code: public <D> RuleContext<D> read(final DataProvider<D>... dataProviders) {
          final List<DataProvider<D>> registeredDataProviders = new ArrayList<DataProvider<D>>();
          if (dataProviders != null) {
              Collections.addAll(registeredDataProviders, dataProviders);
          }
          return new RuleContext<D>(registeredTriggers, registeredDataProviders);
      }
docs: Adds the first data providers to the validator.
  
  @param dataProviders Data providers to be added.
  @param <D>           Type of data to be validated.<br>It can be, for instance,
  the type of data handled by a component, or the
  type of the component itself.
  
  @return Rule context allowing to add data providers and rules, but not triggers.