Exercise 1: Reading a Data File (Level 3)

In this exercise, you will create a class that reads customer and account data from a flat file.

Task 1 - Copying Resource Files

1. Create the data/ directory.
   mkdir data
   
   
2. Copy the teat.dat file from the resources/madO9_textapps/ directory into the data/ directory.
   cp ~/resources/mod09_textapps/test.dat data/
   
   

Task 2 - Creating the Datasource Class

Creste the src/com/mybank/data/ directory.

mkdir src/com/mybank/data

Using a text editor, create the DataSource class source file in the src/com/mybank/data/ directory. This class must satisfy the UML diagram in Figure 9-1 on page Lab 9-2.

1. Declare the Datasource class in the com.mybank.data package.
   

            package com.mybank.data;
            // insert import statements here
            public class DataSource { 
              // insert code here
            }

2. Add the dataFile attribute to the DataSource class.
   private File dataFile;
3. Add a public constructor that takes a string argument dataFilePath and initializes the dataFile attribute.

   public DataSource (String dataFilePath) {

   this.dataFile = new File(dataFi1ePath);

   }

4. Add a public method, loadData, that populates the eank customer objects and each customer's account objects, shown as follows:

   public void loadData() throws IOExceptim {
      // Data source variables
      Scanner input = new Scanner(dataFi1e);
      // Domain variables
      Customer customer;
      int numOfCustomers = input.nextInt();
      for ( int idx = 0; idx < numOfCustomers; idx++ ) {
         // Create customer object
         String firstName = input.next();
         String lastName = input.next();
         Bank.addCustomer(firstName, lastName);
         customer = Bank.getCustomer(idx);
         // Create customer accounts
         int numOfAccounts = input.nextInt();
         while ( numOfAccounts --> 0 ) {
            // Create a specific type of account
            char accountType = input.next().charAt(0);
            switch ( accountType ) {
               // Savings account
               case 'S': {
                  float initBalance = input.nextFloat();
                  float interestRate = input.nextFloat();
                  customer.addAccount (new SavingsAccount (initBalance,
                                                       interestRate));
                  break;
               }
               // Checking account
               case 'C' : {
                  float initBalance = input.nextFloat();
                  float overdraftProtection = input.nextFloat();
                  customer.addAccount(new CheckingAccount(initBalance,
                                                          overdraftProtection));
                  break;
               }
            } // END of switch
         ) // END of create accounts loop
      } //END of create customers loop
   
   }

Task 3 - Copying the TestReport Program

cd ~/resources/mod09_textapps/TestReport.java
      src/com/mybank/test/

Task 4 - Compiling the TestReport Program

Task 5 - Running the TestReport Program

On the command line, use the java command to run the test program.

java -cp ../classes com.mybank.test.TestReport
../data/test.dat