add ability to read and write from file

src/main/java/edu/ntnu/idi/idatt2003/gruppe42/Millions.java

@@ -2,7 +2,6 @@
 
 public class Millions {
   public static void main(String[] args) {
-    System.out.println("PLEASE WORK GIT");
-    }
-}
 
+  }
+}

src/main/java/edu/ntnu/idi/idatt2003/gruppe42/Model/StockFileHandler.java

@@ -0,0 +1,77 @@
+package edu.ntnu.idi.idatt2003.gruppe42.Model;
+
+import java.io.BufferedReader;
+import java.io.BufferedWriter;
+import java.io.FileReader;
+import java.io.IOException;
+import java.math.BigDecimal;
+import java.nio.file.Files;
+import java.nio.file.Path;
+import java.util.ArrayList;
+import java.util.List;
+
+/**
+ * Utility class for handling file data.
+ * Includes methods for reading and writing from file, as well as parsing stock data into objects.
+ * Using BufferedReader/BufferedWriter for optimized handling.
+ */
+public class StockFileHandler {
+
+  /**
+   * Method for parsing stock data into stock objects.
+   *
+   * @param path the relative path of the file being parsed (from source root)
+   * @return list of stock objects parsed from data file
+   * @throws IOException if file not found
+   */
+  public static List<Stock> readFromFile(Path path) throws IOException {
+
+    List<Stock> stocks = new ArrayList<>();
+
+    try (BufferedReader bufferedReader = new BufferedReader(new FileReader(path.toFile()))) {
+      String line;
+      while ((line = bufferedReader.readLine()) != null) {
+        line = line.trim();
+
+        if (line.isEmpty() || line.startsWith("#")) {
+          continue;
+        }
+
+        String[] parts = line.split(",");
+
+        String symbol = parts[0];
+        String company = parts[1];
+        BigDecimal salePrice = new BigDecimal(parts[2].trim());
+
+        stocks.add(new Stock(symbol, company, salePrice));
+      }
+    }
+    return stocks;
+  }
+
+  /**
+   * Method for writing stock information to file.
+   *
+   * @param path the relative path of the file being parsed (from source root)
+   * @param stocks list of stock objects to be transcribed to data file
+   * @throws IOException if file not found
+   */
+  public static void writeToFile(Path path, List<Stock> stocks) throws IOException {
+
+    try (BufferedWriter writer = Files.newBufferedWriter(path)) {
+      writer.write("# S&P 500 Companies by Market Cap");
+      writer.write("\n# Ticker,Name,Price");
+      writer.newLine();
+
+      for (Stock stock : stocks) {
+        String line = String.format("%s,%s,%s",
+                stock.getSymbol(),
+                stock.getCompany(),
+                stock.getSalesPrice());
+
+        writer.write(line);
+        writer.newLine();
+      }
+    }
+  }
+}