JAVA Coding, Programing

1. Java
Programming(for designers)

2. What is a Program?
A list of detailed instructions that the computer
carries out
To make a cup of coffee the
following would not be sufficient:
The instructions would have
to be much more detailed:
You have to say exactly what to do in the right order with no ambiguity
1. Boil water
2. Put coffee in cup
3. Pour in hot water
4. Add milk
1.1. Go to kettle
1.2. Check kettle has water in it
1.3. If not
1.3.1 Take kettle to cold tap
1.3.2 Remove lid of kettle
1.3.3 Put kettle under cold tap
1.3.4 Turn on tap
1.3.5 When kettle full turn off tap
1.3.6 Return kettle to worktop
1.4. Plug kettle into mains
1.5.Switch on electricity
…….

3. Java is…
• Platform-independent
• Apps for mobile phones and other consumer
devices
• Secure, portable, multithreaded
• Online, server-side applications
• Simple, Object oriented
• GPL libraries
X
X
X?
☺
X
☺

4. Get started
• Two components:
• Java Virtual Machine (VM)
• Base for the Java platform, install Win version
• Java Application Programming Interface (API)
• Prewritten code, organized into packages of similar
topics. Each package or library contains classes and
interfaces that you can call and extend. Example:
• Rectangle2D = new Rectangle2D(loc, width, height)
• http://java.sun.com/learning/new2java

5. Acronyms
• JDK or J2SE, Development Kit
• Set of Java development tools, consisting of the
API classes, a Java compiler, and the Java virtual
machine (VM) interpreter
• The JDK is used to compile Java applications and
applets. The most current version is the J2SE 5
• J2SE, Runtime Environment 5.0

6. Set up: Download the JDK
• And set the classpath in Windows
Include the directories
where you will run
Java apps

7. Set Up a Development
Environment
• NetBeans IDE, JEdit, Eclipse, JCreator
• Or use a simple text editor, and compile and
run from the command line

8. Set Up
• Download J2SE 5.0 Documentation
• Look for useful libraries

9. Some Useful Libraries
• Colt: or High Performance Scientific and Technical Computing
• Weka 3: Data Mining Software in Java
• JHotDraw is a two-dimensional graphics framework for structured
drawing editors
• JGAP is a genetic algorithms component written in the form of a
Java package
• OpenAI: a full suite of Artificial Intelligence components: Agents,
Neural Nets, GAs…
• JUNG:Java Universal Network/Graph Framework
• JOONE: JGAP's genetic algorithms to evolve neural nets
• HyperGraph: to work with hyperbolic geometry and especially with
hyperbolic trees
• Repast: an agent modeling toolkit (like Swarm)
• JExcel or JXL provides the ability to read, write, and modify
Microsoft Excel spreadsheets

10. Standard Java Libraries
• Language
• Maths
• Graphics
• 2D
• 3D
• File I/O
•JAI: Advanced
Networking
•Imaging
•XML
•Print

11. Swing
• GUI-control (widget) library in Java 2
• Built-in controls, flexible and customizable
• Features aimed at interface design
• Buttons, tabbed panes,
dockable toolbars,
scroll panes, tooltips,
tables, etc.
• Look & feel can be changed

12. Java 2D
• Standard drawing library in Java 2
• Drawing attributes
• Fill patterns and images
• Fonts
• Line thicknesses and dashing patterns
• Colour mixing rules and transparency
• Transformations
• Floating-point coordinate system
• Mapping from memory coords to
screen or printer coords
• Affine transforms: translate, scale,
rotate, and shear

13. Java 3D
• Extension to Java
• Not part of “core” Java language like Java 2D
• Built on Direct3D or OpenGL, depending on
platform
• Scene-graph based model, not primarily
immediate-mode rendering

14. Java Versions
• Java 1.0, 1.1… “Java 2” refers to 1.2 onwards
• Popular: 1.4.2
• New: 1.5. The leading "1." is dropped, now it
is Java Platform Standard Edition 5.0
• But… version 5.0 also keeps the version
number 1.5.0 in some places visible only to
developers
• This release is also known as “Tiger” (not the latest Mac OS X!)

15. Jargon
• Application is a stand-alone Java program
• Applet is a browser-based Java program

16. Basic Procedure
1. Write a .java file
2. Compile it with the javac command
3. Now you have a .class file
4. Run it with the java command
5. Voilá!

17. Running a Java
ApplicationWrite
Java
code
javac MyProg.java
java MyProg
Java code:
MyProg.java
Bytecode:
MyProg.class
IDE or
Text
Editor
Output
Save the file
with a .java
extension
Run the
Java
compiler
'javac'
Execute the
bytecode with the
command 'java'
This creates
a file of
bytecode with
a .class
extension User to interact
with the system
Program to
execute and
produce a data
set, graphs, etc.

18. Java program layout
• A typical Java file looks like:
import java.awt.*;
import java.util.*;
public class SomethingOrOther {
// field and method definitions
. . .
}
This must be in a file named
SomethingOrOther.java !

19. What does it mean?
import java.awt.*;
import java.applet.Applet;
public class Greetings extends Applet {
public void paint(Graphics g) {
g.drawString("Hello World!", 50, 50);
}
}
These 2 lines tell the computer to include
(import) two standard libraries awt (Abstract
Window Toolkit) and applet.
This line tells the
computer to display
some text (a string) on
the screen.
This line announces that the
program (class) can be run by
anyone (public), is called
Greetings and is an Applet.
This line
declares what
follows in the {
} as a method
called paint.
This is where it is displayed in
pixels across and down from the
top left hand corner
This is what is displayed

20. A Java Class
• Java programs are collections of classes
• OOP:
• A class that represents a rectangle would contain
variables for its location, its width, and its height
• The class can also contain a method that
calculates the area of the rectangle
• An instance of the rectangle class could contain
the information for a specific rectangle, such as
the dimensions of a room

22. An Applet is a Panel is a
Container… is an Object
java.lang.Object
|
+----java.awt.Component
|
+----java.awt.Container
|
+----java.awt.Panel
|
+----java.applet.Applet
…so you can do things with it that you’d do with
applets, panels, containers, components, and objects.

23. Object Oriented (OO)
Programming
A key aspect is Inheritance.
You don’t have to describe similar objects completely. You
can define a superclass (sometimes called base class) that
has the common attributes and methods and inherit these
adding only the ones that are different.
Vehicle
Bus Lorry
Attributes: Speed, Colour
Methods: Start, Stop
Attributes:
Max Load
Methods:
Pick up Load
Attributes: Max
Passengers
Methods: Pick up
Passengers
These are inherited

24. What classes, why?
• A file can contain multiple classes, but only
one can be declared public, and that one’s
name must match the filename
• Usually 1 class = 1 file
• Most difficult part is to plan the program: the
classes, the methods, the variables, the
procedure
• If you can define it in paper & pencil, the rest is
easy

25. Methods
• Define a group of statements that perform a
particular operation
• With or without arguments
calculateArea(shape) {
// here geom operations
}
createShape() {
// new square...
// calculateArea(square)
}

26. Primitives and Objects
• Java distinguishes two kinds of entities
• Primitive types
• Objects
• Primitive types: integers, doubles, booleans,
strings…
• Objects are associated with reference
variables which store an object’s address

27. Expressions
• Assignment statements: =, +=, *= etc.
• Arithmetic uses the familiar + - * / %
• Java uses ++ and --
• Java has boolean operators && || !
• Java has comparisons < <= == != >= >

28. Control statements
if (x < y) smaller = x;
if (x < y){ smaller=x; sum += x;}
else { smaller = y; sum += y; }
while (x < y) { y = y - x; }
do { y = y - x; } while (x < y)
for (int i = 0; i < max; i++)
sum += i;

29. The main method
• Every Java application must contain a main
method:
• public static void main(String[] args)
• An application executes the main method
first. The array of Strings can be empty or it
can receive arguments to customise how the
program runs (number of iterations, number
of agents, etc).

30. Example
An Evolutionary Design System

38. public static void main(String[] args) {
new Model();
}
public Model() {
EvoDesign frame = new EvoDesign();
frame.setVisible(true);
}

39. public EvoDesign() {
jbInit();
}
private void jbInit() throws Exception {
setSize(new Dimension(860,680));
setTitle("Evolutionary Design");
jMenuFile.setText("File");…
setJMenuBar(jMenuBar);
JComboBox jGens…
JList jListFns…
JButton jRun…
jTabs.addTabs…
contentPane.add(…);
}
void jTabs_clicked(ChangeEvent e) { … }
void jLists_mouseClicked(MouseEvent e) {
… }

40. Image makeFitnessLines(Image im) {
LineGraph bg = new LineGraph();
bg.setDefaultLineThickness(0.1);
…
try {
new ImageOutput(im);
out.render(bg); im = out.getImage();
}
}
void jMenuExit_actionPerformed(ActionEvent e) {
System.exit(0);
}
class drawPanel extends JPanel {
public void paint(Graphics g) {
g.setFont(EvoDesign.myFont);
g2.drawImage(new BufferedImage(0, 50, 2);
}
}

41. public void setupGA() throws Exception {
fitnessHistory = new DoubleArrayList();
topFitness.clear();
Configuration conf = new DefaultConfiguration();
conf.addGeneticOperator( new MutationOperator(mut) );
conf.addGeneticOperator( new CustomCrossover(cross) );
FitnessFunction myFunc = new FitnessFn(chrom);
conf.setFitnessFunction(myFunc);
Gene[] g = new Gene[chrom];
g[0] = new BooleanGene();
g[i] = new IntegerGene(1, alle);
Chromosome sampleChromosome = new Chromosome(g);
conf.setSampleChromosome(sampleChromosome);
conf.setPopulationSize(EvoDesign.pop);
genPopulation = Genotype.randomInitialGenotype(conf);
Chromosome best = genPopulation.getFittestChromosome();
}

42. public FitnessFn(int a) {
}
public int evaluate(Chromosome a) {
int fitness = 0;
Gene[] gs = a.getGenes();
if (EvoDesign.fnCrit.equals("minMean")) {
fitness += ( EvoDesign.alle -
Descriptive.mean(sd) );
}
return Math.max(1, fitness);
}

43. public Colours01() {
setColorPalettes();
}
public static BufferedImage
makeOutputImage() {
for (int i = 0; i < topSolutions.size(); i++) {
Chromosome s = topSolutions.get(i);
for (int j = 0; j < s.size(); j++) {
Gene si = s.getGene(j);
g2.setColor( getAllele() .intValue());
g2.fillRect(boxX, boxY, stepX, 25);
}
}
return bf;
}

44. Code
• Get these slides and the source code for the
example at:
http://www.arch.usyd.edu.au/~rsos7705/programming.html