code: public String getUploadHook(CmsObject cms, String uploadFolder) {
  
          if (m_postUploadHandler != null) {
              return m_postUploadHandler.getUploadHook(cms, uploadFolder);
          }
          I_CmsDialogHandler handler = getDialogHandler(CmsDialogSelector.DIALOG_PROPERTY);
          if ((handler != null) && (handler instanceof I_CmsPostUploadDialogHandler)) {
              return ((I_CmsPostUploadDialogHandler)handler).getUploadHook(cms, uploadFolder);
          } else {
              return null;
          }
      }
docs: Gets the upload hook URI which should be opened for an upload to a given folder.<p>
  This method will return null if no upload hook should be used for the given upload folder.<p>
  
  The API for this upload hook is as follows:
  
  The upload hook will be called with the following parameters:
  
  resources (required): a comma separated list of the structure ids of the uploaded resources
  if this is omitted
  closelink (optional): a link which should be opened once the upload hook has finished whatever
  it is doing
  
  @param cms the current CMS context
  @param uploadFolder the folder for which the upload hook should be found
  
  @return the URI of the upload hook or null