private Value buildValue(Element fieldEl) throws Exception {
    String valueExpr = DocumentHelper.getAttribute(fieldEl, "value", true);

    Value value;

    boolean extractContent = DocumentHelper.getBooleanAttribute(fieldEl, "extractContent", false);

    String formatter = DocumentHelper.getAttribute(fieldEl, "formatter", false);
    if (formatter != null && !conf.getFormatters().hasFormatter(formatter)) {
      throw new IndexerConfException(
          "Formatter does not exist: "
              + formatter
              + " at "
              + LocationAttributes.getLocationString(fieldEl));
    }

    //
    // An index field can basically map to two kinds of values:
    //   * plain field values
    //   * dereference expressions (following links to some other record and then taking a field
    // value from it)
    //

    // A dereference expression is specified as "somelink=>somelink=>somefield"

    if (valueExpr.contains("=>")) {
      //
      // A dereference field
      //
      value = buildDerefValue(fieldEl, valueExpr, extractContent, formatter);
    } else {
      //
      // A plain field
      //
      value = new FieldValue(getFieldType(valueExpr, fieldEl), extractContent, formatter);
    }

    if (extractContent
        && !value
            .getTargetFieldType()
            .getValueType()
            .getDeepestValueType()
            .getBaseName()
            .equals("BLOB")) {
      throw new IndexerConfException(
          "extractContent is used for a non-blob value at "
              + LocationAttributes.getLocation(fieldEl));
    }

    return value;
  }
  private void buildDynamicFields() throws Exception {
    List<Element> fields = DYNAMIC_INDEX_FIELDS.get().evalAsNativeElementList(doc);
    for (Element fieldEl : fields) {
      String matchNamespaceAttr = DocumentHelper.getAttribute(fieldEl, "matchNamespace", false);
      String matchNameAttr = DocumentHelper.getAttribute(fieldEl, "matchName", false);
      String matchTypeAttr = DocumentHelper.getAttribute(fieldEl, "matchType", false);
      String matchScopeAttr = DocumentHelper.getAttribute(fieldEl, "matchScope", false);
      String nameAttr = DocumentHelper.getAttribute(fieldEl, "name", true);

      WildcardPattern matchNamespace = null;
      if (matchNamespaceAttr != null) {
        // If the matchNamespace attr does not contain a wildcard expression, and its value
        // happens to be an existing namespace prefix, than substitute the prefix for the full URI.
        if (!WildcardPattern.isWildcardExpression(matchNamespaceAttr)) {
          String uri = fieldEl.lookupNamespaceURI(matchNamespaceAttr);
          if (uri != null) matchNamespaceAttr = uri;
        }
        matchNamespace = new WildcardPattern(matchNamespaceAttr);
      }

      WildcardPattern matchName = null;
      if (matchNameAttr != null) {
        matchName = new WildcardPattern(matchNameAttr);
      }

      TypePattern matchTypes = null;
      if (matchTypeAttr != null) {
        matchTypes = new TypePattern(matchTypeAttr);
      }

      Set<Scope> matchScopes = null;
      if (matchScopeAttr != null) {
        matchScopes = EnumSet.noneOf(Scope.class);
        for (String scope : COMMA_SPLITTER.split(matchScopeAttr)) {
          matchScopes.add(Scope.valueOf(scope));
        }
        if (matchScopes.isEmpty()) {
          matchScopes = null;
        }
      }

      // Be gentle to users of Lily 1.0 and warn them about attributes that are not supported
      // anymore
      if (DocumentHelper.getAttribute(fieldEl, "matchMultiValue", false) != null) {
        log.warn(
            "The attribute matchMultiValue on dynamicField is not supported anymore, it will be ignored.");
      }
      if (DocumentHelper.getAttribute(fieldEl, "matchHierarchical", false) != null) {
        log.warn(
            "The attribute matchHierarchical on dynamicField is not supported anymore, it will be ignored.");
      }

      Set<String> variables = new HashSet<String>();
      variables.add("namespace");
      variables.add("name");
      variables.add("type");
      variables.add("baseType");
      variables.add("nestedType");
      variables.add("nestedBaseType");
      variables.add("deepestNestedBaseType");
      if (matchName != null && matchName.hasWildcard()) variables.add("nameMatch");
      if (matchNamespace != null && matchNamespace.hasWildcard()) variables.add("namespaceMatch");

      Set<String> booleanVariables = new HashSet<String>();
      booleanVariables.add("list");
      booleanVariables.add("multiValue");

      NameTemplate name = new NameTemplate(nameAttr, variables, booleanVariables);

      boolean extractContent = DocumentHelper.getBooleanAttribute(fieldEl, "extractContent", false);

      String formatter = DocumentHelper.getAttribute(fieldEl, "formatter", false);
      if (formatter != null && !conf.getFormatters().hasFormatter(formatter)) {
        throw new IndexerConfException(
            "Formatter does not exist: "
                + formatter
                + " at "
                + LocationAttributes.getLocationString(fieldEl));
      }

      boolean continue_ = DocumentHelper.getBooleanAttribute(fieldEl, "continue", false);

      DynamicIndexField field =
          new DynamicIndexField(
              matchNamespace,
              matchName,
              matchTypes,
              matchScopes,
              name,
              extractContent,
              continue_,
              formatter);

      conf.addDynamicIndexField(field);
    }
  }