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CS1331 Homework 08 – LinkedList Solution
Authors: Brittney, Ariel, Ian, Vince, Tejas
Problem Description
Welcome to your final challenge, er- I mean, final homework! For this homework, you will be writing a concrete implementation of a List ADT--a Singly-Linked List. LinkedLists are comprised of Nodes, which are objects that store data and have a pointer to the next Node in the list, which has its own data and next Node, and so on.
Solution Description
We have provided List.java (different than the List interface from java.util package), an abstract data type (ADT) that contains abstract methods for all of the functionality your LinkedList needs to implement. Using your knowledge of Collections, Generics, and Iterable, you will write a Node class that represents a singular element in a LinkedList and a LinkedList class that represents a Singly-LinkedList and implements all of the functionality defined in the provided List<T> interface. As always, you will need to adhere to proper Checkstyle including Javadocs.
Node.java
Your LinkedList will consist of Nodes. Each Node will contain its own data and point to the next Node in the list. This class takes in a generic type parameter for the type of data the Node will hold, so be sure to reflect that in your class declaration, instance data, and methods. Make sure that this is a separate file from your LinkedList class.
• Variables
o data
This represents the data stored in the Node
Should be of generic type o Node next
This represents the Node that comes next in the list
This Node’s data type will be of the same generic type as data
• Constructors o A constructor that takes values in the following order: data and next and assigns them to the corresponding instance variables.
o A constructor that takes in a data value and sets next to null.
• Methods
o Getters and setters for all instance variables.
LinkedList.java
This file contains your implementation of a Singly-LinkedList. This class takes in a generic type parameter for the type of data each Node in the LinkedList will hold, so be sure to reflect that in your class declaration, instance data, and methods. Your Singly-LinkedList should store Nodes and implement the provided List<T> interface
• Variables
o Node head
Represents the head of your LinkedList
If the LinkedList is empty, should be null
o int size
Represents the number of Nodes in your LinkedList
Remember to update size accordingly as you add to and remove from the
LinkedList
• Constructors o A no-argument constructor that initializes head to null and size to 0
• Methods
o Override all methods in the provided List<T> interface
For all methods that take in parameters you should throw the following Exceptions if the parameters are invalid:
Throw an IllegalArgumentException if any parameters are null
Throw an IndexOutOfBoundsException if an index parameter is invalid
Make sure to read the JavaDocs in the List<T> interface so you know what functionality to implement.
o To implement the iterator() method you should write an inner class named
LinkedListIterator and return an instance of it. The LinkedListIterator class should contain the following.
This class should not be generic, but should utilize the generic type from LinkedList as needed.
This class should implement Iterator<T> and override all non-default abstract methods in the Iterator<T> interface
Make sure to throw a NoSuchElementException from the abstract method stated in the Iterator<T> API to throw one when an error occurs
This class should have one instance variable named nextNode of type Node to keep track of the next element in the LinkedList.
This class should have one no-argument constructor that initializes nextNode to head.
o Getters for the instance variables.
Clarifications and Example Output
Allowed Imports
• java.util.Iterator
• java.util.NoSuchElementException
Feature Restrictions
There are a few features and methods in Java that overly simplify the concepts we are trying to teach or break our auto grader. For that reason, do not use any of the following in your final submission:
• var (the reserved keyword)
• System.exit
Checkstyle and Javadocs
You must run Checkstyle on your submission. The Checkstyle cap for this assignment is 15 points. If you don't have Checkstyle yet, download it from Canvas -> Modules -> Checkstyle Resources (all sections). Place it in the same folder as the files you want Checkstyled. Run checkstyle on your code like so:
$ java -jar checkstyle-8.28.jar yourFileName.java Starting audit...
Audit done.
The message above means there were no Checkstyle errors. If you had any errors, they would show up above this message, and the number at the end would be the points we would take off (limited by the Checkstyle cap mentioned above). The Java source files we provide contain no Checkstyle errors. In future homeworks we will be increasing this cap, so get into the habit of fixing these style errors early!
Additionally, you must Javadoc your code.
Run the following to only check your Javadocs:
$ java -jar checkstyle-8.28.jar -j yourFileName.java
Run the following to check both Javadocs and Checkstyle:
$ java -jar checkstyle-8.28.jar -a yourFileName.java
For additional help with Checkstyle see the CS 1331 Style Guide.
Collaboration
No collaboration is allowed on this assignment. See syllabus for more details.
Turn-In Procedure
Submission
To submit, upload the files listed below to the corresponding assignment on Gradescope:
• Node.java
• LinkedList.java
Please only submit the individual files—do not put them into a package or you will risk getting a zero on the assignment. Make sure you see the message stating "HW08 submitted successfully". From this point, Gradescope will run a basic autograder on your submission as discussed in the next section.
Gradescope Autograder
For each submission, you will be able to see the results of a few basic test cases on your code. Each test typically corresponds to a rubric item, and the score returned represents the performance of your code on those rubric items only. If you fail a test, you can look at the output to determine what went wrong and resubmit once you have fixed the issue.
The Gradescope tests serve two main purposes:
• Prevent upload mistakes (e.g. non-compiling code)
• Provide basic formatting and usage validation
In other words, the test cases on Gradescope are by no means comprehensive. Be sure to thoroughly test your code by considering edge cases and writing your own test files. You also should avoid using Gradescope to compile, run, or Checkstyle your code; you can do that locally on your machine.
Important Notes (Don't Skip)
• Non-compiling files will receive a 0 for all associated rubric items
• Do not submit .class files
• Test your code in addition to the basic checks on Gradescope
• Run Checkstyle on your code to avoid losing points
• Submit every file each time you resubmit
• Read the "Allowed Imports" and "Feature Restrictions" to avoid losing points
• Check on Piazza for a note containing all official clarifications
Problem Description
Welcome to your final challenge, er- I mean, final homework! For this homework, you will be writing a concrete implementation of a List ADT--a Singly-Linked List. LinkedLists are comprised of Nodes, which are objects that store data and have a pointer to the next Node in the list, which has its own data and next Node, and so on.
Solution Description
We have provided List.java (different than the List interface from java.util package), an abstract data type (ADT) that contains abstract methods for all of the functionality your LinkedList needs to implement. Using your knowledge of Collections, Generics, and Iterable, you will write a Node class that represents a singular element in a LinkedList and a LinkedList class that represents a Singly-LinkedList and implements all of the functionality defined in the provided List<T> interface. As always, you will need to adhere to proper Checkstyle including Javadocs.
Node.java
Your LinkedList will consist of Nodes. Each Node will contain its own data and point to the next Node in the list. This class takes in a generic type parameter for the type of data the Node will hold, so be sure to reflect that in your class declaration, instance data, and methods. Make sure that this is a separate file from your LinkedList class.
• Variables
o data
This represents the data stored in the Node
Should be of generic type o Node next
This represents the Node that comes next in the list
This Node’s data type will be of the same generic type as data
• Constructors o A constructor that takes values in the following order: data and next and assigns them to the corresponding instance variables.
o A constructor that takes in a data value and sets next to null.
• Methods
o Getters and setters for all instance variables.
LinkedList.java
This file contains your implementation of a Singly-LinkedList. This class takes in a generic type parameter for the type of data each Node in the LinkedList will hold, so be sure to reflect that in your class declaration, instance data, and methods. Your Singly-LinkedList should store Nodes and implement the provided List<T> interface
• Variables
o Node head
Represents the head of your LinkedList
If the LinkedList is empty, should be null
o int size
Represents the number of Nodes in your LinkedList
Remember to update size accordingly as you add to and remove from the
LinkedList
• Constructors o A no-argument constructor that initializes head to null and size to 0
• Methods
o Override all methods in the provided List<T> interface
For all methods that take in parameters you should throw the following Exceptions if the parameters are invalid:
Throw an IllegalArgumentException if any parameters are null
Throw an IndexOutOfBoundsException if an index parameter is invalid
Make sure to read the JavaDocs in the List<T> interface so you know what functionality to implement.
o To implement the iterator() method you should write an inner class named
LinkedListIterator and return an instance of it. The LinkedListIterator class should contain the following.
This class should not be generic, but should utilize the generic type from LinkedList as needed.
This class should implement Iterator<T> and override all non-default abstract methods in the Iterator<T> interface
Make sure to throw a NoSuchElementException from the abstract method stated in the Iterator<T> API to throw one when an error occurs
This class should have one instance variable named nextNode of type Node to keep track of the next element in the LinkedList.
This class should have one no-argument constructor that initializes nextNode to head.
o Getters for the instance variables.
Clarifications and Example Output
Allowed Imports
• java.util.Iterator
• java.util.NoSuchElementException
Feature Restrictions
There are a few features and methods in Java that overly simplify the concepts we are trying to teach or break our auto grader. For that reason, do not use any of the following in your final submission:
• var (the reserved keyword)
• System.exit
Checkstyle and Javadocs
You must run Checkstyle on your submission. The Checkstyle cap for this assignment is 15 points. If you don't have Checkstyle yet, download it from Canvas -> Modules -> Checkstyle Resources (all sections). Place it in the same folder as the files you want Checkstyled. Run checkstyle on your code like so:
$ java -jar checkstyle-8.28.jar yourFileName.java Starting audit...
Audit done.
The message above means there were no Checkstyle errors. If you had any errors, they would show up above this message, and the number at the end would be the points we would take off (limited by the Checkstyle cap mentioned above). The Java source files we provide contain no Checkstyle errors. In future homeworks we will be increasing this cap, so get into the habit of fixing these style errors early!
Additionally, you must Javadoc your code.
Run the following to only check your Javadocs:
$ java -jar checkstyle-8.28.jar -j yourFileName.java
Run the following to check both Javadocs and Checkstyle:
$ java -jar checkstyle-8.28.jar -a yourFileName.java
For additional help with Checkstyle see the CS 1331 Style Guide.
Collaboration
No collaboration is allowed on this assignment. See syllabus for more details.
Turn-In Procedure
Submission
To submit, upload the files listed below to the corresponding assignment on Gradescope:
• Node.java
• LinkedList.java
Please only submit the individual files—do not put them into a package or you will risk getting a zero on the assignment. Make sure you see the message stating "HW08 submitted successfully". From this point, Gradescope will run a basic autograder on your submission as discussed in the next section.
Gradescope Autograder
For each submission, you will be able to see the results of a few basic test cases on your code. Each test typically corresponds to a rubric item, and the score returned represents the performance of your code on those rubric items only. If you fail a test, you can look at the output to determine what went wrong and resubmit once you have fixed the issue.
The Gradescope tests serve two main purposes:
• Prevent upload mistakes (e.g. non-compiling code)
• Provide basic formatting and usage validation
In other words, the test cases on Gradescope are by no means comprehensive. Be sure to thoroughly test your code by considering edge cases and writing your own test files. You also should avoid using Gradescope to compile, run, or Checkstyle your code; you can do that locally on your machine.
Important Notes (Don't Skip)
• Non-compiling files will receive a 0 for all associated rubric items
• Do not submit .class files
• Test your code in addition to the basic checks on Gradescope
• Run Checkstyle on your code to avoid losing points
• Submit every file each time you resubmit
• Read the "Allowed Imports" and "Feature Restrictions" to avoid losing points
• Check on Piazza for a note containing all official clarifications
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