Added file and device verification

FilePathAdd.java

@@ -1,3 +1,6 @@
+import java.io.IOException;
+import java.nio.file.Files;
+import java.nio.file.Path;
 import java.util.Scanner;
 
 public class FilePathAdd {
@@ -5,9 +8,25 @@ public class FilePathAdd {
     public static String ImagePath = "";
 
     protected static String filePath(Scanner UserInput) {
-        System.out.println("Please enter the FULL Path of your ISO / Image. ()");
+        fileQuestion();
-        ImagePath = UserInput.nextLine();
+        while (true) {
-        System.out.println("Using File: " + ImagePath);
+            ImagePath = UserInput.nextLine();
-        return ImagePath;
+            if (ImagePath.isBlank()) {
+                System.out.println("Oops.. You didn't specify a file, did you missclick?");
+                continue;
+            }
+            Path path = Path.of(ImagePath);
+            try {
+                Files.readAttributes(path, "basic:size");
+                System.out.println("Using File: " + ImagePath);
+                return ImagePath;
+            } catch (IOException e) {
+                System.out.println("Failed to access file, invalid path or no access to file! Please try again.");
+            }
+        }
+    }
+
+    protected static void fileQuestion() {
+        System.out.println("Please enter the FULL Path of your ISO / Image. (No tab-complete)");
     }
 }

Flasher.java

@@ -5,7 +5,7 @@ public class Flasher {
         
         String input = "";
         
-        System.out.println("The programm wil use the following configuration, do you want to flash with this? (y/n)");
+        System.out.println("The programm wil use the following configuration, do you want to flash with this? (Y/n)");
         System.out.println("    - To be flashed device: " + StorageDeviceLister.fullPath);
         System.out.println("    - To be used path: " + FilePathAdd.ImagePath);
         System.out.println("    - To bed used blocksize: " + BlockSize.blockSizeString);

Main.java

@@ -13,7 +13,7 @@ public class Main {
             System.out.println("Canceling...");
             System.exit(0);
         }
-        StorageDeviceLister.deviceList(UserInput);
+        StorageDeviceLister.deviceCheck(UserInput);
         FilePathAdd.filePath(UserInput);
         BlockSize.blockSize(UserInput);
         OflagHandler.handleOflag(UserInput);

StorageDeviceLister.java

@@ -1,6 +1,7 @@
 import java.io.BufferedReader;
 import java.io.IOException;
 import java.io.InputStreamReader;
+import java.nio.file.Path;
 import java.util.Scanner;
 
 public class StorageDeviceLister {
@@ -8,26 +9,48 @@ public class StorageDeviceLister {
     public static String device = "";
     public static String fullPath = "";
 
-    protected static String deviceList(Scanner UserInput) {
+    protected static String deviceCheck(Scanner UserInput) {
+        // 1. lsblk wird genau EINMAL aufgerufen
+        deviceList();
 
+        // 2. Die Abfrage-Schleife
+        while (true) {
+            device = UserInput.nextLine();
+            if (device.isBlank()) {
+                System.out.println("Oops... Device name is empty. Did you missclick?");
+                continue;
+            }
+            Path path = Path.of("/dev/" + device);
+
+            try {
+                // Versuche, den echten Pfad zu finden
+                fullPath = path.toRealPath().toString();
+                
+                // Wenn wir hier ankommen, war der Pfad gültig
+                System.out.println("Using device: " + fullPath);
+                return fullPath; 
+
+            } catch (IOException e) {
+                // Fehler-Output, danach springt die Schleife wieder nach oben
+                System.out.println("Failed to access device! Invalid path or no access. Please try again.");
+            }
+        }
+    }
+
+    private static void deviceList() {
         try {
             ProcessBuilder pb = new ProcessBuilder("lsblk");
             Process process = pb.start();
-            
+            BufferedReader reader = new BufferedReader(new InputStreamReader(process.getInputStream()));
-            BufferedReader reader = new BufferedReader(
-                new InputStreamReader(process.getInputStream())
-            );
-            
             String line;
             while ((line = reader.readLine()) != null) {
                 System.out.println(line);
             }
-        } catch (IOException e) {
+            process.waitFor();
+            System.out.println("Please enter the name of your device (without /dev/):");
+
+        } catch (IOException | InterruptedException e) {
             e.printStackTrace();
         }
-        String device = UserInput.nextLine();
-        System.out.println("Using device: " + "/dev/" + device);
-        fullPath = "/dev/" + device;
-        return fullPath;
     }
 }