// assumes that the global "session" belongs to an Administrator
 protected void setPermissionToAnonymous(String perm) {
   DocumentModel doc = session.getRootDocument();
   ACP acp = doc.getACP();
   if (acp == null) {
     acp = new ACPImpl();
   }
   UserEntryImpl userEntry = new UserEntryImpl("anonymous");
   userEntry.addPrivilege(perm);
   acp.setRules("test", new UserEntry[] {userEntry});
   doc.setACP(acp, true);
   session.save();
 }
 protected void setPermissionToEveryone(String... perms) {
   DocumentModel doc = session.getRootDocument();
   ACP acp = doc.getACP();
   if (acp == null) {
     acp = new ACPImpl();
   }
   UserEntryImpl userEntry = new UserEntryImpl(EVERYONE);
   for (String perm : perms) {
     userEntry.addPrivilege(perm);
   }
   acp.setRules("test", new UserEntry[] {userEntry});
   doc.setACP(acp, true);
   session.save();
 }