edu.mit.ai.psg.jevaUI
Class JevaGUI

java.lang.Object
  |
  +--java.awt.Component
        |
        +--java.awt.Container
              |
              +--java.awt.Panel
                    |
                    +--java.applet.Applet
                          |
                          +--edu.mit.ai.psg.jevaUI.JevaGUI

public class JevaGUI

extends Applet

implements ActionListener

JevaGUI is a graphical (windowed) user interface for the Jeva Java evaluator for expression & statements. JevaGUI can be used as

• an application: main starts a top read-eval-print-loop (repl) window. Good for quickly trying out some class in the classpath.
• an applet: provides a button which starts a repl window when pressed. (AWT panes haven't worked well nested in browsers.)
• a breakpoint/stub: an application may call JevaGUI.repl(..) providing an environment of current names, and a repl window appears in which the user can evaluate Java expression and statements in that environment, including calling other stubs (which create new windows), returning values, and throwing exceptions.

In any situation, results can be explored in an outline tree using Jexa, and objects found in Jexa can become parameters of statements and expressions.

Author:

CarlManning, caroma@ai.mit.edu
Copyright (c) 1997, 1998, 1999 Massachusetts Institute of Technology

See Also:

edu.mit.ai.psg.jeva, edu.mit.ai.psg.jexa, JevaUI, Serialized Form

Field Summary

static PrintWriter	err PrintWriter stream for printing errors to result pane.
static PrintWriter	out PrintWriter stream for printing to result pane.
static PrintStream	systemErr Saved system.err present when loaded
static PrintStream	systemOut Saved system.out present when loaded

Fields inherited from class java.awt.Component

BOTTOM_ALIGNMENT, CENTER_ALIGNMENT, LEFT_ALIGNMENT, RIGHT_ALIGNMENT, TOP_ALIGNMENT

Constructor Summary

JevaGUI()

Method Summary

void	actionPerformed(ActionEvent e) Start up window frame when applet button is pushed.
static Object	awaitResult(Container container) Wait for a JevaGUIFrame or JevaGUIPanel to return a value.
void	init() Applet startup: Starts a window at which users can type top level expressions.
static void	main(String[] arguments) Application Startup: Starts a window at which users can type top level expressions.
static Object	repl() Read-Eval-Print-Loop: creates a new window in which user may type java expressions and statements, including return to return a value.
static Object	repl(int options, String title, String initialMessage, Class returnClass, Class[] throwClasses, IEnv env) Read-Eval-Print-Loop: creates a new window in which user may type java expressions and statements, including return to return a value.
static void	replTop() Top read-eval-print-loop: creates a new window in which user may type java expressions and statements.
static void	replTop(int options, String title)

Methods inherited from class java.applet.Applet

destroy, 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, countComponents, deliverEvent, doLayout, findComponentAt, findComponentAt, getAlignmentX, getAlignmentY, getComponent, getComponentAt, getComponentAt, getComponentCount, getComponents, getInsets, getLayout, getMaximumSize, getMinimumSize, getPreferredSize, insets, invalidate, isAncestorOf, layout, list, list, locate, minimumSize, paint, paintComponents, paramString, preferredSize, print, printComponents, processContainerEvent, processEvent, remove, remove, removeAll, removeContainerListener, removeNotify, setFont, setLayout, update, validate, validateTree

Methods inherited from class java.awt.Component

action, add, addComponentListener, addFocusListener, addInputMethodListener, addKeyListener, addMouseListener, addMouseMotionListener, addPropertyChangeListener, addPropertyChangeListener, bounds, checkImage, checkImage, coalesceEvents, contains, contains, createImage, createImage, disable, disableEvents, dispatchEvent, enable, enable, enableEvents, enableInputMethods, firePropertyChange, getBackground, getBounds, getBounds, getColorModel, getComponentOrientation, getCursor, getDropTarget, getFont, getFontMetrics, getForeground, getGraphics, getHeight, getInputContext, getInputMethodRequests, getLocation, getLocation, getLocationOnScreen, getName, getParent, getPeer, getSize, getSize, getToolkit, getTreeLock, getWidth, getX, getY, gotFocus, handleEvent, hasFocus, hide, imageUpdate, inside, isDisplayable, isDoubleBuffered, isEnabled, 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, setCursor, 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, wait, wait, wait

Field Detail

out

public static PrintWriter out

PrintWriter stream for printing to result pane.

err

public static PrintWriter err

PrintWriter stream for printing errors to result pane.

systemOut

public static PrintStream systemOut

Saved system.out present when loaded

systemErr

public static PrintStream systemErr

Saved system.err present when loaded

Constructor Detail

JevaGUI

public JevaGUI()

Method Detail

main

public static void main(String[] arguments)

Application Startup: Starts a window at which users can type top level expressions.

init

public void init()

Applet startup: Starts a window at which users can type top level expressions.

Overrides:

init in class Applet

actionPerformed

public void actionPerformed(ActionEvent e)

Start up window frame when applet button is pushed.

Specified by:

actionPerformed in interface ActionListener

replTop

public static void replTop()

Top read-eval-print-loop: creates a new window in which user may type java expressions and statements. Returns when window is closed.

replTop

public static void replTop(int options,
                           String title)

repl

public static Object repl()
                   throws Throwable,
                          AWTException

Read-Eval-Print-Loop: creates a new window in which user may type java expressions and statements, including return to return a value.

Throws:

Throwable - --- throws anything user throws.

AWTException - if window is closed.

repl

public static Object repl(int options,
                          String title,
                          String initialMessage,
                          Class returnClass,
                          Class[] throwClasses,
                          IEnv env)
                   throws Throwable,
                          AWTException

Read-Eval-Print-Loop: creates a new window in which user may type java expressions and statements, including return to return a value.

Parameters:

options - Option flag bits or'ed together; 0 is default. Applets require JevaUI.isSuppressingSystemOutAndErrRedirectionBit and Jeva.isSuppressingPackageNameChecksBit due to security sandbox,

title - Non-null text replaces window title; helps identify window if initialMessage has scrolled away.

initialMessage - Non-null text replaces herald; if called from a breakpoint, a good practice is to show user contents of env.

returnClass - user may only return a value of this class (like method return type); Object.class allows anything. Use void.class for void result. If null, never returns (like a top level loop).

throwClasses - user may only throw Throwables which are instances of these classes, or instances of Error or RuntimeException (like method throw declarations). If null, defaults to no declarations.

env - initial environment created with Jeva.makeDefaultEnv, Jeva.extendEnv(), or Jeva.parseEval..Statement If null, defaults to Jeva.makeDefaultEnv() .

Throws:

Throwable - --- throws anything user throws compatibile with throwClasses

AWTException - if window is closed.

awaitResult

public static Object awaitResult(Container container)
                          throws Throwable,
                                 AWTException

Wait for a JevaGUIFrame or JevaGUIPanel to return a value. Called by repl after constructing and showing a JevaGUIFrame.

Parameters:

container - must be JevaGUIFrame or JevaGUIPanel