How to call external URL from OAF

public void processRequest(OAPageContext pageContext, OAWebBean webBean)
{
super.processRequest(pageContext, webBean);

String ExternalUrl = pageContext.getParameter(“ExternalUrl”);

if ((ExternalUrl != null) || (!””.equals(ExternalUrl)))
{
String extrnlurl = “function externalurlfunc(){document.location='”+ExternalUrl+”‘;}”;
OABodyBean bodyBean = (OABodyBean)pageContext.getRootWebBean();
pageContext.putJavaScriptFunction(“externalurlfunc”, extrnlurl);
String URL = “javascript:externalurlfunc();”;
bodyBean.setOnLoad(URL);

}
else {
throw new OAException(“Error In External URL”,OAException.ERROR);
}
}