P07 Twitter Feed
P07 Twitter Feed Pair Programming: NOT ALLOWED
CS 300: Programming II – Spring 2023 Due: 11:59 PM CDT on WED 04/12
P07 Twitter Feed
Overview
Thanks to a controversial deal, the world has been watching popular microblogging platform Twitte
slowly catch on metaphorical fire. If you’re somehow unfamiliar, Twitter collects short posts (280
characters or less) which other users interact with by liking or retweeting.
A classic 2012 tweet from Twitter user @dril
In this program, you will model a simple Twitter feed as a linked list of tweets. You will be able to iterate
through these tweets in reverse-chronological order, or show only tweets from users with important
lue checkmarks, or with only tweets with more than a certain ratio of likes to total interactions
Grading Ru
ic
5 points Pre-assignment Quiz: accessible through Canvas until 11:59PM on 04/10.
15 points Immediate Automated Tests: accessible by submission to Gradescope. You will
eceive feedback from these tests before the submission deadline and may make
changes to your code in order to pass these tests.
Passing all immediate automated tests does not guarantee full credit for the
assignment.
20 points Additional Automated Tests: these will also run on submission to Gradescope, but
you will not receive feedback from these tests until after the submission deadline.
10 points Manual Grading Feedback: TAs or graders will manually review your code, focusing
on commenting and style.
©2023 Mouna Kacem, Ho
es LeGault — University of Wisconsin–Madison
1
P07 Twitter Feed Pair Programming: NOT ALLOWED
CS 300: Programming II – Spring 2023 Due: 11:59 PM CDT on WED 04/12
Learning Objectives
After completing this assignment, you should be able to:
● Explain how data is stored in a singly-linked list, including how additional elements are added in
locations other than the head or tail of the list
● Contrast multiple different approaches to implementation of the Iterator interface
● Identify the ways in which an Iterable class can be used
Additional Assignment Requirements and Notes
● Pair programming is NOT ALLOWED for this assignment. You must complete and submit P07
individually.
● The ONLY external li
aries you may use in any of your classes are:
java.util.Calendar, java.util.Date
java.util.Iterato
java.util.NoSuchElementException
Use of any other packages (outside of java.lang) is NOT permitted.
● You are allowed to define any local variables you may need to implement the methods in this
specification (inside methods). You are NOT allowed to define any additional instance or static
variables or constants beyond those specified in the write-up, except for public static helpe
methods.
● Exceptions do not NEED to have e
or messages, but a descriptive e
or message may help you
debug your code and is recommended.
● You are allowed to define additional private helper methods.
● Only your TwiteratorTester.java file may include a main method.
● All classes and methods must have their own Javadoc-style method header comments in
accordance with the CS 300 Course Style Guide.
● Any source code provided in this specification may be included ve
atim in your program
without attribution.
● Run your program locally before you submit to Gradescope. If it doesn’t work on you
computer, it will not work on Gradescope.
Need More Help?
Check out the resources available to CS 300 students here:
https:
canvas.wisc.edu/courses/344658/pages
esources
©2023 Mouna Kacem, Ho
es LeGault — University of Wisconsin–Madison
2
https:
canvas.wisc.edu/courses/344658/pages/course-style-guide
https:
canvas.wisc.edu/courses/344658/pages
esources
P07 Twitter Feed Pair Programming: NOT ALLOWED
CS 300: Programming II – Spring 2023 Due: 11:59 PM CDT on WED 04/12
CS 300 Assignment Requirements
You are responsible for following the requirements listed on both of these pages on all CS 300
assignments, whether you’ve read them recently or not. Take a moment to review them if it’s been a
while:
● Academic Conduct Expectations and Advice, which addresses such questions as:
○ How much can you talk to your classmates?
○ How much can you look up on the internet?
○ What do I do about hardware problems?
○ and more!
● Course Style Guide, which addresses such questions as:
○ What should my source code look like?
○ How much should I comment?
○ and more!
Getting Started
1. Create a new project in Eclipse, called something like P07 Twitter Feed.
a. Ensure this project uses Java 17. Select “JavaSE-17” under “Use an execution
environment JRE” in the New Java Project dialog box.
. Do not create a project-specific package; use the default package.
2. Add the TimelineMode.java enum and ListADT.java interface from the assignment page to you
project.
3. FOR NOW, create three (3) Java source files within that project’s src folder:
a. User.java (does NOT include a main method)
. Tweet.java (does NOT include a main method)
c. TwiteratorTester.java (includes a main method)
You will create more files later! But let’s start here.
1. What You’ll Store in the Data Structure
To begin this program, we need objects to store in our data structure. We will model the users of ou
fake-Twitter with the User class (where we’ll store information about, for example, their username and
whether they have an important blue checkmark) and the tweets that they make will be modeled in the
Tweet class.
The relationship between these two classes is “has-a” – every Tweet object has a User data field. So I
ecommend beginning with the User class! Both of these are very simple objects with just a few
accessors and mutators; see the javadocs: User and Tweet
©2023 Mouna Kacem, Ho
es LeGault — University of Wisconsin–Madison
3
https:
canvas.wisc.edu/courses/344658/pages/assignment-expectations-and-advice
https:
canvas.wisc.edu/courses/344658/pages/course-style-guide
https:
canvas.wisc.edu/courses/344658/pages/installing-eclipse-ide-with-java-11
https:
cs300-www.cs.wisc.edu/wp/wp-content/uploads/2020/12/sp2023/p7/javadocs/User.html
https:
cs300-www.cs.wisc.edu/wp/wp-content/uploads/2020/12/sp2023/p7/javadocs/Tweet.html
P07 Twitter Feed Pair Programming: NOT ALLOWED
CS 300: Programming II – Spring 2023 Due: 11:59 PM CDT on WED 04/12
1.1 Testing Your Objects
In your TwiteratorTester class, create two methods to verify that the User and Tweet classes are
working properly:
public static boolean testUser()
public static boolean testTweet()
Make sure to initialize the dateGenerator static field in Tweet before testing by calling the
setCalendar()method; if you care about a specific timestamp (for example, if you are testing
toString()) then see below for how to get a specific time. Otherwise, you can just use
Calendar.getInstance() for the cu
ent time.
1.2 toString() examples
Both the User and Tweet classes contain an ove
idden implementation of Object’s toString()
method. We’ll format Users so that they look like typical Twitter usernames (except with an asterisk *
instead of an important-looking blue checkmark for verified users):
Verified User with username “uwmadison” Un-verified User with username “dril”
"@uwmadison*" "@dril"
(Be sure to implement the behavior that usernames are not allowed to contain * characters! We don’t
want people faking verification, do we?)
Tweets will have this format (this is @dril’s tweet from the screenshot on the cover page):
tweet from @dril at Tue May 22 14:46:03 CDT 2012:
-- IF THE ZOO BANS ME FOR HOLLERING AT THE ANIMALS I WILL FACE GOD AND WALK
BACKWARDS INTO HELL
-- likes: 5892
-- retweets: 4523
That is: all Tweets begin with the text "tweet from" and the String representation of their User,
followed by "at" and the String representation of their timestamp. The next line (which begins "-- ")
contains the text of the tweet; the next two lines (also beginning with "-- ") display the number of
likes and retweets on the tweet. There is NO newline character at the end of this String.
✅ To get this specific timestamp, I added the following lines to my code before I created the Tweet:
Calendar test = Calendar.getInstance();
test.set(2012, Calendar.MAY, 22, 14, 46, 03);
Tweet.setCalendar(test);
©2023 Mouna Kacem, Ho
es LeGault — University of Wisconsin–Madison
4
P07 Twitter Feed Pair Programming: NOT ALLOWED
CS 300: Programming II – Spring 2023 Due: 11:59 PM CDT on WED 04/12
2. Creating Your Data Structure
1. Create two (2) more files in your project’s src folder:
a. TweetNode.java (does NOT include a main method)
. TwitterFeed.java (implements the ListADT interface; does NOT include a main method)
(That’s still not everything for this project, but we’re getting there.)
A TweetNode is a singly-linked list node containing a Tweet object. Per the javadocs, this must have
accessors and mutators for the reference to the next node in the list, but only an accessor for its Tweet
value. If you want to replace the value at a certain location in the list, you’ll have to create an entirely
new node to do so.
TwitterFeed is our singly-linked list and implements the provided ListADT interface. Note that ListADT
is a generic interface! What type should go in the
in TwitterFeed’s class header in order to make its
methods match the javadocs? (Note: you can ignore the Iterable interface for now. We’ll add it later.)
2.1 Testing Your Data Structure
In your TwiteratorTester class, create the following methods to verify that the TweetNode and
TwitterFeed classes are working properly. The following are just some suggestions to get you started
testing and do NOT include all edge cases – you’ll need to add more to verify your code works.
public static boolean testNode()
public static boolean testAddTweet()
public static boolean testInsertTweet()
public static boolean testDeleteTweet()
For testNode(), create at least two (2) TweetNodes and connect one to the other. Verify that the
accessor methods of the two nodes are working properly.
For testAddTweet(), create a TwitterFeed and verify that it is empty and has size 0. Use
addFirst()/addLast() to add a Tweet to it. Verify that it is no longer empty, has size 1,
contains() the Tweet you just added, and that get(0)matches that Tweet. Try this a few more
times, and also test getHead()/getTail().
For testInsertTweet(), create a TwitterFeed and several Tweet objects. Add them using add()
with various indexes. Verify that the size is co
ect, and that get() with various indexes returns the
Tweets you expect. You may also wish to test getHead()/getTail().
For testDeleteTweet(), create a TwitterFeed and add at least five (5) Tweet objects. Try removing
the last Tweet and verify that getTail() has been updated co
ectly; try removing the first Tweet and
verify that getHead() has been updated co
ectly. Then try removing a Tweet from a middle index (like
1) and verify that when you get() that index, it returns the value you expect.
©2023 Mouna Kacem, Ho
es LeGault — University of Wisconsin–Madison
5
https:
cs300-www.cs.wisc.edu/wp/wp-content/uploads/2020/12/sp2023/p7/javadocs/TweetNode.html
https:
cs300-www.cs.wisc.edu/wp/wp-content/uploads/2020/12/sp2023/p7/javadocs/TwitterFeed.html
P07 Twitter Feed Pair Programming: NOT ALLOWED
CS 300: Programming II – Spring 2023 Due: 11:59 PM CDT on WED 04/12
3. Iterating Through Your Data Structure
1. Create the last three (3) files in your project’s src folder:
a. ChronoTwiterator.java (javadocs)
. RatioTwiterator.java (javadocs)
c. VerifiedTwiterator.java (javadocs)
2. All of these classes MUST implement the Iterator interface (from java.util.Iterator) on Tweet
objects, and include exactly one (1) data field:
private TweetNode next;
the next linked node in the list
3.1 ChronoTwiterato
This object iterates through TweetNode objects using the links between them. To complete this class:
1. Implement a single-argument constructor that expects a TweetNode and sets up the data field
next to that provided value.
2. Ove
ide Iterator’s hasNext()method to return true if and only if there are more elements to
iterate through. NOTE: until a Tweet has actually been returned by the next()method, it is still
waiting to be iterated through!
3. Ove
ide Iterator’s next()method to return the Tweet in next’s TweetNode and advance
next to the next TweetNode in the list. This method must throw a NoSuchElementException if
there are no more values to return (make sure you import it).
Once you have the ChronoTwiterator completed, modify your TwitterFeed to ALSO implement the
Iterable
interface and add the following method to the class:
@Ove
ide
public Iterato
Tweet> iterator() {
eturn new ChronoTwiterator(this.head);
}
Add a descriptive Javadoc comment! You’ll be modifying this method slightly in the future.
3.2 Testing ChronoTwiterato
In your TwiteratorTester class, create the following methods to verify that ChronoTwiterator is
working properly (remember to initialize dateGenerator):
public static boolean testChronoTwiterator()
For this method, DO NOT test ChronoTwiterator directly! Instead, create a TwitterFeed object and
add at least three (3) Tweets to it. Then, use an enhanced-for loop (also called a for-each loop) to
iterate directly through the TwitterFeed and verify that all Tweets are returned in the co
ect order.
©2023 Mouna Kacem, Ho
es LeGault — University of Wisconsin–Madison
6
https:
cs300-www.cs.wisc.edu/wp/wp-content/uploads/2020/12/sp2023/p7/javadocs/ChronoTwiterator.html
https:
cs300-www.cs.wisc.edu/wp/wp-content/uploads/2020/12/sp2023/p7/javadocs/RatioTwiterator.html
https:
cs300-www.cs.wisc.edu/wp/wp-content/uploads/2020/12/sp2023/p7/javadocs/VerifiedTwiterator.html
P07 Twitter Feed Pair Programming: NOT ALLOWED
CS 300: Programming II – Spring 2023 Due: 11:59 PM CDT on WED 04/12
3.3 VerifiedTwiterato
This object iterates through TweetNode objects similarly to ChronoTwiterator, but skips any Tweets
made by un-verified users.
1. The single-argument constructor has the same signature as ChronoTwiterator, but rathe
than just setting next to be the provided parameter directly, it must check whether the
provided TweetNode contains a Tweet from a verified User. If it doesn’t, it should move to the
next linked TweetNode and check again, until it finds a Tweet from a verified User or runs out
of TweetNodes.
2. hasNext() and next() also work similarly to ChronoTwiterator, but remember to skip
over any Tweets from unverified Users.
3. Once VerifiedTwiterator is complete, modify TwitterFeed’s iterator()method to
eturn a ChronoTwiterator when the mode is CHRONOLOGICAL, a VerifiedTwiterato
when the mode is VERIFIED_ONLY, and null otherwise.
In your TwiteratorTester class, create the following methods to verify that VerifiedTwiterato
is working properly (remember to initialize dateGenerator):
public static boolean testVerifiedTwiterator()
and test it similarly to your ChronoTwiterator. Be sure to add at least one Tweet from a verified
User to your TwitterFeed when you test!
3.4 RatioTwiterato
This object iterates through TweetNode objects similarly to ChronoTwiterator, but skips any Tweets
with a value from getLikesRatio() that is below a given threshold.
1