feat: add class to read filestream

src/ReadFile.java

@@ -0,0 +1,34 @@
+import java.io.File;
+import java.io.FileNotFoundException;
+import java.util.ArrayList;
+import java.util.List;
+import java.util.Scanner;
+
+public class ReadFile {
+	/**
+	 * Opens a file and returns a list of all the lines in the file
+	 * @param filename the name of the file with, only allowing a .txt extension
+	 * @return The contents of the file
+	 */
+	public List<String> open(String filename) throws IllegalArgumentException, FileNotFoundException {
+		// Check that the filetype is correct, otherwise, throw IllegalArgumentException
+		if (!filename.endsWith(".txt")) {
+			throw new IllegalArgumentException("The filename is not a .txt format");
+		}
+		
+		// Open the file that was defined
+		File file = new File(filename);
+		Scanner reader = new Scanner(file);
+		
+		// List for all the separate lines on the database
+		List<String> data = new ArrayList<>();
+		
+		// Go through all the lines in the file and append them to the list `data`
+		while (reader.hasNextLine()) {
+			String currentData = reader.nextLine();
+			data.add(currentData);
+		}
+		
+		return data;
+	}
+}