Update PIResponse.java

Author: lukasmatusiewicz

src/main/java/org/privacyidea/PIResponse.java

@@ -170,10 +170,31 @@ public String mergedSignRequest()
             return "";
         }
     }
+    
+    /**
+     * Get all U2F challenges from the multi_challenge.
+     *
+     * @return List of U2F objects or empty list
+     */
+    public List<U2F> u2fSignRequests()
+    {
+        List<U2F> ret = new ArrayList<>();
+        multichallenge.stream()
+                      .filter(c -> TOKEN_TYPE_U2F.equals(c.getType()))
+                      .collect(Collectors.toList())
+                      .forEach(c ->
+                               {
+                                   if (c instanceof U2F)
+                                   {
+                                       ret.add((U2F) c);
+                                   }
+                               });
+        return ret;
+    }
 
     @Override
     public String toString()
     {
         return rawMessage;
     }
-}
+}