code: @Override
      public String buildRESTParentHierarchy(String pid)
              throws MelcoeXacmlException {
          Set<String> parents = getParents(pid);
          if (parents == null || parents.size() == 0) {
              return "/" + pid;
          }
  
          String[] parentArray = parents.toArray(new String[parents.size()]);
  
          return buildRESTParentHierarchy(parentArray[0]) + "/" + pid;
      }
docs: /*
  (non-Javadoc)
  @see
  org.fcrepo.server.security.xacml.pdp.finder.support.RelationshipResolver#buildRESTParentHierarchy
  (java.lang.String)