code: public void setDataProviderOutputTransformers(Transformer... dataProviderOutputTransformers) {
          if (dataProviderOutputTransformers == null) {
              this.dataProviderOutputTransformers = null;
          } else {
              this.dataProviderOutputTransformers = new ArrayList<Transformer>();
              Collections.addAll(this.dataProviderOutputTransformers, dataProviderOutputTransformers);
          }
      }
docs: Sets teh transformers transforming the output of each data provider before they are mapped to the rules.
  
  @param dataProviderOutputTransformers Data provider output transformers.