code: public CmsFolder readFolder(String resourcename, CmsResourceFilter filter) throws CmsException {
  
          return m_securityManager.readFolder(m_context, addSiteRoot(resourcename), filter);
      }
docs: Reads a folder resource from the VFS,
  using the specified resource filter.<p>
  
  The specified filter controls what kind of resources should be "found"
  during the read operation. This will depend on the application. For example,
  using <code>{@link CmsResourceFilter#DEFAULT}</code> will only return currently
  "valid" resources, while using <code>{@link CmsResourceFilter#IGNORE_EXPIRATION}</code>
  will ignore the date release / date expired information of the resource.<p>
  
  @param resourcename the name of the folder resource to read (full current site relative path)
  @param filter the resource filter to use while reading
  
  @return the folder resource that was read
  
  @throws CmsException if the resource could not be read for any reason
  
  @see #readResource(String, CmsResourceFilter)