Homework 2: Contact List

Due September 16 @ 8:00pm on Autolab

In this assignment you’ll build a simple contact list, using data in names.txt as an initial dataset. We’re not writing the next Microsoft Outlook here, but we’ll get a basic contact list up and running.

Download a pre-prepared Eclipse Project hw2.zip and import it into Eclipse using these instructions. You will make all of your changes inside of Contact.java and Contacts.java.

Your Tasks

You will need to write the following items:

• Contact Class
  You need to fill-in the Contact class with everything required to store and manage a single contact. You will need relevant instance variables, at least one constructor, and methods (including a toString). The design of the object is up to you.
• Contacts(String filename) (Constructor in Contacts.java)
  This constructor takes a filename (a String), opens the file, and assuming it is openable, loads the contacts array with data from the file. While doing this, it needs to ensure that the contact list does not contain any entries with duplicate andrew IDs. If the file contains two or more entries with the same andrew ID, only the first one should be added to the contact list.
• void removeContact(String id)
  Removes the entry for the contact with andrew ID, id, from the contact list, if it exists. If there is no contact with the andrew ID then this method should do nothing. When removing the contact, other contacts in the array will need to be shifted to ensure there are no “gaps” in the array.
• boolean addContact(String firstName, String lastName, String andrewId, String phone, String group1, String group2)
  Add a contact to the Contact list. If there is room in the contacts array, verify that the new Contact has a unique andrew ID and, if so, add the contact after the current last element, updating numContacts appropriately, and return true. Otherwise, return false.
• void changePhone(String id, String newNumber)
  If a contact with andrew ID, id, exists, change the phone number that belongs to the contact with that ID to newNumber.
• String[] allInGroup(String g)
  Returns an array containing all the andrew IDs for contacts in the contact list that are in the specified group, g. The array should be exact size of the number of andrew IDs it contains.
• void updateDatabase(String filename)
  Creates a file with name provided by fileName and writes the contents of the contact list to this file. The file should follow the same file format as the input file. Your file must be written so that it can be read back in by your program.
  Note: When testing this, you will quickly discover that Eclipse doesn’t automatically show you new files that appear in a project. To force Eclipse to update the list of files in a project, right-click on the project and choose “Refresh”.

File Format

The input (and output) files that your program should be able to work with have a comma separated value (CSV) format. Each line the file contains the information for one contact, with each field of that contact separated by a comma. The fields are:

First Name, Last Name, andrew ID, Phone #, Group 1, Group 2

Most of these fields are self explanatory. Group 1 and Group 2 represent contact groups which this contact belongs to.

The provided Eclipse project includes a sample file (names.txt) that you can use for testing. (Looking at it will also help you make sure you understand the file format.)

Grading and Submission

There are multiple parts of the grading of this assignment:

1. For the first 90 points, your submission will be auto-graded on Autolab.
2. For the next 5 points, your submission will be manually graded to check for good implementation methodologies. (Did you use a good approach to solving the problems?)
3. For the next 5 points, your submission will be manually graded to check for good testcases that you include in the main method. (Do you have 2-3 basic testcases for each method, and do they all execute automatically?)
4. Your code will also be checked for style. The parts of style that can be checked automatically (things like spacing, indentation, the use of CamelCase, etc.) are automatically checked by the autograder. Other parts of style, such as choosing good variable names, will be checked manually. Autograded style guide violations can result in, at most, -10 points. Manually checked style guide violations can result in, at most, -5 points.

You will submit your program to Autolab. Login to the system and you will see homework 2. Once there, you need to submit a zip file containing your code. Luck for you, however, Eclipse can create this zip file for you. Check out these instructions for exporting. On Autolab, you’ll submit that exported zip file. On the page that follows your submission you will see your live score (out of 90). It may take up to a few minutes for your score to appear; during that time just hit refresh in your browser. If you receive a lower score than you expect, you can click on the score to see the feedback from the autograder.

For this assignment you have 12 submissions.

Important Notes

• It may be helpful for you to write a helper function in the Contacts class. Something like findContact(String id) that returns the integer index in the array of the contact with the provided andrew ID (or -1 if the ID isn’t found). This helper function could be useful in many other functions…
• If you have questions, please post to Piazza. The course staff, including the instructor, monitor and answer questions there.
• When posting to Piazza, if you include any code make sure your question is posted privately to the instructors, and not to the entire class.
• Do not change the names of any of the provided methods or files.
• After you submit to Autolab, make sure you check your score. If you aren’t sure how to do this, then ask.
• There is no partial credit on Autolab testcases. Your Autolab score is your Autolab score.
• Read the last bullet point again. Seriously, we won’t go back later and increase your Autolab score for any reason. Even if you worked really hard and it was only a minor error…
• You can submit to Autolab multiple times. So, after you submit you should check your score. If it isn’t a 90 you can keep working until it is.
• Don’t forget to write your own testcases in the main method of the Contacts class. We’ll be taking a look at those!