Class EmissionApplet

java.lang.Object
  |
  +--java.awt.Component
        |
        +--java.awt.Container
              |
              +--java.awt.Panel
                    |
                    +--java.applet.Applet
                          |
                          +--BaseApplet
                                |
                                +--BaseApplet2
                                      |
                                      +--EmissionApplet

Direct Known Subclasses:

FeedbackApplet

public class EmissionApplet

extends BaseApplet2

implements java.lang.Runnable

Displays an animated diagram to illustrate absorption, emission (spontaneous and stimulated) and pumping.

See Also:

Serialized Form

Inner Class Summary

class	EmissionApplet.Electron Models an electron
class	EmissionApplet.Photon Models a photon

Inner classes inherited from class BaseApplet2

BaseApplet2.FixedButton, BaseApplet2.FixedCheckbox, BaseApplet2.GraphClickListener

Inner classes inherited from class BaseApplet

BaseApplet.MozillaWorkaround, BaseApplet.ResizeListener

Inner classes inherited from class java.awt.Component

java.awt.Component.AWTTreeLock

Field Summary

protected double	absorb Probability that a passing photon will be absorbed by a particular electron
protected java.awt.TextField	absorbField
protected java.awt.Button	destroy
protected boolean	destroyPhotons Indicates that on the next logic cycle, all photons should be culled
protected double	dt The rate of advancement of simulation time
protected EmissionApplet.Electron[]	electrons An array of all the electrons in the simulation
protected double	electronSpeed The ratio of electron speed to photon speed
protected double	emit Probability that a passing photon will trigger an emission from a particular electron
protected java.awt.TextField	emitField
protected java.awt.Button	exciteAll
protected int	excitedY The y coordinate at which excited electrons should be drawn
protected java.awt.Button	exciteNone
protected double	hGap The width (in simulation units) of the spacing between electrons
protected int	hMargin
protected java.awt.TextField	inversionField
protected java.awt.Button	invert
protected double	margin Proportion of the simulation reserved at the top and bottom for electrons.
protected int	normalY The y coordinate at which non-excited electrons should be drawn
protected java.util.Vector	photons A list of all the photons in the simulation
protected double	pump Average proportion of non-excited electrons which will be pumped to the upper energy level in the time it takes for a photon to pass through the simulation.
protected java.awt.TextField	pumpField
protected double	simH The width (in simulation units) of the simulation
protected double	simW The width (in simulation units) of the simulation
protected int[]	sinTable Cache of sine values
protected double	spont Average proportion of excited electrons which will spontaneously emit a photon in the time it takes for a photon to pass through the simulation.
protected java.awt.TextField	spontField
protected java.lang.Thread	thr The thread used to perform the work of the simulation
protected int	vMargin
protected int	waveDispLen

Fields inherited from class BaseApplet2

boxes, buttons, enablePrompt, fields, focus, panel, statusLabel, useSwing, V_MARGIN

Fields inherited from class BaseApplet

buffer, GRAPH_MARGIN, refresh, resizeListener, safetyLimit, useBuffer

Fields inherited from class java.applet.Applet

serialVersionUID, stub

Fields inherited from class java.awt.Panel

base, nameCounter, serialVersionUID

Fields inherited from class java.awt.Container

component, containerListener, containerSerializedDataVersion, dispatcher, layoutMgr, maxSize, ncomponents, serialVersionUID

Fields inherited from class java.awt.Component

actionListenerK, adjustmentListenerK, appContext, assert, background, BOTTOM_ALIGNMENT, CENTER_ALIGNMENT, changeSupport, componentListener, componentListenerK, componentOrientation, componentSerializedDataVersion, containerListenerK, cursor, dropTarget, enabled, eventMask, focusListener, focusListenerK, font, foreground, hasFocus, height, incRate, inputMethodListener, inputMethodListenerK, isInc, isPacked, itemListenerK, keyListener, keyListenerK, LEFT_ALIGNMENT, locale, LOCK, minSize, mouseListener, mouseListenerK, mouseMotionListener, mouseMotionListenerK, name, nameExplicitlySet, newEventsOnly, ownedWindowK, parent, peer, peerFont, popups, prefSize, RIGHT_ALIGNMENT, serialVersionUID, textListenerK, TOP_ALIGNMENT, valid, visible, width, windowListenerK, x, y

Constructor Summary

EmissionApplet()

Method Summary

void	actionPerformed(java.awt.event.ActionEvent ae) Subclasses should at least provide an empty implementation of this method.
protected void	addFields() Adds the text fields to the GUI
void	buildSineTable(int len, int amp) Creates a table of sine values (for painting the photons as waves).
double	calcInversion() Measures the population inversion (the proportion of electrons at the upper energy level.
void	createElectrons() Part of initialisation; creates a row of electrons, with spacing determined by hGap.
protected int	cullPhotons() Removes from the list any photons which have left the simulation.
void	destroyPhotons() Causes all photons in the simulation to be destroyed
void	doPaint(java.awt.Graphics g) Called by forcePaint() to actually perform the painting.
protected EmissionApplet.Electron	findElectron(double left, double right) Finds the first electron within a specified interval.
void	init() Performs extra initialisation, including adding a panel to the bottom of the applet.
void	invert() Applys the selected inversion to the electrons.
void	killAnim() Requests that the currently running simulation should stop at the next opportunity.
protected void	paintElectrons(java.awt.Graphics g, double xscl, double yscl) Paints all the electrons in the simulation.
protected void	paintPhotons(java.awt.Graphics g, double xscl, double yscl) Paints all the photons in the simulation.
protected void	paintWave(java.awt.Graphics g, int x, int y, int amp, double wavelength, int phase) Paints a sine wave to represent a photon.
void	run() Performs the work of the simulation: an update/repaint loop.
void	setAllExcited(boolean b) Sets all the electrons to either the upper or lower energy level.
int	sin(int x) Looks up the sin value to use for a particular x.
void	spawnPhoton() Creates a new photon at the "start" end of the simulation, with random vertical position (of no real consequence), and random phase.
void	start() Applets should use this method to perform any final initialisation necessary to "activate" the applet
void	startAnim() Requests that the simulation be started.
void	stop() When this method is called, the applet should cease any user interaction.
void	updateElectrons(double dt) Calls the update() method of every electron, thus advancing them through the specified time interval.
void	updateInput() Reads in (and validates) input from the text fields.
void	updatePhotons(double dt) Calls the update() method of every photon, thus advancing them through the specified time interval.

Methods inherited from class BaseApplet2

add, add, addButton, addCheckbox, addField, addField, addField, addListeners, focusGained, focusLost, getDouble, getGraphHeight, getInt, lockControls, makeButton, makePanel, paintDashedLineH, paintDashedLineV, register, removeListeners, setComponentsEnabled, setLayout, setPromptEnabled, textValueChanged, toString, unlockControls

Methods inherited from class BaseApplet

changeFont, forcePaint, getAppletInfo, getParameterInfo, itemStateChanged, paint, refresh, update

Methods inherited from class java.applet.Applet

destroy, getAppletContext, getAudioClip, getAudioClip, getCodeBase, getDocumentBase, getImage, getImage, getLocale, getParameter, isActive, newAudioClip, play, play, resize, resize, setStub, showStatus

Methods inherited from class java.awt.Panel

, addNotify, constructComponentName

Methods inherited from class java.awt.Container

add, add, add, add, addContainerListener, addImpl, applyOrientation, countComponents, deliverEvent, dispatchEventImpl, dispatchEventToSelf, doLayout, eventEnabled, findComponentAt, findComponentAt, getAlignmentX, getAlignmentY, getComponent, getComponentAt, getComponentAt, getComponentCount, getComponents_NoClientCode, getComponents, getCursorTarget, getInsets, getLayout, getMaximumSize, getMinimumSize, getMouseEventTarget, getPreferredSize, getWindow, initIDs, insets, invalidate, invalidateTree, isAncestorOf, layout, lightweightPrint, list, list, locate, minimumSize, nextFocus, paintComponents, paramString, postProcessKeyEvent, postsOldMouseEvents, preferredSize, preProcessKeyEvent, print, printComponents, printOneComponent, processContainerEvent, processEvent, proxyEnableEvents, proxyRequestFocus, readObject, remove, remove, removeAll, removeContainerListener, removeNotify, setCursor, setFocusOwner, setFont, transferFocus, updateCursor, validate, validateTree, writeObject

Methods inherited from class java.awt.Component

action, add, addComponentListener, addFocusListener, addInputMethodListener, addKeyListener, addMouseListener, addMouseMotionListener, addPropertyChangeListener, addPropertyChangeListener, areInputMethodsEnabled, bounds, checkImage, checkImage, coalesceEvents, contains, contains, createImage, createImage, disable, disableEvents, dispatchEvent, enable, enable, enableEvents, enableInputMethods, firePropertyChange, getBackground, getBounds, getBounds, getColorModel, getComponentOrientation, getCursor, getDropTarget, getFont_NoClientCode, getFont, getFontMetrics, getForeground, getGraphics, getHeight, getInputContext, getInputMethodRequests, getIntrinsicCursor, getLocation, getLocation, getLocationOnScreen, getName, getNativeContainer, getParent_NoClientCode, getParent, getPeer, getSize, getSize, getToolkit, getToolkitImpl, getTreeLock, getWidth, getWindowForObject, getX, getY, gotFocus, handleEvent, hasFocus, hide, imageUpdate, inside, isDisplayable, isDoubleBuffered, isEnabled, isEnabledImpl, isFocusTraversable, isLightweight, isOpaque, isShowing, isValid, isVisible, keyDown, keyUp, list, list, list, location, lostFocus, mouseDown, mouseDrag, mouseEnter, mouseExit, mouseMove, mouseUp, move, nextFocus, paintAll, postEvent, prepareImage, prepareImage, printAll, processComponentEvent, processFocusEvent, processInputMethodEvent, processKeyEvent, processMouseEvent, processMouseMotionEvent, remove, removeComponentListener, removeFocusListener, removeInputMethodListener, removeKeyListener, removeMouseListener, removeMouseMotionListener, removePropertyChangeListener, removePropertyChangeListener, repaint, repaint, repaint, repaint, requestFocus, reshape, setBackground, setBounds, setBounds, setComponentOrientation, setDropTarget, setEnabled, setForeground, setLocale, setLocation, setLocation, setName, setSize, setSize, setVisible, show, show, size, toString, transferFocus

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, registerNatives, wait, wait, wait

Field Detail

destroyPhotons

protected boolean destroyPhotons

Indicates that on the next logic cycle, all photons should be culled

absorb

protected double absorb

Probability that a passing photon will be absorbed by a particular electron

emit

protected double emit

Probability that a passing photon will trigger an emission from a particular electron

spont

protected double spont

Average proportion of excited electrons which will spontaneously emit a photon in the time it takes for a photon to pass through the simulation.

pump

protected double pump

Average proportion of non-excited electrons which will be pumped to the upper energy level in the time it takes for a photon to pass through the simulation.

thr

protected java.lang.Thread thr

The thread used to perform the work of the simulation

photons

protected java.util.Vector photons

A list of all the photons in the simulation

electrons

protected EmissionApplet.Electron[] electrons

An array of all the electrons in the simulation

simW

protected double simW

The width (in simulation units) of the simulation

simH

protected double simH

The width (in simulation units) of the simulation

hGap

protected double hGap

The width (in simulation units) of the spacing between electrons

dt

protected double dt

The rate of advancement of simulation time

electronSpeed

protected double electronSpeed

The ratio of electron speed to photon speed

margin

protected double margin

Proportion of the simulation reserved at the top and bottom for electrons. No photons will be created in those regions.

excitedY

protected int excitedY

The y coordinate at which excited electrons should be drawn

normalY

protected int normalY

The y coordinate at which non-excited electrons should be drawn

waveDispLen

protected int waveDispLen

hMargin

protected int hMargin

vMargin

protected int vMargin

sinTable

protected int[] sinTable

Cache of sine values

absorbField

protected java.awt.TextField absorbField

emitField

protected java.awt.TextField emitField

spontField

protected java.awt.TextField spontField

inversionField

protected java.awt.TextField inversionField

pumpField

protected java.awt.TextField pumpField

exciteAll

protected java.awt.Button exciteAll

exciteNone

protected java.awt.Button exciteNone

invert

protected java.awt.Button invert

destroy

protected java.awt.Button destroy

Constructor Detail

EmissionApplet

public EmissionApplet()

Method Detail

init

public void init()

Description copied from class: BaseApplet2

Performs extra initialisation, including adding a panel to the bottom of the applet.

Overrides:

init in class BaseApplet2

addFields

protected void addFields()

Adds the text fields to the GUI

start

public void start()

Description copied from class: BaseApplet

Applets should use this method to perform any final initialisation necessary to "activate" the applet

Overrides:

start in class BaseApplet2

stop

public void stop()

Description copied from class: BaseApplet

When this method is called, the applet should cease any user interaction. In particular, any threads explicitly started should be stopped, any external resources should be closed. This method should negate the action of start().

Overrides:

stop in class BaseApplet2

doPaint

public void doPaint(java.awt.Graphics g)

Description copied from class: BaseApplet

Called by forcePaint() to actually perform the painting. Subclasses should implement this method as if it were the standard paint() method; buffering will then take place transparently.

Overrides:

doPaint in class BaseApplet

Tags copied from class: BaseApplet

Parameters:

g - The Graphics object on which to paint

paintPhotons

protected void paintPhotons(java.awt.Graphics g,
                            double xscl,
                            double yscl)

Paints all the photons in the simulation.

Parameters:

g - The Graphics surface on which to paint

xscl - Multiplier to convert simulation x coordinates to screen coordinates

yscl - Multiplier to convert simulation y coordinates to screen coordinates

paintElectrons

protected void paintElectrons(java.awt.Graphics g,
                              double xscl,
                              double yscl)

Paints all the electrons in the simulation.

Parameters:

g - The Graphics surface on which to paint

xscl - Multiplier to convert simulation x coordinates to screen coordinates

yscl - Multiplier to convert simulation y coordinates to screen coordinates

updateInput

public void updateInput()

Reads in (and validates) input from the text fields.

Throws:

java.lang.IllegalArgumentException - if any input fields are invalid

actionPerformed

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

Description copied from class: BaseApplet

Subclasses should at least provide an empty implementation of this method.

Overrides:

actionPerformed in class BaseApplet

createElectrons

public void createElectrons()

Part of initialisation; creates a row of electrons, with spacing determined by hGap. Any prior existing electrons will be lost; all newly created electrons will be at the lower energy level.

updatePhotons

public void updatePhotons(double dt)

Calls the update() method of every photon, thus advancing them through the specified time interval. If there are currently no photons in the simulation, spawnPhoton() will be called to create one.

updateElectrons

public void updateElectrons(double dt)

Calls the update() method of every electron, thus advancing them through the specified time interval.

cullPhotons

protected int cullPhotons()

Removes from the list any photons which have left the simulation.

Returns:

The number of photons leaving

spawnPhoton

public void spawnPhoton()

Creates a new photon at the "start" end of the simulation, with random vertical position (of no real consequence), and random phase.

run

public void run()

Performs the work of the simulation: an update/repaint loop.

Specified by:

run in interface java.lang.Runnable

startAnim

public void startAnim()

Requests that the simulation be started. If a simulation is already in progress, this method will have no effect.

killAnim

public void killAnim()

Requests that the currently running simulation should stop at the next opportunity. If no simulation is running, this method will have no effect.

buildSineTable

public void buildSineTable(int len,
                           int amp)

Creates a table of sine values (for painting the photons as waves).

Parameters:

len - The wavelength, in pixels

amp - The amplitude, in pixels

sin

public int sin(int x)

Looks up the sin value to use for a particular x. Since this used the table built by buildSineTable(), it's much faster than Math.sin().

paintWave

protected void paintWave(java.awt.Graphics g,
                         int x,
                         int y,
                         int amp,
                         double wavelength,
                         int phase)

Paints a sine wave to represent a photon.

Parameters:

g - The Graphics surface on which to paint

x - The x coordinate of the leading end of the wave

y - The y coordinate of the leading end of the wave

amp - ignored; all waves now use the cached sine table

wavelength - used only to determine how much wave to draw.

phase - The phase shift for the wave

findElectron

protected EmissionApplet.Electron findElectron(double left,
                                               double right)

Finds the first electron within a specified interval. Used by photons to find an electron to interact with.

setAllExcited

public void setAllExcited(boolean b)

Sets all the electrons to either the upper or lower energy level.

Parameters:

b - true if all electrons should be excited, false if all electrins should be unexcited (bored?)

invert

public void invert()

Applys the selected inversion to the electrons. Electrons will be randomly distributed according to the inversion, with no regard to their previous energy level.

calcInversion

public double calcInversion()

Measures the population inversion (the proportion of electrons at the upper energy level.

destroyPhotons

public void destroyPhotons()

Causes all photons in the simulation to be destroyed