code: public void splitRegexField(String sourceField, String targetField, String regexString, String index) {
          TransformationStep step = new TransformationStep();
          step.setTargetField(targetField);
          step.setSourceFields(sourceField);
          step.setOperationParameter(TransformationConstants.REGEX_PARAM, regexString);
          step.setOperationParameter(TransformationConstants.INDEX_PARAM, index);
          step.setOperationName("splitRegex");
          steps.add(step);
      }
docs: Adds a split regex transformation step to the transformation description. The value of the source field is split
  based on the split string as regular expression into parts. Based on the given index, the result will be set to
  the target field. The index needs to be an integer value. All fields need to be of the type String.