code: public String setPropertyTypeFromStringValue(
  			PropertyIdValue propertyIdValue, StringValue value) {
  		String datatype = getPropertyType(propertyIdValue);
  		if (datatype == null) {
  			logger.warn("Could not fetch datatype of "
  					+ propertyIdValue.getIri() + ". Assuming type "
  					+ DatatypeIdValue.DT_STRING);
  			return DatatypeIdValue.DT_STRING; // default type for StringValue
  		} else {
  			return datatype;
  		}
  	}
docs: Returns the IRI of the primitive Type of an Property for
  {@link StringValue} objects.
  
  @param propertyIdValue
  @param value