code: public void checkOfflineProject(CmsDbContext dbc) throws CmsVfsException {
  
          if (dbc.currentProject().isOnlineProject()) {
              throw new CmsVfsException(
                  org.opencms.file.Messages.get().container(
                      org.opencms.file.Messages.ERR_NOT_ALLOWED_IN_ONLINE_PROJECT_0));
          }
      }
docs: Checks if the project in the given database context is not the "Online" project,
  and throws an Exception if this is the case.<p>
  
  This is used to ensure a user is in an "Offline" project
  before write access to VFS resources is granted.<p>
  
  @param dbc the current OpenCms users database context
  
  @throws CmsVfsException if the project in the given database context is the "Online" project