public void writeDirectoryMappings(final Element element) {
   if (myProject.isDefault()) {
     element.setAttribute(ATTRIBUTE_DEFAULT_PROJECT, Boolean.TRUE.toString());
   }
   for (VcsDirectoryMapping mapping : getDirectoryMappings()) {
     Element child = new Element(ELEMENT_MAPPING);
     child.setAttribute(ATTRIBUTE_DIRECTORY, mapping.getDirectory());
     child.setAttribute(ATTRIBUTE_VCS, mapping.getVcs());
     final VcsRootSettings rootSettings = mapping.getRootSettings();
     if (rootSettings != null) {
       Element rootSettingsElement = new Element(ELEMENT_ROOT_SETTINGS);
       rootSettingsElement.setAttribute(ATTRIBUTE_CLASS, rootSettings.getClass().getName());
       try {
         rootSettings.writeExternal(rootSettingsElement);
         child.addContent(rootSettingsElement);
       } catch (WriteExternalException e) {
         // don't add element
       }
     }
     element.addContent(child);
   }
 }