code: public List<CmsResource> getSubFolders(String resourcename, CmsResourceFilter filter) throws CmsException {
  
          CmsResource resource = readResource(resourcename, CmsResourceFilter.ALL);
          return m_securityManager.readChildResources(m_context, resource, filter, true, false);
      }
docs: Returns all folder resources contained in a folder.<p>
  
  With the <code>{@link CmsResourceFilter}</code> provided as parameter
  you can control if you want to include deleted, invisible or
  time-invalid resources in the result.<p>
  
  @param resourcename the full current site relative path of the resource to return the child resources for.
  
  @return a list of all child folder <code>{@link CmsResource}</code>s
  @param filter the resource filter to use
  
  @throws CmsException if something goes wrong