Learning Objectives
After completing this project you should be able to: use ArrayLists to maintain and process collections of objects use for-each loops use while loops read data from external text files use static methods available in the Java library
Step 1: Create a New BlueJ Project
Step 2: Download Files Download the CustomerNames.txt file and save it in the folder that BlueJ created for this new project. There are 10,000 entries! You will not see it from within BlueJ but you can see it from within the Windows Explorer. Download the provided GUI.java and save it in the project folder. You should see this class within BlueJ. Do not make any changes to it until later.
Step 3: Create a class called Customer (5 pts) Implement a class to maintain information about a customer including: gender (boolean), first name, last name, birth date (day, month, year), address, city, ST, zip code, credit card brand and current balance (double). Provide appropriate names and data types for each of the instance variables. public Customer (String info) a constructor that initializes all of the instance variables to appropriate values. See information below about parsing Strings into smaller pieces. female, Amy, Zu, 4/9/1960, 54 Elm St, Any City, NC, 27834, Visa, 15339.19 public boolean isFemale() return true if female and false if male. provide get methods for each of the instance variables (except gender). public String getFirst() public String getLast() public String getAddress() public String getCity() public String getState() public int getZip() public String getCreditCard() public int getDay() public int getMonth() public int getYear() public double getBalance() provide matching set methods for each instance variable. Although the set methods are not used for this project it is good practice to provide them for most classes. public String toString( ) return a formatted mailing label (a single String with embedded newlines using
) . For example, John Smith 123 Elm St. Anytown, ST 12345 public static void main(String args[]) thoroughly test each of the methods in this class.
Step 4: Create a class called CustomerDatabase (65 pts) Unless otherwise specified use the elegant for-each loop to search the ArrayList. Define an instance variable that holds an ArrayList of Customer. You should only need ONE instance variable. public CustomerDatabase ( ) a constructor that instantiates an empty ArrayList in one line of code. No customers are inserted yet. public void readCustomerData(String filename) open the provided filename and read all the data. There are 10,000 entries in CustomerNames.txt. Refer to the information about reading text files later in this document. public void addCustomer (Customer c) add the customer to the ArrayList. This method contains one line of code. public int countCustomers ( ) return the number of names in the database. This method only needs to contain one line of code! public int countCustomers (int zip) this overloaded method has an identical name as the previous method but returns the number of customers with zip as a zipcode. public int countDebtFree ( ) return the number of cardholders with no debt. public Customer getHighestDebt ( ) return the person with the highest credit card balance. public Customer getYoungestCardholder ( ) return the youngest person in the database.
Give careful thought to this one! If you find more than one customer with the same age, return just ONE. public String getCardSummary(String card) return a String that summarizes the total number of cards and average debt for the requested card type. Valid entries are: Discover, Visa and MasterCard. Return an appropriate error message if the card is not valid. If there are no customers with the specific card, return a message indicating that Customers were not found. Use the NumberFormat class to help format the dollars and cents output. Sample result should look like the following. Discover: 1981 cards with average balance of $3,735.20 public ArrayList Customer Text File This file contains fictional customer information. A sample line of the data file is shown below.
Note that items are separated by commas and the birthday is separated by slashes. The readCustomerData(String filename) method reads one line at a time and passes the text to the Customer class constructor. female, Amy, Zu, 4/9/1960, 54 Elm St, AnyCity, NC, 27834, Visa, 15339.19 Sample Method to Read a Text File The following method reads from a text data file one line at a time and prints to the screen. You will have to modify this code to create Customers and insert into the database. Sample Code public void readCustomerData(String filename){ // Attempt to read the complete set of data from file. try{ File f = new File(filename); Scanner sc = new Scanner(f); String logline; // read header information first logline = sc.nextLine(); while(sc.hasNext()) { logline = sc.nextLine(); // remove this print statement after method works System.out.println(logline); // add two lines of code to instantiate a new Customer // and add to database } sc.close(); } catch(IOException e) { System.out.println(Failed to read the data file: + filename); } }
Step 5: Software Testing (5 pts) Software developers must plan from the beginning that their solution is correct. BlueJ allows you to instantiate objects and invoke individual methods. You can carefully check each method and compare actual results with expected results.
However, this gets tedious. Another approach is to write a main method that calls all the other methods. Create 4-8 Customers and add them to the database. Your tests will be more thorough than the following incomplete example. public static void main(String args[]){ String info = male, Joe, Smith, 4/20/1963, addr, San Francisco, CA, 49401, Discover, 12345.67; Customer cust1 = new Customer(info); info = female, Jo Anne, Henderson, 2/19/1972, addr2, Detroit, MI, 49401, Mastercard, 12000; Customer cust2 = new Customer(info); CustomerDatabase db = new CustomerDatabase(); db.addCustomer(cust1); db.addCustomer(cust2); System.out.println(db.getYoungestCardholder()); System.out.println(db.getHighestDebt()); } JUnit Testing As an alternative, JUnit is a Java library that helps to automate software testing. A JUnit test file DatabaseTest.java has been provided on BlackBoard.
Refer to Project 2 instructions for additional information about JUnit Testing. Remember, your class names and method names must match exactly with these specifications. A compile error for DatabaseTest.java suggests a mismatch of some identifier Sample ResultsResults from the GUI with the text file properly read should yield the following results. Result from countCustomers Total Customers: 10000 Customers that are Debt Free: 2137 Result from getHighestDebt Jessica Anderson 1957 Patterson Street Houston, TX 77063 Result of a search for delf 0 customers found Result of a search for allen First fourteen names omitted John Sadowski 2741 Dark Hollow Road Allentown, NJ 8501 Jennie Lee 429 Jerome Avenue Mcallen, TX 78501 16 names listed
Step 6: Create a GUI class (15 pts) Now that you have the basic application working within its own class it is time to create a more interesting graphical user interface for the user. See examples, posted on BlackBoard, of BorderLayout and BoxLayout. Modify the provided GUI class. Define instance variables for a CustomerDatabase object, and JButtons as needed to match the sample screenshot. The central JTextArea is provided for you. GUI Constructor Instantiate a CustomerDatabase and invoke the readCustomerData() method. db = new CustomerDatabase(); db.readCustomerData(CustomerNames.txt); Several menu items are created for you.
The JTextArea is created for you and inserted in the CENTER region. The JPanel for the three TextFields with corresponding labels has been created for you and inserted in the SOUTH region. Create the following private method: Private void setupButtons () Create a JPanel for the four JButtons. This panel must use Box Layout to display buttons in a column. JPanel eastPanel = new JPanel(); eastPanel.setLayout(new BoxLayout(eastPanel, BoxLayout.Y_AXIS)); Instantiate the buttons Add the buttons to the eastPanel Register the buttons with the ActionListener. An example: youngestButton.addActionListener(this); Add the eastPanel to the EAST theGUI.add(BorderLayout.EAST, eastPanel); ActionPerformed method The actionPerformed method has been created for you. You will add several if statements for each of the buttons and menu items. if (e.getSource() == quitItem){ System.exit(1); } if(e.getSource() == youngest){ results.setText(); c = db.getYoungestCardholder(); results.append(c.toString()); } Additional Methods Add the following methods to the GUI class. public void displayCustomers (ArrayList
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