Description

Lab 02 CarInsuranceApp

In this lab, you will:

• Work with and complete a ‘starter’ car insurance application.
• See examples of file-based data persistence
• Work with example code that uses java classes to read and clean data. These simple introductory examples, however, speak to important skills in the context of modern programming.
• Complete the partial implementation of the application, by extending java objects and working with another controller class in the context of data reading and writing vis a vis the general notion of programming basic persistence of object states.
•
… which will result in the following outcomes:

• Appreciation of simple, structured data and how it can be read and cleaned from a java program using native java objects.
• Appreciation of how different data types can be created by parsing various data String formats.
• Knowledge of how to storage formatted data using different approaches based on object readers and streams.

Table of Contents
1.1 Preliminary 3
1.2 Exercise 1 3
1.3 Exercise 2 5
1.4 Exercise 3 6
1.5 Exercise 4 7

Figure 1: CarInsuranceStarter ………………………………………………………………………………………. 3
Figure 2: Project files and folders in windows explorer …………………………………………………… 3

1.1 Preliminary

• Download the lab 2 zip <Lab2_CarInsuranceAppStarter.zip> file from GCULearn.

• unzip and open the Lab2_CarInsuranceAppStarter project in NetBeans:

Figure 1: CarInsuranceAppStarter

• Browse, using windows explorer, if you are using windows (equivalent like Finder on MacOS) to the project folder

• Note the presence of the text files. These will be used to implement a strategy of object persistence, which is a key general theme of this lab.

• You can also view the files and folder structure in the Files view within Netbeans.

Figure 2: Project files and folders in windows explorer

1.2 Exercise 1
a. Open the Policy class, in the model folder, and note the attributes: policyId, policyType, policyOwner, carReg, carDescription and
policyStartDate. Constructor, getter and setter methods are defined as well as the overridden method toString().
Note, dates are specified as Calendar objects and a private method getFormattedStartDate()is used to produce a specified string format for output:
private String getFormattedStartDate()
{
SimpleDateFormat formatter =
new SimpleDateFormat(“yyyy-MM-dd”); String dateString =
formatter.format(this.policyStartDate.getTime()); return dateString;
}

This is then used in the toString() method:
@Override
public String toString() {
return ” Id: ” + Integer.toString(this.policyId) +
” Owner: ” + this.policyOwner +
” Reg: ” + this.carReg +
” Description: ” + this.carDescription +
” Start: ” + getFormattedStartDate() + ” “; }

b. Now open the policywithoutdrivers.txt file and note the format:
private void loadPolicyFromTextFile(String fileName) { char DELIMITER=’,’; try (BufferedReader br =
new BufferedReader(new FileReader(fileName))) {

String[] temp;
String line = br.readLine();
temp=line.split(Character.toString(DELIMITER)); int policyID = Integer.parseInt(temp[0]);
String policyType = stripQuotes(temp[1]);
String policyOwner = stripQuotes(temp[2]);
String carReg = stripQuotes(temp[3]);
String carDescription = stripQuotes(temp[4]);

A stream is opened to the text file and the readLine() method used to read a line from the text file into a String variable called line. This string is then split up an array of Strings – temp – using the split() method. Each element of the array holds a piece of text which has been delimited using, in this case, a comma – CSV file. Each element is accessed in turn, and, where necessary, converted into a variable of an appropriate type, e.g. int, Calendar etc. which are then used to create a Policy object.
A private method stripQuotes() is used to strip quotes from the start and end of Strings.
DateFormat dateFormat = new SimpleDateFormat(“yyyy-MM-dd”);
policyStartDate = dateFormat.parse(policyStartDateStr); policyStart = Calendar.getInstance(); policyStart.setTime(policyStartDate);
…
policy = new Policy(policyID, policyType, policyOwner, carReg, carDescription, policyStart);

1.3 Exercise 2
We are now going to add a list of named drivers to the policy.
a. Open the Policy class and uncomment code which refers to the attribute namedDrivers. Extend the toString() method to display named drivers.

b. Open the policywithdrivers.txt file and note the format including named drivers:

“Tony”,”Banks”,”1950-03-27”
“Phil”,”Collins”,”1951-01-30”
“Mike”,”Rutherford”,”1950:10:02”

The additional value at the end of the first line specifies the number of named drivers i.e. the number of following lines which represent named driver information.

c. Open the PolicyController class and extend the private method loadPolicyFromTextFile() as follows:

noDrivers = Integer.parseInt(temp[6]);
ArrayList<Driver> namedDrivers = new ArrayList<>(); Driver newDriver;
for (int i=0; i<noDrivers; i++) { line = br.readLine();
temp=line.split(Character.toString(DELIMITER));
String firstName = stripQuotes(temp[0]);
String surname = stripQuotes(temp[1]); dateFormat = new SimpleDateFormat(“yyyy-MM-dd”);
String dateOfBirthStr = stripQuotes(temp[2]);
dateOfBirthDate = dateFormat.parse(dateOfBirthStr); dateOfBirth = Calendar.getInstance(); dateOfBirth.setTime(dateOfBirthDate);
} catch (ParseException ex) {
Logger.getLogger(

PolicyController.class.getName()).log(Level.SEVERE, null, ex);
}

newDriver = new Driver(firstName, surname, dateOfBirth);
namedDrivers.add(newDriver);
}
The code will be located between the try-catch for policyStartDate and the creation of the policy object – note you will need to replace the call to this constructor with one that includes the namedDrivers as an argument.
d. Uncomment the addDriver() and deleteDriver() methods.

e. Run the CarInsuranceApp class and test that the policy can be successfully loaded and drivers can be added and removed.

1.4 Exercise 3
a. Open the PolicyController class and add the private method storePolicyToTextFile() as below:

private void storePolicyToTextFile(String fileName) { char DELIMITER=’,’;
try (PrintWriter output = new PrintWriter(fileName))
{
output.println(policy.toString(DELIMITER)); output.close();
} catch (FileNotFoundException ex) {
Logger.getLogger(

PolicyController.class.getName()).log(Level.SEVERE, null, ex);
}
}

Add a call to it when the Finish option is chosen from the menu:

case ‘F’:
InputHelper inputHelper = new InputHelper(); char c = inputHelper.readCharacter(
“Store to a Text File (T) or Object File (O)?”);
String fileName =
inputHelper.readString(“Enter File name”); if (c == ‘T’) {
storePolicyToTextFile(fileName);
}
else if (c == ‘O’) {
// storePolicyToObjectFile(fileName);
}
finished = true;

b. Run the CarInsuranceApp class and test that the policy can be successfully stored and re-loaded.
1.5 Exercise 4
We are now going to extend the app to include persistence using object streams.
a. Open the PolicyController class and uncomment the loadPolicyFromObjectFile() method.

b. Uncomment the storePolicyToObjectFile() method.

c. Run the CarInsuranceApp class and test that a new policy can be created and stored as an object file and then successfully loaded and displayed.

Note: You should ensure that you understand the role of each class and the operation of each method.