private void initParams(SolrParams params) {
    String prependFields = params.get(PREPEND_FIELDS);
    for (String field : prependFields.split(",")) {
      String trimmed = field.trim();
      if (this.indexSchema.getFieldOrNull(trimmed) != null) {
        this.prependFields.add(trimmed);
      } else {
        log.error("Unsupported format for" + PREPEND_FIELDS + ":" + trimmed
            + ". Skipping prepending langs to this field.");
      }
    }

    String prependGranularity = params.get(PREPEND_GRANULARITY);
    if (prependGranularity != null && prependGranularity.trim().length() > 0) {
      if (prependGranularity.trim().equals("document")) {
        this.prependGranularity = PrependGranularities.document;
      } else if (prependGranularity.trim().equals("field")) {
        this.prependGranularity = PrependGranularities.field;
      } else if (prependGranularity.trim().equals("fieldValue")) {
        this.prependGranularity = PrependGranularities.fieldValue;
      } else {
        log.error("Unsupported format for" + PREPEND_GRANULARITY + ":"
            + prependGranularity + ". Using "
            + this.prependGranularity.toString() + ".");
      }
    }

    this.hidePrependedLangs = params.getBool(HIDE_PREPENDED_LANGS, false);

  }