code: @Override
      public int doEndTag() throws JspException {
          Tag t = findAncestorWithClass(this, TransformSupport.class);
          if (t == null) {
              throw new JspTagException(
                      Resources.getMessage("PARAM_OUTSIDE_TRANSFORM"));
          }
          TransformSupport parent = (TransformSupport) t;
  
          Object value = this.value;
          if (value == null) {
              if (bodyContent == null || bodyContent.getString() == null) {
                  value = "";
              } else {
                  value = bodyContent.getString().trim();
              }
          }
          parent.addParameter(name, value);
          return EVAL_PAGE;
      }
docs: simply send our name and value to our parent <transform> tag