check admin privileges

G-Earth/src/main/java/gearth/Main.java

@@ -1,10 +1,14 @@
 package gearth;
 
+import gearth.misc.AdminValidator;
 import javafx.application.Application;
 import javafx.application.Platform;
 import javafx.fxml.FXMLLoader;
 import javafx.scene.Parent;
 import javafx.scene.Scene;
+import javafx.scene.control.Alert;
+import javafx.scene.control.ButtonType;
+import javafx.scene.layout.Region;
 import javafx.stage.Stage;
 import gearth.ui.GEarthController;
 
@@ -35,6 +39,11 @@ public class Main extends Application {
             System.exit(0);
         });
 
+        if (!AdminValidator.isAdmin()) {
+            Alert alert = new Alert(Alert.AlertType.ERROR, "G-Earth needs admin privileges in order to work properly, please restart G-Earth unless you know what you're doing", ButtonType.OK);
+            alert.getDialogPane().setMinHeight(Region.USE_PREF_SIZE);
+            alert.show();
+        }
     }
 
     public static String[] args;

G-Earth/src/main/java/gearth/misc/AdminValidator.java

@@ -0,0 +1,37 @@
+package gearth.misc;
+
+import java.io.PrintStream;
+import java.util.prefs.Preferences;
+
+/**
+ * Created by Jeunez on 5/11/2018.
+ */
+public class AdminValidator {
+
+    //https://stackoverflow.com/questions/4350356/detect-if-java-application-was-run-as-a-windows-admin
+
+    private static Boolean isAdmin = null;
+
+    public static boolean isAdmin() {
+        if (isAdmin == null) {
+            Preferences prefs = Preferences.systemRoot();
+            PrintStream systemErr = System.err;
+            synchronized(systemErr){    // better synchroize to avoid problems with other threads that access System.err
+                System.setErr(null);
+                try{
+                    prefs.put("foo", "bar"); // SecurityException on Windows
+                    prefs.remove("foo");
+                    prefs.flush(); // BackingStoreException on Linux
+                    isAdmin = true;
+                }catch(Exception e){
+                    isAdmin = false;
+                }finally{
+                    System.setErr(systemErr);
+                }
+            }
+        }
+
+        return isAdmin;
+    }
+
+}