidthSpring

A Spring.

javax.swing.Spring narrowButtonWidthSpring

A Spring.

javax.swing.Spring thinButtonWidthSpring

A Spring.

javax.swing.Spring buttonHeightSpring

A Spring.

javax.swing.Spring shortButtonHeightSpring

A Spring.

javax.swing.Spring shortButtonWidthSpring

A Spring.

javax.swing.Spring displayWidthSpring

A Spring.

javax.swing.Spring displayHeightSpring

A Spring.

Detailed Description

This class creates the main CalculatorPanel, which contains 44 buttons and a display panel (DisplayPanel object) to emulate an LCD display.

The panel needs to know about the controller CalculatorApplet because the controller creates the DisplayPanel and because each button must can ask the CalculatorApplet object to change state or add something to the expression stored in Parser.

The CalculatorPanel is the pane that sits inside the main frame or is the visible part of the applet.

In fact the calculator has more than 44 buttons. This creates an obvious problem: how to make all the buttons available without cluttering up the GUI in much the way that a real calculator does and without making the buttons small and unreadable.

The buttons are derived from CalculatorButton and use HTML to draw their text representation. This allows us to have very readable buttons that we can rescale. But it means we cannot redraw buttons instantly. So, the solution of redrawing buttons as needed in response to a press of the SHIFT button produces a noticeable slowdown in the calculator operation.

My solution is to have several CalculatorPanel objects, each derived from this class and to replace them as needed. This creates its own problem. We need to setup and draw six panels with nearly 350 buttons. Morevover the calculator should be extensible and allow the possibility of even more. The consequence of all this drawing is that the calculator would be quite slow to start up - nothing like as slow as starting M$ office - but enough to be noticeable and irritating.

There are several ways to get round this, not mutually incompatible. For example, you could use separate button panels so that not all buttons get replaced. But it suited me to use multithreading instead. The first panel available should be the PlainPanel object and it is created and added first. The remaining panels are created on a low priority thread. So, at least for simple calculations and switching on, the calculator starts reasonably quickly and, in particular, shows a visible GUI almost immediately after the frame appears.

To make the multithreading work, this calculator implements the Runnable interface.

See also:

CalculatorButton

CalculatorApplet

DisplayPanel

Author:: J. D. Lamb

Version:

Revision: 1.6

Constructor & Destructor Documentation

jscicalc.CalculatorPanel.CalculatorPanel	(	CalculatorApplet	applet,
		SpecialButtonType	sbt,
		java.awt.Color	colour
	)			`[protected]`

Constructor is protected so that this class never actually gets instantiated.

Parameters:

	applet	Needed so that buttons can call the controller
	sbt	Stored so that we can identify the subclass
	colour	The background colour.

References jscicalc.CalculatorPanel.colour.

Member Function Documentation

static CalculatorPanel jscicalc.CalculatorPanel.createPanel	(	CalculatorApplet	applet,
		SpecialButtonType	sbt,
		java.awt.Color	colour
	)			`[static]`

We use this rather than a constructor to create a CalculatorPanel because in practice we always want a subclass.

We supply the CalculatorApplet object and a SpecialButtonType used to identify which subclass we want. We also pass a colour. Conceivably different panels could have different colours, though it might be better to get each to ask CalculatorApplet for its colour.

If sbt is SpecialButtonType.NONE then the CalculatorPanel is a PlainPanel and is created now. Otherwise it is created in a background thread.

Parameters:

	applet	The CalculatorApplet object needed for the buttons and DisplayPanel
	sbt	Used to identify what to construct
	colour	What colour should the panel background be?

See also:: CalculatorApplet
SpecialButtonType

References jscicalc.CalculatorPanel.colour, jscicalc.HEX, jscicalc.NONE, jscicalc.CalculatorPanel.run(), jscicalc.SHIFT, jscicalc.SHIFT_HEX, jscicalc.SHIFT_STAT, and jscicalc.STAT.

Referenced by jscicalc.CalculatorApplet.setPanels().

synchronized void jscicalc.CalculatorPanel.run ( )

Required to implement Runnable interface.

Calls setUp().

References jscicalc.CalculatorPanel.setUp().

Referenced by jscicalc.CalculatorPanel.createPanel().

synchronized void jscicalc.CalculatorPanel.paintComponent ( java.awt.Graphics graphics )

Paint the component: sets the colour for the background.

Parameters:

graphics

Needed for all paintComponent methods

References jscicalc.CalculatorPanel.colour.

void jscicalc.CalculatorPanel.setUp ( ) [private]

Creates a key map for the CalculatorApplet, puts in nonstandard buttons, asks the subclass method to set the standard buttons, and arranges all buttons in a SpringLayout.

References jscicalc.CalculatorPanel.applet, jscicalc.CalculatorPanel.buttons(), jscicalc.HEX, jscicalc.CalculatorPanel.keyMap(), jscicalc.CalculatorPanel.layout, jscicalc.CalculatorPanel.layoutSprings(), jscicalc.NONE, jscicalc.CalculatorPanel.sbt, jscicalc.CalculatorPanel.setButtons(), jscicalc.SHIFT, jscicalc.SHIFT_HEX, jscicalc.SHIFT_STAT, and jscicalc.STAT.

Referenced by jscicalc.CalculatorPanel.run().

abstract void jscicalc.CalculatorPanel.setButtons ( ) [protected, pure virtual]

Subclasses implement this so that they can define all the standard buttons like Numeral, Add, etc.

Nonstandard buttons (ModeButton, ShiftButton, ...) are handles separately by setUp().

Implemented in jscicalc.HexPanel, jscicalc.PlainPanel, jscicalc.ShiftHexPanel, jscicalc.ShiftPanel, jscicalc.ShiftStatPanel, and jscicalc.StatPanel.

Referenced by jscicalc.CalculatorPanel.setUp().

synchronized void jscicalc.CalculatorPanel.layoutSprings ( )

Long function that lays out buttons and DisplayPanel.

It uses a SpringLayout, which is very powerful but not well documented by Sun, to place the buttons exactly where I want them while allowing the whole calculator to be rescaled as required.

Referenced by jscicalc.CalculatorPanel.setUp().

synchronized void jscicalc.CalculatorPanel.setDisplayPanel ( )

References jscicalc.CalculatorPanel.applet, jscicalc.CalculatorPanel.displayHeightSpring, jscicalc.CalculatorApplet.displayPanel, jscicalc.CalculatorPanel.displayWidthSpring, jscicalc.CalculatorPanel.layout, jscicalc.CalculatorPanel.xBorderSpring, and jscicalc.CalculatorPanel.yBorderSpring.

Referenced by jscicalc.CalculatorApplet.setCalculatorPanel().

synchronized java.util.Vector<CalculatorButton> jscicalc.CalculatorPanel.buttons ( )

CalculatorApplet might need this.

Returns:: The list of buttons on this panel

Referenced by jscicalc.CalculatorPanel.createKeyMap(), jscicalc.CalculatorPanel.layoutSprings(), jscicalc.ShiftStatPanel.setButtons(), jscicalc.ShiftPanel.setButtons(), jscicalc.ShiftHexPanel.setButtons(), jscicalc.PlainPanel.setButtons(), jscicalc.HexPanel.setButtons(), and jscicalc.CalculatorPanel.setUp().

synchronized java.util.HashMap<Character,CalculatorButton> jscicalc.CalculatorPanel.keyMap ( )

CalculatorApplet uses this to handle keyboard shortcuts.

It needs to know the char associated with each button so that it can find the button and fire CalculatorButton.actionPerformed() as required.

Returns:: a map from characters to buttons

Referenced by jscicalc.CalculatorPanel.createKeyMap(), and jscicalc.CalculatorPanel.setUp().

void jscicalc.CalculatorPanel.createKeyMap ( ) [protected]

The method that creates the keyMap.

It has a debug feature that tells you if you’ve used any character twice. This is useful for detecting subtle problems.

References jscicalc.CalculatorPanel.buttons(), and jscicalc.CalculatorPanel.keyMap().

Referenced by jscicalc.ShiftPanel.setButtons(), jscicalc.ShiftHexPanel.setButtons(), jscicalc.PlainPanel.setButtons(), and jscicalc.HexPanel.setButtons().

Base jscicalc.CalculatorPanel.base ( )

I can’t rememeber why we have this.

Returns:: the base, which ought just to be the CalculatorApplet value.

Referenced by jscicalc.HexPanel.HexPanel(), and jscicalc.ShiftHexPanel.ShiftHexPanel().

void jscicalc.CalculatorPanel.base ( Base base )

I can’t rememeber why we have this.

Sets tha Base.

Parameters:

base

the base, which ought just to be the CalculatorApplet value.

Member Data Documentation

Base jscicalc.CalculatorPanel.base [private]

A Base.

I don’t know if we use this.

java.awt.Color jscicalc.CalculatorPanel.colour [protected]

Background colour.

Referenced by jscicalc.CalculatorPanel.CalculatorPanel(), jscicalc.CalculatorPanel.createPanel(), jscicalc.HexPanel.HexPanel(), jscicalc.CalculatorPanel.paintComponent(), jscicalc.PlainPanel.PlainPanel(), jscicalc.ShiftHexPanel.ShiftHexPanel(), jscicalc.ShiftPanel.ShiftPanel(), jscicalc.ShiftStatPanel.ShiftStatPanel(), and jscicalc.StatPanel.StatPanel().

javax.swing.Spring jscicalc.CalculatorPanel.xBorderSpring [private]

A Spring.

Probably doesn’t need to be a class member.

Referenced by jscicalc.CalculatorPanel.layoutSprings(), and jscicalc.CalculatorPanel.setDisplayPanel().

javax.swing.Spring jscicalc.CalculatorPanel.yBorderSpring [private]

A Spring.

Probably doesn’t need to be a class member.

Referenced by jscicalc.CalculatorPanel.layoutSprings(), and jscicalc.CalculatorPanel.setDisplayPanel().

javax.swing.Spring jscicalc.CalculatorPanel.strutX [private]

A Spring.

Probably doesn’t need to be a class member.

Referenced by jscicalc.CalculatorPanel.layoutSprings().

javax.swing.Spring jscicalc.CalculatorPanel.strutY [private]

A Spring.

Probably doesn’t need to be a class member.

Referenced by jscicalc.CalculatorPanel.layoutSprings().

javax.swing.Spring jscicalc.CalculatorPanel.minX [private]

A Spring.

Probably doesn’t need to be a class member.

Referenced by jscicalc.CalculatorPanel.layoutSprings().

javax.swing.Spring jscicalc.CalculatorPanel.minY [private]

A Spring.

Probably doesn’t need to be a class member.

Referenced by jscicalc.CalculatorPanel.layoutSprings().

javax.swing.Spring jscicalc.CalculatorPanel.buttonWidthSpring [private]

A Spring.

Probably doesn’t need to be a class member.

Referenced by jscicalc.CalculatorPanel.layoutSprings().

javax.swing.Spring jscicalc.CalculatorPanel.narrowButtonWidthSpring [private]

A Spring.

Probably doesn’t need to be a class member.

Referenced by jscicalc.CalculatorPanel.layoutSprings().

javax.swing.Spring jscicalc.CalculatorPanel.thinButtonWidthSpring [private]

A Spring.

Probably doesn’t need to be a class member.

Referenced by jscicalc.CalculatorPanel.layoutSprings().

javax.swing.Spring jscicalc.CalculatorPanel.buttonHeightSpring [private]

A Spring.

Probably doesn’t need to be a class member.

Referenced by jscicalc.CalculatorPanel.layoutSprings().

javax.swing.Spring jscicalc.CalculatorPanel.shortButtonHeightSpring [private]

A Spring.

Probably doesn’t need to be a class member.

Referenced by jscicalc.CalculatorPanel.layoutSprings().

javax.swing.Spring jscicalc.CalculatorPanel.shortButtonWidthSpring [private]

A Spring.

Probably doesn’t need to be a class member.

Referenced by jscicalc.CalculatorPanel.layoutSprings().

javax.swing.Spring jscicalc.CalculatorPanel.displayWidthSpring [private]

A Spring.

Probably doesn’t need to be a class member.

Referenced by jscicalc.CalculatorPanel.layoutSprings(), and jscicalc.CalculatorPanel.setDisplayPanel().

javax.swing.Spring jscicalc.CalculatorPanel.displayHeightSpring [private]

A Spring.

Probably doesn’t need to be a class member.

Referenced by jscicalc.CalculatorPanel.layoutSprings(), and jscicalc.CalculatorPanel.setDisplayPanel().

final CalculatorApplet jscicalc.CalculatorPanel.applet [protected]

We need to know the CalculatorApplet so we can assign it to buttons as we add them.

Referenced by jscicalc.CalculatorPanel.layoutSprings(), jscicalc.CalculatorPanel.setDisplayPanel(), and jscicalc.CalculatorPanel.setUp().

final SpecialButtonType jscicalc.CalculatorPanel.sbt [protected]

used to identify panels, which are accessed through a CalculatorPanel pointer.

Referenced by jscicalc.CalculatorPanel.setUp().

javax.swing.SpringLayout jscicalc.CalculatorPanel.layout [protected]

The Layout.

Probably doesn’t need to be a class member.

Referenced by jscicalc.CalculatorPanel.layoutSprings(), jscicalc.CalculatorPanel.setDisplayPanel(), and jscicalc.CalculatorPanel.setUp().

java.util.Vector<CalculatorButton> jscicalc.CalculatorPanel.buttons [protected]

The list of buttons.

Referenced by jscicalc.CalculatorApplet.keyPressed(), and jscicalc.CalculatorApplet.keyTyped().

java.util.HashMap<Character,CalculatorButton> jscicalc.CalculatorPanel.keyMap [protected]

A map used by CalculatorApplet to fire Action events to buttons based on keyboard presses.

See also:: keyMap()

Referenced by jscicalc.CalculatorApplet.keyTyped().

The documentation for this class was generated from the following file:

CalculatorPanel.java


Public Member Functions
synchronized void	run ()
	Required to implement Runnable interface.
synchronized void	paintComponent (java.awt.Graphics graphics)
	Paint the component: sets the colour for the background.
synchronized void	layoutSprings ()
	Long function that lays out buttons and DisplayPanel.
synchronized void	setDisplayPanel ()
synchronized java.util.Vector < CalculatorButton >	buttons ()
	CalculatorApplet might need this.
synchronized java.util.HashMap < Character, CalculatorButton >	keyMap ()
	CalculatorApplet uses this to handle keyboard shortcuts.
Base	base ()
	I can’t rememeber why we have this.
void	base (Base base)
	I can’t rememeber why we have this.
Static Public Member Functions
static CalculatorPanel	createPanel (CalculatorApplet applet, SpecialButtonType sbt, java.awt.Color colour)
	We use this rather than a constructor to create a CalculatorPanel because in practice we always want a subclass.
Protected Member Functions
	CalculatorPanel (CalculatorApplet applet, SpecialButtonType sbt, java.awt.Color colour)
	Constructor is protected so that this class never actually gets instantiated.
abstract void	setButtons ()
	Subclasses implement this so that they can define all the standard buttons like Numeral, Add, etc.
void	createKeyMap ()
	The method that creates the keyMap.
Protected Attributes
java.awt.Color	colour
	Background colour.
final CalculatorApplet	applet
	We need to know the CalculatorApplet so we can assign it to buttons as we add them.
final SpecialButtonType	sbt
	used to identify panels, which are accessed through a CalculatorPanel pointer.
javax.swing.SpringLayout	layout
	The Layout.
java.util.Vector < CalculatorButton >	buttons
	The list of buttons.
java.util.HashMap< Character, CalculatorButton >	keyMap
	A map used by CalculatorApplet to fire Action events to buttons based on keyboard presses.
Private Member Functions
void	setUp ()
	Creates a key map for the CalculatorApplet, puts in nonstandard buttons, asks the subclass method to set the standard buttons, and arranges all buttons in a SpringLayout.
Private Attributes
Base	base
	A Base.
javax.swing.Spring	xBorderSpring
	A Spring.
javax.swing.Spring	yBorderSpring
	A Spring.
javax.swing.Spring	strutX
	A Spring.
javax.swing.Spring	strutY
	A Spring.
javax.swing.Spring	minX
	A Spring.
javax.swing.Spring	minY
	A Spring.
javax.swing.Spring	buttonWidthSpring
	A Spring.
javax.swing.Spring	narrowButtonWidthSpring
	A Spring.
javax.swing.Spring	thinButtonWidthSpring
	A Spring.
javax.swing.Spring	buttonHeightSpring
	A Spring.
javax.swing.Spring	shortButtonHeightSpring
	A Spring.
javax.swing.Spring	shortButtonWidthSpring
	A Spring.
javax.swing.Spring	displayWidthSpring
	A Spring.
javax.swing.Spring	displayHeightSpring
	A Spring.