docs: @Override
  	protected void doProcess(ITemplateContext context, IProcessableElementTag tag, AttributeName attributeName,
  			String attributeValue, IElementTagStructureHandler structureHandler) {
  		final IEngineConfiguration configuration = context.getConfiguration();
  
          /*
           * Obtain the Thymeleaf Standard Expression parser
           */
          final IStandardExpressionParser parser =
                  StandardExpressions.getExpressionParser(configuration);
  
          /*
           * Parse the attribute value as a Thymeleaf Standard Expression
           */
          //final IStandardExpression expression = parser.parseExpression(context, attributeValue);
  
          // get field name.
          String fieldname = tag.getAttributeValue(null, "name");
  
          // get field value from struts2 ognl
          Object parameterValue = getFieldValue(fieldname);
          if ( parameterValue != null ) {
          	structureHandler.setAttribute("value", HtmlEscape.escapeHtml5(parameterValue.toString()));
          }
          if ( !hasFieldError(fieldname)) {
          	return;
          }
  
          // add field-error css class.
          IAttribute cssClass = tag.getAttribute("class");
          String css = cssClass.getValue();
          if ( StringUtils.isBlank(css)) {
          	structureHandler.setAttribute("class", fieldErrorClass(tag));
          } else {
          	structureHandler.setAttribute("class", fieldErrorClass(tag) + " " + css);
          }
      }