public void add(DeletionRule rule) {
   if (findByCommonName(rule.getCommonName()) != null)
     throw new IllegalStateException(
         "DeletionRule with cn: '" + rule.getCommonName() + "' already exists");
   if (findByStorageSystemGroupID(rule.getStorageSystemGroupID()) != null)
     throw new IllegalStateException(
         "DeletionRule with Storage System Group ID: '"
             + rule.getStorageSystemGroupID()
             + "' already exists");
   list.add(rule);
 }
 public DeletionRule findByCommonName(String commonName) {
   for (DeletionRule rule : list) if (commonName.equals(rule.getCommonName())) return rule;
   return null;
 }