code: public int doStartTag() throws JspException {
  	DataSourceWrapper ds = new DataSourceWrapper();
  	try {
  	ds.setDriverClassName(getDriverClassName());
  	}
  	catch (Exception e) {
  	    throw new JspTagException("Invalid driver class name: " +
  		e.toString(), e);
  	}
  	ds.setJdbcURL(getJdbcURL());
  	ds.setUserName(getUserName());
  	ds.setPassword(getPassword());
  	pageContext.setAttribute(var, ds, scope);
  	return SKIP_BODY;
      }
docs: Tag logic