The previously advertized big upgrade is complete, so this page has been modified to reflect the results of the upgrade process. All of the Mathlets applets have been written in Java2 and compiled using the Java2 SDK v1.4.2 on Linux, as available directly from Sun Microsystems, along with (in some cases) JavaCC v3.2, available now through Sun's Developer Connection.

The edu.jsu.leathrum.mathlets.shared package contains the following classes (listed here in alphabetical order):

• AButtonSet implements FieldHandler, ActionListener -- abstract class, provides "name=value" label and two RepeatingButton's ("+" and "-"), subclass must implement button actions
• interface ActionWrapper requires method doThis() -- general way of storing a parameterless method
• AGraphPanel -- abstract class, panel which includes an AGraphCanvas and buttons linked to the graph manipulation methods in AGraphCanvas, subclass must initialize (calling method initpanel()) with instantiated subclass of AGraphCanvas
  inner classes:
  • AGraphCanvas -- abstract class, this is the basic graphing canvas, includes methods for graph manipulations such as zooming and mouse tracking, subclass must implement abstract drawFigure() method to do the actual drawing, may also override buildFigure() and drawFirst() methods
  • CoordsConverter -- converts between graphing coordinates and pixel drawing coordinates
  • WindowPanel -- panel for pop-up window for graph axis bounds settings using several DoubleInputSet's and buttons
• AGraphPanel3d -- abstract class, 3-D version of AGraphPanel, fewer buttons since no zooming or mouse tracking available
  inner classes:
  • AGraphCanvas3d -- abstract class, the basic 3-D graphing canvas, the 3-D version of AGraphCanvas, more sophisticated axis and coordinate transformations, but zooming and mouse tracking methods not available
  • CoordsConverter3d -- 3-D version of CoordsConverter, includes 3-D to 2-D projection code
  • WindowPanel -- 3-D version of WindowPanel, more axis bounds to set
  • ViewPanel -- panel for pop-up window for view angle and graph grid settings using several DoubleInputSet's and buttons
  • ViewPtPanel -- panel for pop-up window for view point settings using several DoubleInputSet's and buttons, point translated to angles for ViewPanel3d
• AGraphPanel3dFacets extends AGraphPanel3d -- abstract class, with inner class AGraphCanvas3dFacets extending AGraphCanvas3d, includes code to implement faceted surface representation of 3-D graphs
  inner classes:
  • Facets -- dynamic array of DoubleTriad's, represents one "facet", painted as opaque polygon, includes drawing code using CoordsConverter3d for projection
  • GraphModelFacets -- dynamic array of Facet's (entire surface), also includes sorting code for implementing front-back "hiding" of surface
• AGraphPanel3dWires extends AGraphCanvas3d-- abstract class, with inner class AGraphCanvas3dWires extending AGraphCanvas3d, includes code to implement wireframe representation of 3-D graphs
  inner classes
  • Path -- dynamic array of DoubleTriad's, represents one "wire", painted as sequence of line segments, includes drawing code using CoordsConverter3d for projection
  • GraphModelWires -- dynamic array of Path's (entire wireframe)
• AMathlet extends JApplet -- the main class that all applets in the Mathlets set extend, implements handling of return-key events in input fields, major button events, JavaScript interface, HTML parameters
  abstract methods:
  • localinit() for applet-specific initialization, including setting label contents based on Locale data
  • draw() for applet-specific graphing procedures
  other important methods:
  • localclear() empty by default, can be overridden with applet-specific procedures for clearing applet fields and graphs)
  • setHandler() registers a FieldHandler with an associated parameter name, for JavaScript interface and HTML parameter handling
  • registerInputSet() registers an InputSet with a local KeyHandlerSequence
  • registerGraphButton() registers a button with a local ButtonList, associates a call to the draw() method with the button
  • registerClearButton() registers a button with a local ButtonList, associates a call to the private clear() method with the button, calls setToDefault() on all fields registered with setHandler(), then calls localclear() and draw()
  • getNumberFormat() returns DecimalFormat associated with the Locale
  • getProperty() gets data from properties files based on Locale
• AParserInputSet extends InputSet -- abstract class, interprets text in input field as expression for Parser, includes code for evaluating stack returned by Parser, subclass must implement setVars() and getVar() methods to establish how to handle variables
• ASimpleGraphCanvas -- abstract class, simplified graphing canvas without all of the manipulation methods, subclass must implement drawFigure() method for actual figure to be drawn
• ButtonList, inner class Listener implements ActionListener -- method registerButton(AbstractButton, ActionWrapper) associates button with action, so that clicking the button causes a call to the ActionWrapper's doThis() method
• DblButtonSet extends AButtonSet -- button set designed for handling double values
• DoubleInputSet extends InputSet -- input set designed for handling double values
• DoubleTriad -- simple data type with three double's
• interface FieldHandler requires methods setDefault() setToDefault() setField() getField() -- this is the interface by which InputSet's are enabled to handle the JavaScript interface (see InputSet for typical basic implementation, AMathlet for the actual methods of the JavaScript interface)
• FixedWidthLabel extends MLabel, implements label with fixed width, to make layout easier with dynamic labels
• FormattedFixedWidthLabel extends FormattedLabel, implements formatted label with fixed width, to make layout easier with dynamic labels
• FormattedLabel extends MLabel-- extends MLabel, implements simple character formatting, including subscripts, superscripts, and half-width spaces, also includes code for some Unicode character substitutions (Greek letters, a few math symbols), makes heavy use of Java2 HTML capabilities
• InputSet implements KeyHandler, FieldHandler -- basic input set (label plus text input field), options include checkbox, color labels, additional label after field
• IntButtonSet extends AButtonSet -- button set for handling integer values
• IntInputSet extends InputSet -- input set designed for handling integer values
• interface KeyHandler requires methods isKey() doKeyAction() addKeyListener() requestFocus() -- interface by which return-key events select within a sequence of InputSet's (see KeyHandlerSequence and InputSet for typical uses), typically on a key event the event is checked to see if isKey() returns true, and if so, the doKeyAction() event is called (other required methods analogous to JComponent versions)
• KeyHandlerSequence inner class Listener implements KeyListener -- method registerKeyHandler(KeyHandler, ActionWrapper) associates an action with a KeyHandler's specially-handled key event, similar to how a ButtonList associates an action with a button (method registerKeyHandler(KeyHandler) associates a NullAction with the key), then moves input focus to the next KeyHandler in the sequence
• MLabel extends JLabel -- utility extension of JLabel to implement some methods simplifying changes of font size and style, and to make some of the JLabel painting commands accessible to subclasses
• NullAction implements ActionWrapper -- the doThis() method does nothing
• Parser and other classes derived from JavaCC file Parser.jj -- implement the expression parser, input is string, output is stack representation of parsed string
• RepeatingButton extends JButton, captures the button's click event, repeats it as long as the button is being held down (using a Swing Timer)

• Parabolas (ASimpleGraphCanvas, DblButtonSet; implicitly includes AButtonSet, RepeatingButton, extensions of MLabel)
• Tangent Lines (AGraphPanel and its inner classes, AParserInputSet, DoubleInputSet; implicitly includes Parser and related classes, InputSet, extensions of MLabel)
• 3-D Graphing (AGraphPanel3dFacets and its inner classes, AParserInputSet; implicitly includes AGraphPanel3d and its inner classes, Parser and related classes, DoubleInputSet, InputSet, extensions of MLabel, DoubleTriad) -- see also wireframe form, using AGraphPanel3dWires
• Basic Animation: Limits incorporates a basic animated sequence. None of the other applets use such a sequence, so this code is not shared. This applet does use AParserInputSet and DoubleInputSet.
• I'm pretty proud of my Derivative Calculator applet, so I decided to include the code from it here as well. It uses its own parser (also written in JavaCC), which returns a parse tree rather than a stack representation of the expression. To implement and construct the tree, the applet uses a basic node class and a specialized utility tree building class (which uses a stack to keep track of newly added children). The TParserInputSet class, which extends the shared InputSet class, contains most of the heavy code, including the actual derivative algorithm (in the "derivator()" method) and an unparsing algorithm (translating from parse tree back to string, in the "evaluateTree()" method). The MenuGroup class (an inner class of the main applet class) is my first use of a pop-up menu, in this case to select a variable for partial derivatives.
• For development purposes, I use a short general-purpose "wrapper" application which loads an applet and displays it as a separate window within the full application. The application includes code which allows HTML parameters to be specified on the command line.