Java Spring 2010

PImage Let’s look at the PImage class in ProcessingPImage –What are the fields (i.e., variables)? –What methods are available? –What about the constructor---how many parameters does it have? There are 4 constructors each with a different number of parameters

PImage Revisited Here’s an alternative way of looking at the documentation for PImagePImage This documentation is produced by Javadoc Javadoc Processing is implemented as a set of Java classes that accompany those normally provided with Java Can you find the line() method?

Java Java is a programming language developed by Sun Microsystems in Java is one of the first languages to be platform independent. –Java is compiled to byte-code that runs on a Java interpreter A Java program never executes directly (i.e., natively) on a machine; instead the Java interpreter reads the byte code and executes the corresponding native machine instructions. To run Java programs on a computer, all that is needed is the interpreter (java virtual machine) and some library routines (the API)

Ways to run Java Java is rarely run as an “application” –Such as for forecasting weather Applet –Runs within a browser window –Superclass of Processing PApplet Web application –Runs on a web server Javascript is not Java

The Java API The Java API is the code that comes with the java interpreter (a.k.a. the java virtual machine) when you download java. The java API is a collection of Java classes---take a look at the API for Java 6 (aka 1.6)API for Java 6 (aka 1.6) See if you can find the String class.

Running Java outside of Processing If the instructor is so inclined, you’ll be show how to run the following exciting Java application under a Java IDE Otherwise, you’ll just look at the code. (Or maybe not even that.)

Pets public class Pets { /* Creates a Cat and a Dog */ public static void main (String [] args) { Cat tom = new Cat (); // create Cat object Dog spike = new Dog; // create Dog object // demonstrate Cat behavior tom.bite (spike); System.out.println (); // Skip a line of output // demonstrate Dog behavior spike.beenBittenBy (tom); }

The cat public class Cat { public void hiss () { System.out.println ("Hiss!"); } public void scratch (Dog victum) { System.out.println ("I'm scratching the dog"); victum.growl (); } public void bite (Dog sillyDog) { System.out.println ("I'm bitting the dog"); sillyDog.yelp (); scratch (sillyDog); }

The Dog public class Dog { public void bark () { System.out.println ("Arf!"); } public void growl () { System.out.println ("Grrrr!"); } public void yelp () { System.out.println ("Awooo!"); } public void beenBittenBy (Cat sillyCat) { System.out.println("I've been bitten by a cat with a mean hiss:"); sillyCat.hiss (); }