1. Inheritance, Abstract & Interface Pepper With help from http://docs.oracle.com/javase/tutorial/java/IandI/super.html and http://www.cis.upenn.edu/~palsetia/java/Animal/index.shtm l

2.  Seeing Eye Dog is a dog  Properties: In addition to being a dog with a name, isAwake and position states, it has a tracking code  Actions: In addition to being able to makeNoise, sleep and wake, it can get its trackingcode and sit to warn for a curb. Dog Class + Special type of Dog Credit to: http://www.cis.upenn.edu/~palsetia/java/Animal/index.shtml

3. Make sub-classes (put "extends " classname after class) http://home.adelphi.edu/~pe16132/csc171/notes/fangstuf f/Wackadot.java  Can use the entire extended class  Can override methods  Can see all protected and public methods and variables  Can choose to execute methods from the super class using super.methodname  http://docs.oracle.com/javase/tutorial/java/IandI/super.html http://docs.oracle.com/javase/tutorial/java/IandI/super.html Class Extension

4. public class Dog { private String name; private Boolean isAwake; private String position; public Dog (String name){ this.name = name; this.isAwake = true; this.position = "standing"; } public String makeNoise(){ return "bark"; } public void sleep(){ this.isAwake = false;} public void wake(){ this.isAwake = true;} public void sit(){ this.position = "sit";} } Dog Class + Special type of Dog Credit to: http://www.cis.upenn.edu/~palsetia/java/Animal/index.shtml public class SeeingEyeDog extends Dog { private String trackingCode; public SeeingEyeDog(String name, String trackingCode){ super(name); this.trackingCode = trackingCode; } public String getTrackingCode(){ return this.trackingCode;} public String sitForCurb(){ super.sit(); super.makeNoise();} }

5.  SeeingEyeDog can be placed into Dog or SeeingEyeDog variable type  When in Dog type, it cannot get the tracking code public class DogDriver { public static void main(){ Dog pepperPet = new Dog("Olive"); Dog working1 = new SeeingEyeDog("Sarah","ABC"); SeeingEyeDog working2 = new SeeingEyeDog("Coco","ABCD"); System.out.println (pepperPet.makeNoise()); System.out.println (working1.makeNoise()); System.out.println (working2.getTrackingCode()); // System.out.println (working1.getTrackingCode()); wont work if (working1 instanceof SeeingEyeDog){ SeeingEyeDog temp = (SeeingEyeDog) working1; System.out.println(temp.getTrackingCode()); }}} Extended Class Used by Driver

6.  Make one player  Constructor – starts on square 1 and has a name  Roll dice  Say he is joining the game  Extend to different player types  Zorgon - some number of eyes as well  Override a method: He has a different message to say he is joining the game. He tells of his powers  Extra method: ability to jump ahead the same number of squares as eyes.  Example:  http://home.adelphi.edu/~pe16132/csc171/presentation s.html http://home.adelphi.edu/~pe16132/csc171/presentation s.html Player Extension

7.  Can only extend one class  A seeing Eye Dog is a dog, but it is also a trainable being  Use Interface of trainable beings  Both the super and subclass can have objects created.  Problem: Animals share methods and properties, but cannot exist without being a specific type of animal such as Dog or Cat.  Use abstract class of Animals Extension Limits

8.  Cannot create its own object  Can contain abstract classes, which every extender must code - compiler complains if the lower class does not implement it.  http://docs.oracle.com/j avase/tutorial/java/Iand I/abstract.html http://docs.oracle.com/j avase/tutorial/java/Iand I/abstract.html Abstract Classes

9. public class Dog extends Animal { private String position; public Dog (String name){ super(name); this.position = "standing"; } public String makeNoise(){ return "bark"; } public void sit(){ this.position = "sit";} public String eats(){ return "Meat and whatever else I find";} } Abstract Class and its extensions public abstract class Animal{ private String name; private Boolean isAwake; public Animal (String name){ this.name = name; this.isAwake = true; } public void sleep(){ this.isAwake = false;} public void wake(){ this.isAwake = true;} public abstract String eats(); } public class Fish extends Animal { private boolean isSwimming; public Fish(String name) { super(name); this.isSwimming = true; } public String eats(){ return "little fish and algae";} }

10. public class AnimalDriver { public static void main(){ Animal[] myAnimals = new Animal[2]; myAnimals[0] = new SeeingEyeDog("Sarah","ABC"); myAnimals[1] = new Fish ("James"); System.out.println (myAnimals[0].eats()); System.out.println (myAnimals[1].eats()); if (myAnimals[0] instanceof SeeingEyeDog){ SeeingEyeDog temp = (SeeingEyeDog) myAnimals[0]; System.out.println(temp.getTrackingCode()); } Animal Driver uses Abstract Class

11.  More limits  Cannot extend two classes  Trainable  Animal  Interface Interfaces

12.  Can create a type that has only abstract methods, with no properties.  Basically a contract to implement interfaces  Contains method headers with no code below it.  Lower classes can implement many interfaces (but only extend one class)  Implementing an interface means you promise (and the compiler checks) that you will implement the methods listed.  For our pets, trainable could be an interface containing the methods sit and stand and stay.  http://docs.oracle.com/javase/tutorial/java/IandI/interfac eDef.html http://docs.oracle.com/javase/tutorial/java/IandI/interfac eDef.html Interface

13.  Extension: To have all properties and method of super class in the sub class  Add extends to the subclass  Can override methods inside a subclass  Cannot access anything private in the class  Use super to use superclass methods if overridden  Abstract: To hold common code you want to extend  Cannot be used to create instances  Can insist method names be implemented  Interface: To insist method names be implemented  Cannot be used to create instances  Cannot have properties  Cannot code methods, only their headers Summary - Class Types