Class ConceptWebClient

java.lang.Object
  java.awt.Component
      java.awt.Container
          java.awt.Panel
              java.applet.Applet
                  ConceptWebClient

All Implemented Interfaces:

javax.accessibility.Accessible, java.awt.event.ActionListener, java.util.EventListener, java.awt.image.ImageObserver, java.awt.MenuContainer, java.awt.event.MouseListener, java.awt.event.MouseMotionListener, java.io.Serializable

public class ConceptWebClient

extends java.applet.Applet

implements java.awt.event.MouseListener, java.awt.event.MouseMotionListener, java.awt.event.ActionListener

The ConceptWebClient class is the main class for the web client. It presents a concept map drawing tool similar in functionality to Dia, Visio (tm) or other schematic tools. The feature set implemented by this class is not as exhaustive as standard schematic tools; rather, it is limited to those features necessary to draw a concept map generally involving ten words or less. This reduces the size of the applet so as to be realistic in terms of network bandwidth as well as simplifying users' ability to understand and work with the applet interface.

Technical Notes

• This code currently conforms to the API for java version 1.3.
• Browser compatibility has required that much of the interface be encoded with exact pixel sizes as opposed to a flexibly-sized layout strategy.
• Exact pixel sizes also help track mouse actions on the graphical palette given the weak browser java support for AWT objects and events.

Description of pixel-based, graphical layout:
          <----------- applet_width ----------->
       
       ^   ------------------------------------
       |  |    ^                        ^      |
       |  |    |         top_space      |      |
       a  |    V                        V      |
       p  |------------------------------------|
       p  |<->|<------- space_width ------>|<->|
       l  | l |      ^                     | r |
       e  | e |      |                     | g |
       t  | f | space_height               | h |
       _  | t |      |                     | t |
       h  | s |      |                     | s |
       e  | p |      |                     | p |
       i  | a |      |                     | a |
       g  | c |      |                     | c |
       h  | e |      V                     | e |
       t  |------------------------------------|
       |  |    ^                        ^      |
       |  |    |       bottom_space     |      |
       |  |    V                        V      |
       V   ------------------------------------

Since:

JDK 1.3.1

See Also:

Serialized Form

Nested Class Summary

Nested classes inherited from class java.applet.Applet

java.applet.Applet.AccessibleApplet

Nested classes inherited from class java.awt.Panel

java.awt.Panel.AccessibleAWTPanel

Nested classes inherited from class java.awt.Container

java.awt.Container.AccessibleAWTContainer

Nested classes inherited from class java.awt.Component

java.awt.Component.AccessibleAWTComponent, java.awt.Component.BltBufferStrategy, java.awt.Component.FlipBufferStrategy

Field Summary

Fields inherited from class java.awt.Component

BOTTOM_ALIGNMENT, CENTER_ALIGNMENT, LEFT_ALIGNMENT, RIGHT_ALIGNMENT, TOP_ALIGNMENT

Fields inherited from interface java.awt.image.ImageObserver

ABORT, ALLBITS, ERROR, FRAMEBITS, HEIGHT, PROPERTIES, SOMEBITS, WIDTH

Constructor Summary

ConceptWebClient()
Constructor.

Method Summary

void	actionPerformed(java.awt.event.ActionEvent event) Whenever an event occurs for an interface object.
void	destroy() Cleans up memory.
void	init() Run once at beginning of program.
boolean	is_disabled(int num) Is a given feature number disabled? In order to condense the feature list, I am indexing them as numbers.
void	mouseClicked(java.awt.event.MouseEvent e) Nothing happens.
void	mouseDragged(java.awt.event.MouseEvent e) What to do when mouse is in motion.
void	mouseEntered(java.awt.event.MouseEvent e) Nothing happens.
void	mouseExited(java.awt.event.MouseEvent e) Nothing happens.
void	mouseMoved(java.awt.event.MouseEvent e)
void	mousePressed(java.awt.event.MouseEvent e) What to do when mouse button is pressed.
void	mouseReleased(java.awt.event.MouseEvent e) What to do when mouse button is released.
void	paint(java.awt.Graphics g) Coordinates push_information_everywhere invocation.
void	push_information_everywhere(java.awt.Graphics g, java.awt.Rectangle clip) Pushes information.
static void	stringlist_shuffle(java.lang.String[] string_list) Take a list of strings and shuffle them.
java.lang.String	unescape(java.lang.String word) Unescape string.
void	update(java.awt.Graphics g) Whenever the applet needs to update.

Methods inherited from class java.applet.Applet

getAccessibleContext, getAppletContext, getAppletInfo, getAudioClip, getAudioClip, getCodeBase, getDocumentBase, getImage, getImage, getLocale, getParameter, getParameterInfo, isActive, newAudioClip, play, play, resize, resize, setStub, showStatus, start, stop

Methods inherited from class java.awt.Panel

addNotify

Methods inherited from class java.awt.Container

add, add, add, add, add, addContainerListener, addImpl, addPropertyChangeListener, addPropertyChangeListener, applyComponentOrientation, areFocusTraversalKeysSet, countComponents, deliverEvent, doLayout, findComponentAt, findComponentAt, getAlignmentX, getAlignmentY, getComponent, getComponentAt, getComponentAt, getComponentCount, getComponents, getContainerListeners, getFocusTraversalKeys, getFocusTraversalPolicy, getInsets, getLayout, getListeners, getMaximumSize, getMinimumSize, getPreferredSize, insets, invalidate, isAncestorOf, isFocusCycleRoot, isFocusCycleRoot, isFocusTraversalPolicySet, layout, list, list, locate, minimumSize, paintComponents, paramString, preferredSize, print, printComponents, processContainerEvent, processEvent, remove, remove, removeAll, removeContainerListener, removeNotify, setFocusCycleRoot, setFocusTraversalKeys, setFocusTraversalPolicy, setFont, setLayout, transferFocusBackward, transferFocusDownCycle, validate, validateTree

Methods inherited from class java.awt.Component

action, add, addComponentListener, addFocusListener, addHierarchyBoundsListener, addHierarchyListener, addInputMethodListener, addKeyListener, addMouseListener, addMouseMotionListener, addMouseWheelListener, bounds, checkImage, checkImage, coalesceEvents, contains, contains, createImage, createImage, createVolatileImage, createVolatileImage, disable, disableEvents, dispatchEvent, enable, enable, enableEvents, enableInputMethods, firePropertyChange, firePropertyChange, firePropertyChange, getBackground, getBounds, getBounds, getColorModel, getComponentListeners, getComponentOrientation, getCursor, getDropTarget, getFocusCycleRootAncestor, getFocusListeners, getFocusTraversalKeysEnabled, getFont, getFontMetrics, getForeground, getGraphics, getGraphicsConfiguration, getHeight, getHierarchyBoundsListeners, getHierarchyListeners, getIgnoreRepaint, getInputContext, getInputMethodListeners, getInputMethodRequests, getKeyListeners, getLocation, getLocation, getLocationOnScreen, getMouseListeners, getMouseMotionListeners, getMouseWheelListeners, getName, getParent, getPeer, getPropertyChangeListeners, getPropertyChangeListeners, getSize, getSize, getToolkit, getTreeLock, getWidth, getX, getY, gotFocus, handleEvent, hasFocus, hide, imageUpdate, inside, isBackgroundSet, isCursorSet, isDisplayable, isDoubleBuffered, isEnabled, isFocusable, isFocusOwner, isFocusTraversable, isFontSet, isForegroundSet, 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, processHierarchyBoundsEvent, processHierarchyEvent, processInputMethodEvent, processKeyEvent, processMouseEvent, processMouseMotionEvent, processMouseWheelEvent, remove, removeComponentListener, removeFocusListener, removeHierarchyBoundsListener, removeHierarchyListener, removeInputMethodListener, removeKeyListener, removeMouseListener, removeMouseMotionListener, removeMouseWheelListener, removePropertyChangeListener, removePropertyChangeListener, repaint, repaint, repaint, repaint, requestFocus, requestFocus, requestFocusInWindow, requestFocusInWindow, reshape, setBackground, setBounds, setBounds, setComponentOrientation, setCursor, setDropTarget, setEnabled, setFocusable, setFocusTraversalKeysEnabled, setForeground, setIgnoreRepaint, setLocale, setLocation, setLocation, setName, setSize, setSize, setVisible, show, show, size, toString, transferFocus, transferFocusUpCycle

Methods inherited from class java.lang.Object

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

Constructor Detail

ConceptWebClient

public ConceptWebClient()

Constructor. Things to do before launching applet in runtime environment.

Method Detail

unescape

public java.lang.String unescape(java.lang.String word)

Unescape string. A '@' ("at" sign) + ';' ("semicolon" sign) combination is used since java's getParameter method can pre-empt processing of ampersand-semicolon escaping.

Parameters:

word - The word to substitute escaped values with "real" values.

stringlist_shuffle

public static void stringlist_shuffle(java.lang.String[] string_list)

Take a list of strings and shuffle them.

Parameters:

string_list - The list to shuffle.

init

public void init()

Run once at beginning of program. Initializes values with various predefined constants. (Note that this is a very lengthy method.)

push_information_everywhere

public void push_information_everywhere(java.awt.Graphics g,
                                        java.awt.Rectangle clip)

Pushes information.

Currently a lot of logic occurs inside here. This function brings together the pushing of information onto the:

• client screen (web browser)
• network (URL or URI requests)
• internal interface state changes (as painting the menu is accomplished, interface state data is immediately recorded)

Other interface state changes also occur here such as drawing in color mode versus gray mode. The strategic idea regarding this function was inspired by the fact that different java virtual machines invoke the the paint and update methods at irreconcilably different times. Thus, the goal is to synchronize the pushing of information in one function as opposed to relying on paint, update, or repaint to do everything consistently.

In some respects, an additional advantage to this strategy is that it makes the code organization less diffuse and, for the programmer, helps process all information that needs to be passed to the user in a concerted manner.

paint

public void paint(java.awt.Graphics g)

Coordinates push_information_everywhere invocation. Standard applet method. Should try and use screen buffer if available. This method invokes the push_information_everywhere method. (push_information_everywhere combines painting with a number of other network and internal state transactions).

destroy

public void destroy()

Cleans up memory. Standard applet method. Dispose of buffered screen memory if it exists.

update

public void update(java.awt.Graphics g)

Whenever the applet needs to update. Standard applet method. Simply call the paint method.

actionPerformed

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

Whenever an event occurs for an interface object. ActionListener method. Currently, no events for any objects are handled, since there are a few browser compatibility issues with AWT object events.

Specified by:

actionPerformed in interface java.awt.event.ActionListener

mouseMoved

public void mouseMoved(java.awt.event.MouseEvent e)

Specified by:

mouseMoved in interface java.awt.event.MouseMotionListener

mouseDragged

public void mouseDragged(java.awt.event.MouseEvent e)

What to do when mouse is in motion. Note: selected areas of the applet are redrawn only when the interface is in "MOVE" mode.

Specified by:

mouseDragged in interface java.awt.event.MouseMotionListener

mouseClicked

public void mouseClicked(java.awt.event.MouseEvent e)

Nothing happens.

Specified by:

mouseClicked in interface java.awt.event.MouseListener

mouseEntered

public void mouseEntered(java.awt.event.MouseEvent e)

Nothing happens.

Specified by:

mouseEntered in interface java.awt.event.MouseListener

mouseExited

public void mouseExited(java.awt.event.MouseEvent e)

Nothing happens.

Specified by:

mouseExited in interface java.awt.event.MouseListener

mouseReleased

public void mouseReleased(java.awt.event.MouseEvent e)

What to do when mouse button is released. Note: redraw the entire applet. Also, record that no word is selected.

Specified by:

mouseReleased in interface java.awt.event.MouseListener

mousePressed

public void mousePressed(java.awt.event.MouseEvent e)

What to do when mouse button is pressed. Note: determine the object that was hit based upon the mouse pointer coordinates. Based on the number of possibilities, this is a lengthy method.

Specified by:

mousePressed in interface java.awt.event.MouseListener

is_disabled

public boolean is_disabled(int num)

Is a given feature number disabled?
In order to condense the feature list, I am indexing them as numbers. This method mimics a hash table. Should probably use a real hash table, but I seem to recall browser incompatibility with this....