code: @Override
      public Collection<Object> getKeys(String scope) throws InvalidScopeException, InternalCacheEngineException {
          try {
              return cacheStoreAdapter.getKeys(scope);
          } catch (InvalidScopeException ex) {
              throw ex;
          } catch (Exception ex) {
              throw new InternalCacheEngineException("Exception while getting keys of items within scope " + scope, ex);
          }
      }
docs: {@inheritDoc}