Java Intro Chris North cs3724: HCI

Presentations john randal, tom shultz Vote: UI Hall of Fame/Shame?

Quiz Visualization design principles: show me the data Increase info density Overview first, zoom&filter, details on demand … How to map data to graphics? 1. Data items become marks 2. Data values map to mark attributes

More Quiz Multi-dimensional data? multiple attributes Types of scale in multi-dim data? # points # attributes ranges of data values 3 multi-dim visualizations? par coords Spotfire: mapping, brush&link, DQ Tablelens: graphical table

Data Scale # of attributes (dimensionality) # of items # of possible values (e.g. bits/value)

Spotfire Multiple views: brushing and linking Dynamic Queries Details window

TableLens (Eureka by Inxight) Visual encoding of cell values, sorting Details expand within context

Parallel Coordinates (XmdvTool)

Par coords: attrs, <1000 points Tablelens: attrs, 1000, more by grouping Spotfire: 10 attrs, more w/ DQ, 100,000 pts

Homework #2: Info. Vis. Tools Get some data: Tabular, >=5 attributes (columns), >=500 items (rows) Use 2 visualization tools + Excel: Spotfire, TableLens, Parallel Coordinates Mcbryde 104c 2 page report: Discoveries in data Comparison of tools Due: Feb 19: A-K Feb 21: L-Z

Technologies VisualBasic Fast prototyping Help stinks Lack of control, multi-threading, POWER! Code tends to be ugly, variation, arbitrary Java Power Lots to learn Slow development, except jbuilder? Complexity Tons of code Help is good

Java materials Java 2 = sdk 1.2 or better Documentation: Tutorials, reference, API Sams “Teach yourself Java2 in 21 days” Borland JBuilder 6 Free! Cross between VB and VC++

Java differences Basic statements identical to C++ Object-oriented only! No.h files Garbage collection: no delete No pointers (object references only) GUI: AWT, Swing Applet/application Single inheritance, interfaces Packaging No global vars Error Handling, exceptions (try, catch) E.g. Array bounds checking Security Objects, components

Java compiling Code: myclass.java (text file) Compile: javac myclass.java Creates: myclass.class(byte code) Run: java myclass Java virtual machine, interpets/compiles (machine code) Packaging: jar Or use JBuilder, like VC++

Java Applications Run from command line, like.exe HelloWorldApp.java: Class helloWorld { public static void main(String[] args){ system.out.println(“Hello World!”); } javac HelloWorldApp.java Java HelloWorldApp Hello World! Can be main( ) in any/all classes

Java Applets Run in a web browser, like.ocx control HelloWorldApplet.java: Import java.awt.* public Class helloWorld extends javax.swing.JApplet { public void init(){ setBackground(Color.white); } public void paint(Graphics g){ g.setColor(Color.black); g.drawString(“Hello World!”, 10,10); } javac HelloWorldApplet.java appletviewer HelloWorldApplet Hello World!

Java Applets HelloWorldApplet.html: Need java. Put.html and.class on website Java plug-in Hello World!

Applet Methods init( ) - initialization start( ) - resume processing (e.g. animations) stop( )- pause destroy( )- cleanup paint( )- redraw stuff (‘expose’ event)

Applet Security No read/write on client machine Can’t execute programs on client machine Communicate only with server “Java applet window” Warning Certificates

JBuilder

Upcoming Java Topics GUIs: Swing, AWT, MVC Event handling, listeners Graphics Animation, threads Components, JavaBeans Databases, JDBC

Next Midterm: feb 26, tues Presentations: proj1 design or UI critique Next Tues: mohamed hassoun, aaron dalton Next Thurs: nadine edwards, steve terhar

Project 2: Java Teams due today Get started on design 0: form teams of 3 (feb 14) 1: design(feb 28) 2: initial implementation(mid march) 3: final implementation (early April)