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Homework 1: Array List
Homework 1: Array List
1. All submitted code must compile under JDK 8. This includes unused code, so don’t submit extra files that don’t compile. Any compile errors will result in a 0. 2. Do not include any package declarations in your classes. 3. Do not change any existing class headers, constructors, or method signatures. 4. Do not add additional public methods. 5. Do not use anything that would trivialize the assignment. (e.g. don’t import/use java.util.ArrayList for a Array List assignment. Ask if you are unsure.) 6. Always be very conscious of efficiency. Even if your method is to be O(n), traversing the structure multiple times is considered inefficient unless that is absolutely required (and that case is extremely rare). 7. You must submit your source code, the .java files, not the compiled .class files. 8. After you submit your files, redownload them and run them to make sure they are what you intended to submit. You are responsible if you submit the wrong files. Array List You are to code an Array List. An Array List is a list data structure backed by an array. Your array list implementation will implement the ArrayListInterface provided. A constructor stub is provided. You must add any necessary statements to this constructor. Do not change the constructor provided or implement a different one. 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. See the interface for more details. Removing Removing, just like adding, can be done from the front, the back, or anywhere in your ArrayList. When removing from the front or from the middle of the list, the element should be removed and all subsequent elements should be shifted forward by one position. When removing from the back, the last element should be set to null in the array. All unused positions in the backing array must be set to null. See the interface for more details. Capacity The starting capacity of your ArrayList should be the constant INITIAL CAPACITY defined in ArrayListInterface. Reference the constant as-is. Do not simply copy the value of the constant. If, while adding an element, the ArrayList does not have enough space, you should regrow the backing array to twice its old capacity. Do not regrow the backing array when removing elements. 1 Homework 1: Array List Due: See T-Square Grading Here is the grading breakdown for the assignment: Methods: addAtIndex 11pts addToFront 7pts addToBack 7pts removeAtIndex 8pts removeFromFront 6pts removeFromBack 4pts get 10pts clear 5pts isEmpty 5pts Regrowing 12pts Other: Checkstyle 10pts Efficiency 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 ArrayListStudentTests.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. 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 off a point for every style error that occurs. If you feel like what you wrote is in accordance with good style but still sets off 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. 2 Homework 1: Array List Due: See T-Square Exceptions When throwing exceptions, you must include a message by passing in a String as a parameter. The message 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() 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() • Reflection APIs • Inner or nested classes Debug print statements are fine, 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 off points. Provided The following file(s) have been provided to you. There are several, but you will only edit one of them. 1. ArrayListInterface.java This is the interface you will implement. All instructions for what the methods should do are in the javadocs. Do not alter this file. 3 Homework 1: Array List Due: See T-Square 2. ArrayList.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. 3. ArrayListStudentTests.java This is the test class that contains a set of tests covering the basic operations on the ArrayList 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 file(s). Please make sure the filename matches the filename(s) below. Be sure you receive the confirmation email from T-Square, and then download your uploaded files 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. 1. ArrayList.java 4
1. All submitted code must compile under JDK 8. This includes unused code, so don’t submit extra files that don’t compile. Any compile errors will result in a 0. 2. Do not include any package declarations in your classes. 3. Do not change any existing class headers, constructors, or method signatures. 4. Do not add additional public methods. 5. Do not use anything that would trivialize the assignment. (e.g. don’t import/use java.util.ArrayList for a Array List assignment. Ask if you are unsure.) 6. Always be very conscious of efficiency. Even if your method is to be O(n), traversing the structure multiple times is considered inefficient unless that is absolutely required (and that case is extremely rare). 7. You must submit your source code, the .java files, not the compiled .class files. 8. After you submit your files, redownload them and run them to make sure they are what you intended to submit. You are responsible if you submit the wrong files. Array List You are to code an Array List. An Array List is a list data structure backed by an array. Your array list implementation will implement the ArrayListInterface provided. A constructor stub is provided. You must add any necessary statements to this constructor. Do not change the constructor provided or implement a different one. 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. See the interface for more details. Removing Removing, just like adding, can be done from the front, the back, or anywhere in your ArrayList. When removing from the front or from the middle of the list, the element should be removed and all subsequent elements should be shifted forward by one position. When removing from the back, the last element should be set to null in the array. All unused positions in the backing array must be set to null. See the interface for more details. Capacity The starting capacity of your ArrayList should be the constant INITIAL CAPACITY defined in ArrayListInterface. Reference the constant as-is. Do not simply copy the value of the constant. If, while adding an element, the ArrayList does not have enough space, you should regrow the backing array to twice its old capacity. Do not regrow the backing array when removing elements. 1 Homework 1: Array List Due: See T-Square Grading Here is the grading breakdown for the assignment: Methods: addAtIndex 11pts addToFront 7pts addToBack 7pts removeAtIndex 8pts removeFromFront 6pts removeFromBack 4pts get 10pts clear 5pts isEmpty 5pts Regrowing 12pts Other: Checkstyle 10pts Efficiency 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 ArrayListStudentTests.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. 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 off a point for every style error that occurs. If you feel like what you wrote is in accordance with good style but still sets off 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. 2 Homework 1: Array List Due: See T-Square Exceptions When throwing exceptions, you must include a message by passing in a String as a parameter. The message 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() 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() • Reflection APIs • Inner or nested classes Debug print statements are fine, 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 off points. Provided The following file(s) have been provided to you. There are several, but you will only edit one of them. 1. ArrayListInterface.java This is the interface you will implement. All instructions for what the methods should do are in the javadocs. Do not alter this file. 3 Homework 1: Array List Due: See T-Square 2. ArrayList.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. 3. ArrayListStudentTests.java This is the test class that contains a set of tests covering the basic operations on the ArrayList 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 file(s). Please make sure the filename matches the filename(s) below. Be sure you receive the confirmation email from T-Square, and then download your uploaded files 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. 1. ArrayList.java 4
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