New improvements

overtime.txt

@@ -0,0 +1 @@
+0:09

src/main/java/rvc/timecalc/Main.java

@@ -1,6 +1,8 @@
 package rvc.timecalc;
 
 import javax.swing.JOptionPane;
+import java.io.File;
+import java.io.IOException;
 
 /**
  * @author Robert
@@ -8,9 +10,13 @@ import javax.swing.JOptionPane;
  */
 public class Main {
 
-    public static void main(String[] args) {
+    public static void main(String[] args) throws IOException {
         while (true) {
             boolean test = false;
+            File starttimeTxt = new File("starttime.txt");
+            File overtimeTxt = new File("overtime.txt");
+            String lastStartTime = Utils.readTextFromFile(starttimeTxt);
+            String lastOvertime = Utils.readTextFromFile(overtimeTxt);
             String startTime =
                     test ? "7:00" : (String) JOptionPane.showInputDialog(
                             null,
@@ -19,7 +25,7 @@ public class Main {
                             JOptionPane.PLAIN_MESSAGE,
                             null,
                             null,
-                            "7:00"
+                            lastStartTime == null ? "7:00" : lastStartTime
                     );
             String overTime =
                     test ? "0:00" : (String) JOptionPane.showInputDialog(
@@ -29,8 +35,15 @@ public class Main {
                             JOptionPane.PLAIN_MESSAGE,
                             null,
                             null,
-                            "0:00"
+                            lastOvertime == null ? "0:00" : lastOvertime
                     );
+            
+            if(!starttimeTxt.exists()) {
+                Utils.writeTextToFile(starttimeTxt, startTime);
+            }
+            if(!overtimeTxt.exists()) {
+                Utils.writeTextToFile(overtimeTxt, overTime);
+            }
             try {
                 TimeCalcWindow timeCalc =
                         new TimeCalcWindow(startTime, overTime);

src/main/java/rvc/timecalc/Utils.java

@@ -0,0 +1,54 @@
+package rvc.timecalc;
+
+import java.io.File;
+import java.io.FileInputStream;
+import java.io.FileOutputStream;
+import java.io.IOException;
+import java.nio.charset.StandardCharsets;
+import java.nio.file.Files;
+
+/**
+ * @author Robert
+ * @since 15.02.2024
+ */
+public class Utils {
+    private Utils() {
+        //Not meant to be instantiated.
+    }
+
+    /**
+     * Count of bytes per one kilobyte.
+     */
+    private static final int COUNT_OF_BYTES_PER_ONE_KILOBYTE = 1024;
+
+    /**
+     * Writes text to a file.
+     * @param file file
+     * @param text text
+     */
+    public static void writeTextToFile(final File file, final String text) {
+        FileOutputStream outputStream;
+        try {
+            outputStream = new FileOutputStream(file.getAbsolutePath());
+            byte[] strToBytes = text.getBytes();
+            outputStream.write(strToBytes);
+
+            outputStream.close();
+        } catch (IOException e) {
+            System.err.println(e);
+            throw new RuntimeException(e);
+        }
+
+    }
+
+    /**
+     * Reads text from file.
+     * @param file file
+     * @return String
+     * @throws IOException thrown, if an error during reading happens
+     */
+    public static String readTextFromFile(final File file)
+            throws IOException {
+        return new String(Files.readAllBytes(file.toPath()));
+    }
+}

starttime.txt

@@ -0,0 +1 @@
+6:39