Below is my solution to this homework:
package hw5;
public class Person {
/** The person's full name */
private String name;
public enum Status {MARRIED, SINGLE, UNKNOWN, ITS_COMPLICATED};
private Status status;
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
private FriendsList friends;
private Wall wall;
public Person() {
this("",Status.UNKNOWN);
}
public Person (String name, Status status) {
this.name = name;
this.status = status;
friends = new FriendsList();
wall = new Wall();
}
public String toString() {
return name + " " + status + "\n" + friends.getNum() + " Friends:\n" + friends
+ "Wall:\n" + wall;
}
public void addFriend(Person p) {
friends.addFriend(p);
p.friends.addFriend(this); //p.addFriend would create an infinite loop
}
public void removeFriend(Person p) {
friends.removeFriend(p);
p.friends.removeFriend(this);
}
public void addWallMessage(String msg, Person author) {
if (friends.isFriend(author)) {
wall.addPost(msg, author);
}
else {
System.out.println("ERROR: " + author.getName() + " is not a friend of " + name);
}
}
/**
* Two persons are the same if they have the same name.
* @param other
* @return true if both have the same name.
*/
public boolean equals(Person other) {
return name.equalsIgnoreCase(other.name);
}
/**
* @param args
*/
public static void main(String[] args) {
Person mark = new Person("Mark Zuckerberg",Status.SINGLE);
Person cam = new Person("Cameron Winklevoss",Status.ITS_COMPLICATED);
Person tyler = new Person("Tyler Winklevoss",Status.MARRIED);
Person tyler2 = new Person("tyler winklevoss",Status.UNKNOWN);
Person peter = new Person("Peter Thiel",Status.UNKNOWN);
System.out.println(mark);
mark.addFriend(cam);
mark.addFriend(tyler);
mark.addFriend(tyler); //adding it for a SECOND time, so it does not get added
mark.addFriend(tyler2); //tyler2 does not get added because he has the same name as tyler
System.out.println(mark); //mark has 2 friends
System.out.println(tyler); //tyler has 1 friend
mark.addWallMessage("Hello there! We have a project for you!", tyler);
mark.addWallMessage("Yeah, its a Harvard-only friendster", cam);
tyler.addWallMessage("Cool, I'll work on it", mark);
System.out.println(mark);
System.out.println(tyler);
mark.addWallMessage("Hey, how is our social website coming?", cam);
cam.addWallMessage("Its going to take some time, I got finals", mark);
peter.addFriend(mark);
peter.addWallMessage("I made this cool website, want to fund me?", mark);
mark.addWallMessage("Sure", peter);
mark.addWallMessage("Wait a minute! We paid you to build that!", cam);
cam.addWallMessage("Nah hah", mark);
mark.addWallMessage("Yeah ha", cam);
cam.addWallMessage("I'm unfriending you and your twin", mark);
mark.removeFriend(cam);
mark.removeFriend(tyler);
System.out.println(mark);
System.out.println(tyler);
System.out.println(cam);
System.out.println(peter);
mark.addWallMessage("I'm going to sue you in federal court!", cam);
System.out.println(mark);
}
}
package hw5;
public class FriendsList {
private static final int MAX_FRIENDS = 1024;
private Person[] friend;
private int numFriends;
public int getNum() {
return numFriends;
}
public FriendsList() {
friend = new Person[MAX_FRIENDS];
numFriends = 0;
}
/**
* Find out if p is in here.
* @param p
* @return true if p is in this friendlist
*/
public boolean isFriend(Person p) {
for (int i=0; i < numFriends; i++) {
if (friend[i].equals(p)) {
return true;
}
}
return false;
}
/**
* Add p to list but only if it is not in here already.
* @param p
*/
public void addFriend(Person p) {
if (!isFriend(p)) {
friend[numFriends++] = p;
}
}
public String toString() {
String result = "";
for (int i=0; i < numFriends; i++) {
result += friend[i].getName() + "\n";
}
return result;
}
public void removeFriend(Person p) {
int i;
for (i=0; i < numFriends; i++) {
if (friend[i].equals(p)) break;
}
if (i < numFriends) {//p is a friend, at index i
//overwrite friend[i] with friend[i+1], and so on till the end of the list
for (int j = i; j < numFriends - 1; j++) {
friend[j] = friend[j+1];
}
numFriends--;
}
}
}
package hw5;
public class Post {
public String message;
public Person author;
public Post(String message, Person author) {
this.message = message;
this.author = author;
}
public String getMessage() {
return message;
}
public String getAuthorName() {
return author.getName();
}
}
package hw5;
public class Wall {
private Post[] posting;
private int numPosts;
private static final int MAX_WALL_POSTS = 1024;
public Wall() {
posting = new Post[MAX_WALL_POSTS];
numPosts = 0;
}
public void addPost(String msg, Person author) {
Post post = new Post(msg, author);
posting[numPosts++] = post;
}
public String toString() {
String result = "";
for (int i=numPosts-1; i >= 0; i--) {
result += posting[i].getAuthorName() + " writes:\n" + posting[i].getMessage() + "\n";
}
return result + "\n";
}
}
Posts
