Dynamic Menus in RichFaces

RichFaces has no built-in functionality for creating dynamic menus, the reason for this could be that a lot of different use case scenarios require different type of dynamic menus. This example presents the most simple case: The menu items are dynamically populated from a list, and an action method is called with the id of the menu item, when the user selects the menu item.

The data of a menu item is represented by the MenuItem class:

public class MenuItem {

 /**
  * Id of the menu item
  */
 private int id;

 /**
  * Label for menu item
  */
 private String label;

 /**
  * Constructor
  * 
  * @param label The label fo the menu item
  * @param id the id of the menu item
  */
 public MenuItem(String label, int id) {
  super();
  this.label = label;
  this.id = id;
 }

 /**
  * @return the id
  */
 public int getId() {
  return this.id;
 }

 /**
  * @return the label
  */
 public String getLabel() {
  return this.label;
 }

 /**
  * @param id
  *            the id to set
  */
 public void setId(int id) {
  this.id = id;
 }

 /**
  * @param label
  *            the label to set
  */
 public void setLabel(String label) {
  this.label = label;
 }

 /**
  * @see java.lang.Object#toString()
  */
 @Override
 public String toString() {
  StringBuilder builder = new StringBuilder();
  builder.append("MenuItem [id=");
  builder.append(this.id);
  builder.append(", label=");
  builder.append(this.label);
  builder.append("]");
  return builder.toString();
 }

}

The dynamic menu is supported by the DynamicMenu class. It provides the list of menu items and an action method:

import java.util.ArrayList;
import java.util.List;

import org.apache.log4j.Logger;
import org.jboss.seam.annotations.Name;

@Name("dynMenu")
public class DynamicMenu {
 
 private Logger log = Logger.getLogger(DynamicMenu.class.getName());

 /**
  * Example action method
  * 
  * @param id the menu item id
  */
 public void action(int id) {
  log.info("Action called with menu item id: " + id);
 }

 /**
  * Returns the list of menu items.
  * 
  * @return the list of menu items
  */
 public List getMenuItems() {

  List menuItems = new ArrayList();

  menuItems.add(new MenuItem("Menu Item #1", 1));
  menuItems.add(new MenuItem("Menu Item #2", 2));
  menuItems.add(new MenuItem("Menu Item #3", 3));

  return menuItems;
 }
}

The following code snippet contains the dynamic menu xhtml example. The key in the dynamic menu items is the <c:forEach> iterator. The namespace declaration is very important, it should be xmlns:c="http://java.sun.com/jstl/core". If you use xmlns:c="http://java.sun.com/jsp/jstl/core" namespace, the iterator won't work!

<h:form xmlns:h="http://java.sun.com/jsf/html">

...

   <rich:dropDownMenu
    value="Dynamic Menu Item Example"
    style="text-decoration: none;"
   >


    <c:forEach xmlns:c="http://java.sun.com/jstl/core"
     var="item"
     items="#{dynMenu.getMenuItems()}"
    >

     <rich:menuItem
      id="menuItem#{item.id}"
      submitMode="ajax"
      value="#{item.label}"
      action="#{dynMenu.action(item.id)}"
     >

     </rich:menuItem>
    </c:forEach>



   </rich:dropDownMenu>

...

</h:form>