Singly-Linked List Solution

ou are to code a singly-linked list with a head and a tail reference. A linked list is a collection of nodes, each having a data item and a reference pointing to the next node. The next reference for the last node in this list must be null, as it is not circular. Do not use a phantom node to represent the start or end of your list. A phantom or sentinel node is a node that does not store data held by the list and is used solely to indicate the start or end of a linked list. If your list contains n elements, then it should contain exactly n nodes.




Your linked list implementation will implement the LinkedListInterface provided. It will use the default constructor (the one with no parameter) which is automatically provided by Java. Do not write your own constructor.




Nodes




The linked list consists of nodes. A class LinkedListNode is provided to you. LinkedListNode has three methods to access and set the next node, and to access the data in the node.




Adding




You will implement three add() methods. One will add to the front, one will add to the back, and one will add anywhere in the list. When adding the rst element to an empty list, the new node should be both the head and the tail. See the interface for more details.




Removing




Removing, just like adding, can be done from the front, the back, or anywhere in your linked list. In addition, the rst instance of a speci c value from the list can be removed. When removing from the front, the rst node should be removed and the head reference should be updated. When removing from the back, the last node should be removed and the tail reference should be updated. When removing




1
Homework 2: Singly-Linked List Due: See T-Square










from the middle, the previous node of the removed node should point to the next node of the removed node. Make sure that you set any pointers to the deleted nodes to null. See the interface for more details.




Checking Equality




For the removeFirstOccurrence() method, you will need to compare the elements in your list to the given data. You may be tempted to use == like with primitives, but this does not work as expected with objects. In Java, using the == operator to compare object variables only returns true when comparing the exact same objects. The objects may be functionally identical, but if they're not the exact same bytes in memory, then the operator will returns false. Therefore, you'll want to use the objects' equals() method to check if they're the same.




Grading




Here is the grading breakdown for the assignment. There are various deductions not listed that are incurred when breaking the rules listed in this PDF, and in other various circumstances.




Methods:






addAtIndex
11pts




addToFront
7pts




addToBack
7pts




removeAtIndex
8pts




removeFromFront
6pts




removeFromBack
6pts




removeFirstOccurrence
5pts




get
10pts




toArray
5pts




clear
5pts




isEmpty
5pts




Other:






Checkstyle
10pts




E ciency
15pts




Total:
100pts







Keep in mind that add functions are necessary to test other functions, so if an add doesn't work, remove tests might fail as the items to be removed were not added correctly. Additionally, the size function is used many times throughout the tests, so if the size isn't updated correctly or the method itself doesn't work, many tests can fail.




A note on JUnits




We have provided a very basic set of tests for your code, in LinkedListStudentTests.java. These tests do not guarantee the correctness of your code (by any measure), nor does it guarantee you any grade. You may additionally post your own set of tests for others to use on the Georgia Tech GitHub as a gist. Do NOT post your tests on the public GitHub. There will be a link to the Georgia Tech GitHub as well as a list of JUnits other students have posted on the class Piazza (when it comes up).




If you need help on running JUnits, there is a guide, available on T-Square under Resources, to help you run JUnits on the command line or in IntelliJ.






















2
Homework 2: Singly-Linked List Due: See T-Square










Style and Formatting




It is important that your code is not only functional but is also written clearly and with good style. We will be checking your code against a style checker that we are providing. It is located in T-Square, under Resources, along with instructions on how to use it. We will take o a point for every style error that occurs. If you feel like what you wrote is in accordance with good style but still sets o the style checker please email Raymond Ortiz (rortiz9@gatech.edu) with the subject header of \CheckStyle XML".




Javadocs




Javadoc any helper methods you create in a style similar to the existing Javadocs. If a method is overridden or implemented from a superclass or an interface, you may use @Override instead of writing Javadocs. Any Javadocs you write must be useful and describe the contract, parameters, and return value of the method; random or useless javadocs added only to appease Checkstyle will lose points.




Exceptions




When throwing exceptions, you must include a message by passing in a String as a parameter. The mes-sage must be useful and tell the user what went wrong. \Error", \BAD THING HAPPENED", and \fail" are not good messages. The name of the exception itself is not a good message.




For example:




throw new PDFReadException("Did not read PDF, will lose points.");




throw new IllegalArgumentException("Cannot insert null data into data structure.");




Generics




If available, use the generic type of the class; do not use the raw type of the class. For example, use new ArrayList<Integer() instead of new ArrayList(). Using the raw type of the class will result in a penalty.




Forbidden Statements




You may not use these in your code at any time in CS 1332.




break may only be used in switch-case statements




continue package




System.arraycopy() clone()




assert()




Arrays class Array class




Collections class




Collection.toArray()




Re ection APIs







3
Homework 2: Singly-Linked List Due: See T-Square










Inner or nested classes







Debug print statements are ne, but nothing should be printed when we run your code. We expect clean runs - printing to the console when we're grading will result in a penalty. If you submit these, we will take o points.




Provided




The following le(s) have been provided to you. There are several, but you will only edit one of them.




 
LinkedListInterface.java




This is the interface you will implement. All instructions for what the methods should do are in the javadocs. Do not alter this le.




 
SinglyLinkedList.java




This is the class in which you will implement the interface. Feel free to add private helper methods but do not add any new public methods, inner/nested classes, instance variables, or static variables.




 
LinkedListNode.java




This class represents a single node in the linked list. It encapsulates data and the next reference. Do not alter this le.




 
LinkedListStudentTests.java




This is the test class that contains a set of tests covering the basic operations on the SinglyLinkedList class. It is not intended to be exhaustive and does not guarantee any type of grade. Write your own tests to ensure you cover all edge cases.







Deliverables




You must submit all of the following le(s). Please make sure the lename matches the lename(s) below. Be sure you receive the con rmation email from T-Square, and then download your uploaded les to a new folder, copy over the interfaces, recompile, and run. It is your responsibility to re-test your submission and discover editing oddities, upload issues, etc.




 
SinglyLinkedList.java





























































4