AJAX and <f:param>

The <f:param> tag can be used to pass request parameters to a managed bean. Since we have discussed this tag in detail in Chapter 2, Communication in JSF, we can continue here with an example of using it inside <f:ajax>:

<h:form>
  <h:inputText id="nameInputId" value="#{ajaxBean.name}"/>
  <h:commandButton value="Send" action="#{ajaxBean.ajaxAction()}">
    <f:ajax execute ="nameInputId" render="nameOutputId">
      <f:param name="surnameInputId" value="Nadal"/>
    </f:ajax>
  </h:commandButton>
  <h:outputText id="nameOutputId" value="#{ajaxBean.name}"/>
</h:form>

Remember that the parameter that was passed is available in the request parameter map:

FacesContext fc = FacesContext.getCurrentInstance();
  Map<String, String> params = 
             fc.getExternalContext().getRequestParameterMap();
  logger.log(Level.INFO, "Surname: {0}", params.get("surnameInputId"));

Note

Keep in mind that <f:param...