private Iterator<?>[] createIterators(Object[] dataProviders, List<DataProviderInfo> dataProviderInfos) {
      if (context.getErrorInfoCollector().hasErrors()) {
        return null;
      }
      Assert.that(dataProviders.length == dataProviderInfos.size());

      Iterator<?>[] iterators = new Iterator<?>[dataProviders.length];
      for (int i = 0; i < dataProviders.length; i++) {
        Iterator<?> iter = createIterator(dataProviders[i], dataProviderInfos.get(i));
        if (iter == null) {
          return null;
        }
        iterators[i] = iter;
      }

      return iterators;
    }
Returns how many data providers are processed by this data provider multiplier.

@return how many data providers are processed by this data provider multiplier
spock-core/src/main/java/org/spockframework/runtime/DataIteratorFactory.java