Java Classes

Simple Input

A Java class for getting input into a program in a simple manner. The class has methods such as getInt(prompt) or getString(prompt), which pop up an input window and return the result.

Author(s): Bruce Quig (bruce.quig@infotech.monash.edu.au) , Michael Kölling (mik@mip.sdu.dk).

Submitted by: Michael Kölling

Known uses: I have used this class very successfully in a first assignment in first semester (before other forms of input were introduced). Once students understand method calls, it is very straight forward to use.

Hints for use: Save the source file, then use the "Import Class" function in BlueJ to import this class into your project. Then it can be used like any other class.

See also: -

Link(s): SimpleInput.java (right-click or shift-click to save)

GUI/CUI - input classes

Modified and extended version of the SimpleInput class (above). It now accepts all nine fundamental variable types - : byte, short, int, long, float, double, char, String, and boolean . It ignores appropriate input errors smartly. It also gives a easy way to generate output through dialog boxes.

The file is named as gui.java , and accompanying testguinput.java uses it as a sample program.

Also includes a cui class which does the same thing through console input. The method formats are same for both cui and gui class. The accompanying file testcuinput.java uses it as a sample program.

Some highlights are : ( Applicable to both gui and cui classes )

• If someone wants to input a integer type data into variable b , he simply writes: b = s1.getInt("Enter an integer no..."); s1 is the object generated from class gui/cui - say, gui s1 = new gui( );
• If he wants to turn on the built in error correction code, he simply writes: s1.ecc ( true ); The default is false, if not mentioned , if made on , it ignores integer input error like 34p5 ( makes it simple 345 ).
• If he wants to output something , say value of variable b, he simply writes: s1.show("You have entered : Byte = "+b) ;

Author(s): Shirshasin Ghosh (shirsha@reach2net.com)

Submitted by: Shirshasin Ghosh

Known uses: I have used these classes very successfully to first level students in Calcutta (before other forms of input were introduced). Once students understand method calls, it is very straight forward to use.

Hints for use: Save the source file, then use the "Import Class" function in BlueJ to import this class into your project. Then it can be used like any other class.

See also: The accompanying testguinput.java , and testcuinput.java files. These use the classes as a sample program.

Link(s): gui.java cui.java testguinput.java testcuinput.java (right-click/Save... to save the files)

Canvas

A Java class for drawing into a window. This class provides output only (no events). It can be used to produce drawings and animations. Very simple to use.

Author(s): Bruce Quig (bruce.quig@infotech.monash.edu.au), Michael Kölling (mik@mip.sdu.dk).

Submitted by: Michael Kölling

Known uses: I have used this class for a second semester assignment. Students implemented simulations (such as a lift simulation) and used this class to produce animated output.

Hints for use: Save the source file, then use the "Import Class" function in BlueJ to import this class into your project. Then it can be used like any other class.

See also: The Bouncing Ball example in the Demonstrations section demonstrates the use of this class.

Link(s): Canvas.java (right-click or shift-click to save)

stdio

stdio defines static methods for using typed input from the console window. This class includes two methods for getting a line of input, two methods for handling (i.e. parsing) typed-in numbers, and a simple rounding method so that System.out.println won't print "0.33333333333333333" when you want to see "0.33".

Author(s): Michael Trigoboff (mltsoftware@comcast.net)

Submitted by: Michael Trigoboff

Known uses: I have used this class successfully as a way to let my students produce command-line applications that they can run in a MS-DOS command line window. This lets them get started without first having to climb the learning curve for Java GUI programming (AWT and Swing).

Hints for use: Put stdio.java and stdio.class into your project folder and then use stdio in your project as you would use any other class.

See also: -

Link(s):

stdio.java (the source file, right-click or shift-click to save)
stdio.class (the compiled class file)
stdio.html (javadoc format documentation for stdio)
StdioTest.java (a small example program for using stdio)

stdio.jar (all of the above together in a single jar file)

GWindow

An implementation of a GUI window (JFrame) to test AWT/Swing components and graphics primitives. From the documentation: "This window will work properly if opened from within a JAR file that is executed from the DOS command line because it provides a method that allows a thread to wait until the window is closed."

Author(s): Michael Trigoboff (mltsoftware@comcast.net)

Submitted by: Michael Trigoboff

Known uses: I have used GWindow successfully as a way to let my students run and test code that uses Java graphics primitives. It is also a way to test AWT and Swing user interfaces without incurring the debugging limitations caused by using an applet.

Hints for use: See GWindowDemo for an example of how to use GWindow.

See also: -

Link(s):

gwindow.jar (the jar file contains the GWindow class, the demo class and documentation)

User comments:

No comments submitted.
Add your own comment.

AppletWindow

AppletWindow is a window framework that lets you run applets in a normal JFrame. This allows you to use the BlueJ debugger on your applet.

Author(s): Michael Trigoboff (mltsoftware@comcast.net)

Submitted by: Michael Trigoboff

Known uses: Run an applet in a JFrame-based window.

Hints for use: The .jar file includes a simple demo class and a simple applet. See the README.TXT file for complete instructions.

See also: -

Link(s):

appletwn.jar (includes a simple demo class and a simple applet)

Skodak's IO Helper for BlueJ

"Skodak's IO Helper for BlueJ" is designed specially for BlueJ IDE to support teaching of basics of  IO operations in Java. It is suitable for any other IDE or standalone execution of applications. It is not designed for Java applets.

More information is on the web page.

Author(s): Petr Skoda (petr.skoda@vslib.cz)

Submitted by: Petr Skoda

Known uses: -

Hints for use: -

See also: -

Link(s): Skodak's IO Helper web page

Turtle Graphics

This is an implementation of the good old turtle graphics package. Source code for the turtle library is available in English and German, and some examples are available (with German comments).

Author(s): Alfred Hermes (a.hermes@fz-juelich.de)

Submitted by: Alfred Hermes

Known uses: -

Hints for use: -

See also: -

Link(s):

Turtle.zip (turtle library source code, German)
BlueJTurtle.zip (some examples of using the turtle, German)
TurtleE.zip (turtle library source code, English)
BlueJTurtleE.zip (some examples of using the turtle, English)

JEWL

JEWL is GUI library for beginners which allows GUI-based programs to be used from the "Hello world" stage onwards.

Author(s): John English (je@brighton.ac.uk)

Submitted by: John English

Known uses: -

Hints for use: -

See also: -

Link(s): http://www.it.brighton.ac.uk/staff/je/java/jewl