iat 265 final

Procedural Language

Create data representing an image, write a procedure that can accept the data and draw it

Object Oriented Language

Create an object that contains image data AND the function to draw it (data + function in one container)

public

keyword fro access control that allows all other classes in your program to access

private

can only be accessed within the class where the member (field or method) is defined

static

keyword that specifies that the member belongs to the class instead of a specific instance

main

method drives Java applications, which is the first place the JRE visits when running your application

methods

reusable commands

methods are composed of:

method signature + (method body)

method signature is composed of

return type + method name + parameters (void main (String args[])

Parameter

place holders for values

Arguments

actual values passed in

Application Programming Interface (API)

a set of publicly accessible methods, variables, and constants of classes typically stored in a library

JFrame to JPanel?

JFrame is like the picture frame, JPanel is like the canvas

Variable

a named memory location for storing a value

3 Things You Can Do With a Variable

1. Declaration (int x; int y)

2. Initialization (x \= 20, y \= 40, first time)

3. Assignment (post initialization

Benefits of declaring data types (2)

1. what kind of value to expect

2. how to allocate space accordingly

Primitive Variable Types

an identifier for a value

1. integer (byte, short, int, and long)

2. decimal (float and double)

3. char (a, b, c, &, *)

4. boolean (true or false)

Reference Data Types

A reference to an object's memory location

1. class

2. string

3. array

4. arraylist

Class

a program entity that represents a blueprint (aka template) for a type of objects

Object

A runtime entity that combines attributes and behaviours (many ball objects, one ball class)

Interface

provides a description o fa role declared with some capabilities (via method declarations)

What kind of object do you need to use to create animations?

swing timer object

- java.swing.timer

random function that returns a number between 1 and 6

(int) (1+ Math.random() * 5));

Client Object

An object that uses another object's functionalities

2 Meanings for Encapsulation

1. an object contains within itself both attributes and behaviours

2. An object hides its data from client programs (data hiding)

getter method

method that returns the current value of a private field

setter method

method we need to change the value of a private field

How to flip a drawing when it hits an edge?

scale(-1,1);

addMouseListener can only be added to \_______?

java.awt.Component (or its subclass, JPanel is a sublcass)

Use MouseListener for?

mouseclicked()

Use MouseMotionListener for?

mouseDragged()

Adapter class

classes that provide 'dummy implementations' for all the methods declared in the corresponding interface

Array

a contiguous collection of data items of a single type

Data structure

a particular way of storing and organizing data in a computer so that it can be used efficiently

- generally used for a computer to store and fetch data at any place in its memory, specified by an address

ArrayList

a resizable array that holds objects

Benefits of Graphics2D (3)

- It draws or fills primitives in a more flexible way

- It can draw more primitives than its parent class, e.g. curves

- It has functionality for checking intersection and containment between objects

shape

a geometric object passed in as argument, rather than coupled with method name

- e.g draw (shape)

fill (shape)

Ellipse2D, Rectangle2D, Arc2D etc are \_______ classes

abstract

When do you use the setter methods for the geom class?

1. during initialization

2. when properties of an object being modelled have changed

Search algorithm

about searching for an item in a list per some criteria: largest to smallest etc

Linear search algorthm

1. declare variable s for holding smallest and initialize it with the first element

2. interate through the rest of the elements and compare

Rule of Thumb 1

Make active object call if it runs against inactive objects that typically doesn't alter its state/behaviour (e.g boundary detection)

Rule of Thumb 2

Make the controller (panel object) call for the following scenarios:

- Two objects of different types (active vs. passive), both change state/behavior with collision

- Two active objects of the same type, only one changing state/behavior

Nested loop

putting one loop inside another

Encapsulation (2 meanings)

- An Object contains both attributes and behaviors

- An Object hides its data from client programs

2 Methods to Use Data hiding

- Use private keyword to hide fields

- Use public getter/setter methods to allow access to fields when necessary

Inheritance

child class inherits all of its parent class' attributes and behaviors and also extends its functionality

2 reasons for inheritance

1. code reuse

2. extension

this

a keyword that refers to the current object itself: a way to say "me" or "myself" by an object

super

a keyword that refers to the superclass portion of an object

Overriding Polymorphism

A subclass can redefine any of its parent class' methods with the same signature

More than one implementation

Polymorphism

The ability to create a variable or method that has more than one form

Inclusion polymorphism

A single variable can be used to reference an object of different classes that are connected by inheritance - a variable has more than one form

Finite State Machine (FSM)

commonly used in AI programming for creating variations of behaviour

A number of states and transitions between them based on conditions

Focus (for keyboard inputs)

you or the system has selected a particular component to be active to receive keyboard input

Code Pull up

pull fields or methods up to their superclass, or remove the redundant fields or methods from subclasses

Inheritance by Interface

allows us to group dissimilar classes of objects that are related only be certain common behaviour(s)

Interface allows for \_______ inheritance

multiple inheritance, whereas you can only extend one subclass or abstract class

Abstract class should be used with polymorphism when . . .

objects have common properties and even a common behaviour (draw)

Rule of abstract methods

any subclass that extends an abstract class must implement all the abstract methods it has declared

Why use abstract class and not interface?

you may need the parent class to hold some common properties and also define some common methods (other than those abstract ones), where an abstract class can do but an interface cannot

Compiler error

errors that compiler can catch - easy to fix

Semantic errors

Your program doesn't do the right thing