File IO Lab

Learning Goals

• Practice reading and writing a text file.

Instructions

Create a program to write and read in a grocery list.

To implement the reading and writing of a text file, consider the following instructions and tips:

• Modify the GroceryListDriver class.
  • Write the method to write to a text file.
    • Use a FileWriter object to write out a grocery list.
    • Each item in the list should be on its own new line.
    • Refer back to the File Input Output lesson.
  • Write the method to read a text file line-by-line.
    • Use a Scanner object to read from the text file.
    • Return a String to print out to the console the list of groceries.
    • Refer back to the File Input Output Lesson.
• When running the GroceryListDriver class, pass in a file named grocery-list.txt.
• Remove the @Disabled annotation from the unit tests and ensure that the tests pass successfully. Refactor as needed.

Starter Code

Consider the GroceryListDriver class that has some starter code in it for you to use:

import java.util.ArrayList;
import java.util.Arrays;
import java.util.List;
import java.util.Scanner;

public class GroceryListDriver {
    public static void main(String[] args) {
        List<String> groceryList = new ArrayList<String>(Arrays.asList(
                "Apples",
                "Bananas",
                "Cookies"
        ));
        Scanner scanner = new Scanner(System.in);
        System.out.println("What file are we working with today?");
        String filepath = scanner.nextLine();

        writeFile(filepath, groceryList);
        System.out.println(readFile(filepath));
    }

    public static String readFile(String filepath) {
        // Write your code here!
    }

    public static void writeFile(String filepath, List<String> groceryList) {
        // Write your code here!
    }
}

Once you have implemented the readFile() and writeFile() methods, you should have the following output printed to the console:

Apples
Bananas
Cookies

Unit Tests

Consider the following unit tests to help you implement the writeFile() and readFile() methods:

import org.junit.jupiter.api.AfterEach;
import org.junit.jupiter.api.BeforeEach;
import org.junit.jupiter.api.Disabled;
import org.junit.jupiter.api.Test;

import java.util.ArrayList;
import java.util.List;

import static org.junit.jupiter.api.Assertions.*;

class GroceryListDriverTest {

    List<String> groceryList;

    @BeforeEach
    void setUp() {
        groceryList = new ArrayList<String>();
    }

    @AfterEach
    void tearDown() {
    }

    @Disabled
    @Test
    void testOneItem() {
        String filepath = "grocery-test1.txt";
        groceryList.add("Bananas");
        GroceryListDriver.writeFile(filepath, groceryList);
        assertEquals("Bananas\n", GroceryListDriver.readFile(filepath));
    }

    @Disabled
    @Test
    void testMultipleItems() {
        String filepath = "grocery-test2.txt";
        groceryList.add("Chips");
        groceryList.add("Salsa");
        groceryList.add("Peanut Butter");
        groceryList.add("Jelly");
        String expected = String.format("%s%n%s%n%s%n%s%n", "Chips", "Salsa", "Peanut Butter", "Jelly");
        GroceryListDriver.writeFile(filepath, groceryList);
        assertEquals(expected, GroceryListDriver.readFile(filepath));
    }

    @Disabled
    @Test
    void testNoItems() {
        String filepath = "grocery-test3.txt";
        GroceryListDriver.writeFile(filepath, groceryList);
        assertEquals("", GroceryListDriver.readFile(filepath));
    }
}