Exercise Set: Implementing an Object-Oriented Design

Transcription

1 Exercise Set: Implemetig a Object-Orieted Desig I this exercise set, we have marked questios we thik are harder tha others with a [ ]. We have also marked questios for which solutios are provided at the ed of the set ([SP]). To check solutios for other questios tha those marked with [SP], ask oe of the istructors or TAs or post a questio to the google group! Social Network Applicatio Give the followig partially specified requiremets for a social etwork applicatio Foomix ad the Object- Orieted UML Class Diagram: The Social Network Applicatio Foomix allows frieds to coect with each other olie ad share iformatio such as their photo albums or movies. Foomix allows a user to register ad fill i persoal iformatio. I particular, it lets the user specify her ame, birthday, address ad a profile picture. Oce registered, a user ca create photo albums that each has a list of pictures that the user has uploaded to Foomix. The user ca also upload movies to his profile. For each uploaded cotet, Foomix stores the time whe the cotet was added. Each user has frieds he is coected to ad ca add more users as frieds. For this, a user ca list all or search for users registered with the FoomixNetwork. Foomix also provides a marketplace that offers a variety of games a user ca play. FarmTow ad MafiaStruggle are two of these games. New games ca be added ay time to the marketplace. Oce a user plays oe of the offered games, the game remembers the user ad its highest score i a rakig. Furthermore, users ca rak the games.

2 frieds FoomixNetwork MarketPlace adduser(user : User) 1 1 addgame( 1 1 game : Game) 1 User ame : Strig birthday: Date addcotet( cot : Cotet) 1 1 Cotet Address cityname : Strig provice : Strig coutry : Strig FarmTow Game MafiaStruggle ProfilePicture timeadded: Date Picture PhotoAlbum Movie 1. Implemet the desig i Java. Therefore: a) implemet the classes (describe what packages you would create ad what classes go i them); b) implemet the associatios (do t forget to implemet getter ad setter methods; ote, I already partially specified three setter methods i the desig, adduser, addapplicatio ad addcotet). [ ] 2. Thik about the types of collectios from the Java Collectios Framework you would use to implemet the relatios ad describe why. I particular, thik how you would implemet the user rakigs i a Game. 3. Implemet equals ad hashcode methods for type User (check the readig to make sure you did t forget aythig). [SP] 4. Implemet Comparable for pictures i a photo album so that the pictures will be sorted by the timeadded whe Collectios.sort( ) is used o a collectio of Pictures

3 5. Implemet Comparable for type User so that user profiles ca be sorted by the Address (i alphabetical order first by coutry, the by provice ad last by city ame, e.g. a user from BC, Caada would be after a user from Alberta, Caada, but before a user from Bavaria, Germay). Therefore, delegate the compariso to Address. (Delegatio is described i the GUI readig ubc-cpsc-210-gui.pdf o pages 3-5) [ ] 6. Create a class MemoryLeakDemo ad copy the followig code ito the class. [ ] Note: Make sure you have the followig costructors i your implemetatio: FoomixNetwork(), MarketPlace(), Game(Strig ame), User(Strig ame, java.util.date birthday), ad Cotet(java.util.Date timeadded). a) Ru the Eclipse Memory Aalyzer Tool (MAT) o memory dumped from the MemoryLeakDemo program ad determie which objects are takig most space. b) Draw a object referece graph for the code below ad the oe you implemeted startig from the mai method. public static void mai(strig[] args) { FoomixNetwork f = ew FoomixNetwork(); addmarketplaceadgames(f); addusers(); public void addmarketplace(foomixnetwork f) { MarketPlace mp = ew MarketPlace(); // check i your implemetatio that you called the setter // setmarketplace i the FoomixNetwork, otherwise chage the method i here f.setmarketplace(mp); addgames(f); addusers(f); public void addgames(foomixnetwork f) { // make sure i your implemetatio that you called the getter getmarketplace // i the FoomixNetwork, otherwise chage the method i here for (it i=0; i<100; i++) { f.getmarketplace().addapplicatio(ew Game("Game "+i)); public void addusers(foomixnetwork f) { for (it i=0; i<100; i++) { adduser(f,i); public void adduser(foomixnetwork f, it j) { List<Date> dates = ew ArrayList<Date>(); Date bday = ew Date(); Bday.setYear(bday.getYear() - j); for (it i=0; i<1000; i++) { User user = ew User("David",bday); f.adduser(user);

4 dates.add(ew Date()); Cotet album = ew PhotoAlbum(dates.get(i)); user.addcotet(album);

5 SOLUTIONS: public boolea equals(object obj) { if (obj == ull getclass()!= obj.getclass()) retur false; User other = (User) obj; retur getname().equals(other.getname()) && getbirthday().equals(other.getbirthday()) && public it hashcode() { it result = 17; result = 37*result + getname().hashcode(); result = 37*result + getbirthday().hashcode(); result = 37*result + getaddress().hashcode(); retur result;