Assignment 1: Java finger exercises ► Assignment 1: Java finger exercises 1 Purpose 2 Getting started 3 Adding a class 4 Adding a method 5 Grading standards 6 Submission Assignment 1: Java finger exercises 1 Purpose 2 Getting started 3 Adding a class 4 Adding a method 5 Grading standards 5.1 The style guide 6 Submission 6.1 Deliverables 6.2 Instructions 6.8 Assignment 1: Java finger exercises Due:Fri 05/12 at 8:59pm; self-evaluation due Sat 05/13 at 8:59pm Starter files: code.zip 1 Purpose The primary goal of this assignment is to get you writing Java (again or for the first time). As a secondary goal, completing this assignment will help you ensure that you have a properly configured and working Java development environment and IDE, and that you can use the submission system (to be described elsewhere). 2 Getting started Before you start this assignment, you should make sure that you’ve set up a proper CS 3500 environment. You can view the accompanying video tutorial for more help. We are using the Java SE Development Kit 8 toolchain (JDK 8). You need a good Java IDE. We recommend IntelliJ IDEA, ; (instructions for licensing it are available ; on Piazza), but you may use whatever IDE you like. You will need to install Git if you don’t already have it. Once you’ve installed JDK 8, Git, and an IDE, you probably need to tell the IDE where to find the JDK and Git. Additionally, you should configure your IDE to set your Java language level to 8—this is a separate configuration step. We will be taking full advantage of Java 8 in this course. Finally, you also need to configure your IDE with the appropriate style settings: see The style guide below. Go to https://github.ccs.neu.edu/ and make sure you can login with your CCIS username and password. (If you don’t have a CCIS username and password, you must get one.) If you have trouble with this step, you should skip to the second method in the next step (for now). Get the code for this homework assignment using the “Starter files” link above. Take a look at the provided code: The code from Lecture 2 appears in src/cs3500/hw01/publication, with tests in test/cs3500/hw01/publication. File test/Hw01TypeChecks.java contains a small class designed to help you detect when your code may not compile against the grading tests. In particular, if your project cannot compile while Hw01TypeChecks.java—unmodified!—is a part of it, then it won’t compile for the course staff either. 3 Adding a class This part of the assignment is a continuation of the code written in Lecture 2: The essence of objects. In particular, you will write a Java class Webpage (in package cs3500.hw01.publication) that implements the Publication interface from lecture, with the same functionality as web page objects created by the ISL+λ function new-webpage, as seen in the lecture notes. Write a class Webpage that implements the Publication interface. It must define a public constructor: public Webpage(String title, String url, String retrieved) The signature of the constructor, including the order of the arguments, is important to enable automated-test–based grading for functional correctness. Don’t forget to write a good Javadoc comment. See how to cite a webpage in MLA and APA style by looking at the Racket code in Lecture 2. Write a JUnit 4 test class, WebpageTest, that tests both public methods of Webpage. 4 Adding a method Compared to the version from class this week, there are two changes in the code for this homework: Interface Duration now has an additional method, format(String), along with a Javadoc comment detailing its specification. Class AbstractDurationFormatTest contains two simple test methods for format, called formatExample1 and formatExample2. These serve as examples, and you will need to add several more to have good test coverage. Add tests for format only to this class, or else the autograder will not work properly. To complete this assignment: You must write sufficient tests to be confident that your implementation of the format method is correct. Your tests should exercise every non-trivially distinct possibility. It is recommended that you write these tests before attempting to implement the format method as specified below. Doing so will help you clarify how the method is supposed to work. The autograder for this portion of the homework is slightly tricky, and requires your code to be designed in a particular way. First, your tests must be placed in the AbstractDurationFormatTest class, and you must leave unchanged the portion of the file marked "Leave this section alone". Second, do not explicitly use new in your tests: as we did in class, use the hms and sec methods to construct examples of Durations. The autograder will run your tests against several new Duration classes with deliberately-buggy format implementations, and against one perfectly-correct implementation; to earn full credit on this autograder, you must have sufficient tests to catch all of these bugs. In other words, you will succeed on this homework if you write enough correct tests to comprehensively check the format method, such that at least one fails on any buggy implementation of it, but all tests pass on the correct implementation. Remember: test failures are good things! You must implement the Duration.format(String) method in the appropriate place(s). Your implementation must not use any of the string replacement methods such as replace or replaceAll. (We strongly suggest that you use iteration and not recursion to process a string.) The Javadoc description of this method is a sufficient specification for this method, but requires careful attention: an overly-hasty reading will probably miss some edge cases. The autograder will also test your implementation for correctness, regardless of whether you wrote your own test cases. 5 Grading standards For this assignment, you will be graded on whether your code compiles, whether your code implements the specification (functional correctness), whether you thoroughly test every method that you write, and how well you follow the style guide. 5.1 The style guide Coding style is important. For this class we follow Google’s Java style guide. It’s comprehesive but not very long, so I suggest reading the whole thing and then referring to it as needed. While it can’t yet take on full responsibility for formatting code—much less for programming style more broadly—your IDE may be able to help you follow the code formatting portion of the style guide: For Intellij IDEA, download intellij-java-google-style.xml and save it in the config/codestyles/ subdirectory of your IntelliJ configuration folder. Then from within IntelliJ, go to File > Other Settings > Default Settings..., then in the dialog that pops up, go to Editor / Code Style, and select it in the Scheme dropdown, where it should have appeared as an option. If you’ve already created a project, then you’ll additionally need to set this as the project style, using File > Settings. For Eclipse, download the eclipse-java-google-style.xml. Under Window > Preferences, select Java / Code Style / Formatter and import the settings. Check here for more info. 6 Submission 6.1 Deliverables Your submission should include Webpage.java, WebpageTest.java, and any files you had to modify or create in order to implement and test your format(String) method. Please ensure that your submission is a zip file. This zip file should contain your src/ and test/ folders from your project. Please do not put these folders within another folder before submitting, as the grader will not find your files. These folders should mimic the folder structure required for your packages (e.g. for a class inside cs3500.hw01.duration, the src/ folder should contain a cs3500 folder, inside which is a hw01 inside which is a duration folder. Do ensure that your code compiles. Half of your grade is for correctness as determined by automated testing, so code that doesn’t compile is subject to a 50% penalty up front. 6.2 Instructions You will submit your homework at https://handins.ccs.neu.edu. Log in with your CCS username and password. If you do not have one, you cannot submit your homework, so obtain one immediately and email the course staff. Once logged in, you will need to enter some simple profile information (name and nickname, mostly), and upload a picture of yourself so we recognize you. After completing that profile, you’ll be taken to a page like this one: In this screen: The navigation bar at the top will take you to this homepage via the Bottlenose icon, to your profile via your nickname, and to a list of your currently enrolled courses. You can also log out. Arranged by semester, you can see your current courses, and your homeworks and teams within them. In the homework area, you have links to all currently available homeworks, along with basic information about them. The score bubbles to the right show each of your submissions for that assignment; the green one is the one being graded. Clicking on a homework link will take you to a page where you can see all your submissions in more detail, as well as create a new submission. Note that for assignments with autograders, it may take a little while for the grade to appear; in the meantime it will appear as “Missing”. Do not panic!
