fixed issue where users in usergroups were not loaded correctly

java/com.sap.sse.security.common/src/com/sap/sse/security/shared/dto/UserGroupDTO.java

@@ -1,6 +1,7 @@
 package com.sap.sse.security.shared.dto;
 
 import java.util.HashSet;
+import java.util.Set;
 import java.util.UUID;
 
 import com.sap.sse.security.shared.AbstractUserGroupImpl;
@@ -16,7 +17,7 @@ public class UserGroupDTO extends AbstractUserGroupImpl<StrippedUserDTO> impleme
         super(null, null, null);
     }
 
-    public UserGroupDTO(HashSet<StrippedUserDTO> users, UUID id, String name) {
+    public UserGroupDTO(Set<StrippedUserDTO> users, UUID id, String name) {
         super(users, id, name);
     }
 

java/com.sap.sse.security.ui/src/main/java/com/sap/sse/security/ui/server/SecurityDTOFactory.java

@@ -3,6 +3,7 @@ package com.sap.sse.security.ui.server;
 import java.util.ArrayList;
 import java.util.Collection;
 import java.util.HashMap;
+import java.util.HashSet;
 import java.util.List;
 import java.util.Map;
 import java.util.Map.Entry;
@@ -184,14 +185,7 @@ public class SecurityDTOFactory {
         if (userGroup == null) {
             result = null;
         } else {
-            // we do not cache this, as they are only valid as root type of objects, so they cannot be already be in the
-            // map at this point
-            if (fromOriginalToStrippedDownUserGroup.get(userGroup) != null) {
-                throw new IllegalArgumentException(
-                        "A stripped mapping does already exist for this usergroup, this should never be the case");
-            }
-            // FIXME can this generic cast be made better?
-            result = new UserGroupDTO(userGroup.getId(), userGroup.getName());
+            result = new UserGroupDTO(createStrippedUsersFromUsers(userGroup.getUsers(), securityService, fromOriginalToStrippedDownUser, fromOriginalToStrippedDownUserGroup),userGroup.getId(), userGroup.getName());
             SecurityDTOUtil.addSecurityInformation(this, securityService, result, userGroup.getIdentifier(),
                     fromOriginalToStrippedDownUser, fromOriginalToStrippedDownUserGroup);
         }
@@ -313,6 +307,15 @@ public class SecurityDTOFactory {
                 annotation.getDisplayNameOfAnnotatedObject());
     }
 
+    public Set<StrippedUserDTO> createStrippedUsersFromUsers(Iterable<User> users, SecurityService securityService,
+            Map<User, StrippedUserDTO> fromOriginalToStrippedDownUser,
+            Map<UserGroup, StrippedUserGroupDTO> fromOriginalToStrippedDownUserGroup) {
+        Set<StrippedUserDTO> result = new HashSet<>();
+        users.forEach(user -> result.add(createStrippedUserFromUser(user, securityService,
+                fromOriginalToStrippedDownUser, fromOriginalToStrippedDownUserGroup)));
+        return result;
+    }
+
     public StrippedUserDTO createStrippedUserFromUser(User user, SecurityService securityService,
             Map<User, StrippedUserDTO> fromOriginalToStrippedDownUser,
             Map<UserGroup, StrippedUserGroupDTO> fromOriginalToStrippedDownUserGroup) {