Request/session objects - Best Practice

Question

I have a simple scenario which I think other people will recognise, and am wondering what the best pattern to use in JSF is:
I have a summary page which displays orders for the current user in a dataTable. This has a backing bean called orders.
When the user clicks on an order, it calls an action on the orders object which fetches the specific order from the database and navigates to a second page to display details about the order.
I don't mind the orders object being a session bean, but I don't really want the order bean to be session, it needs to be a request bean.
How do I place the order bean somewhere so that it is a request bean on the second page?
In ASP.NET I could place it in the ViewState before transferring control to the second page, or temporarily put it on the session, then pull it off the session when the second page loads the first time.
The problem with putting the order object in the session is that it never goes away, and might be confused if the user has multiple browser windows open trying to look at 2 orders at the same time.

Answer 1

Here's the way I do this kind of thing.
In this case, I'd have a session bean called orders. It's got an orders property that will return all the orders for display in a dataTable. It's got a reference to a session-scoped bean that contains the id of the currently selected order. When the user selects an order (typically by clicking a commandLink) the id of the selected order is set in a session scoped bean called orderDetailsOptions and the user is navigated to the order details page. I'd have a Refresh button on the page that causes the orders to be reloaded.
public class OrdersBean {
  private OrderDetailsOptionsBean orderDetailsOptions;
  private DataModel orders;
  private void reset() {
    orders = null;
  public OrdersBean() {
    reset();
  public void setOrderDetailsOptions( OrderDetailsOptionsBean orderDetailsOptions ) {
    this.orderDetailsOptions = orderDetailsOptions;
  public DataModel getOrders() {
    if ( orders == null ) {
      ResultSet rs = doQuery();
      orders = new ResultDataModel( ResultSupport.toResult( rs ) );
    return orders;
  /* Actions */
  public String orderSelected() {
    Map row_data = (Map) orders.getRowData();
    String order_id = orders.get( "orderId" );
    orderDetailsOptions.setOrderId( order_id );
    reset();
    return "toOrderDetails";
  public String refresh() {
    reset();
    return "success";
}The OrderDetailsOptionsBean for the session holds the id of the currently selected order.
public class OrderDetailsOptionsBean {
  private String order_id;
  public void setOrderId( String order_id ) {
    this.order_id = order_id;
  public String getOrderId() {
    return order_id;
}The OrderDetailsBean is a request bean to get the details for the selected order.
public class OrderDetailsBean {
  private OrderDetailsOptionsBean options;
  private String order_id = null;
  private Map fields = null;
  public void setOptions( OrderDetailsOptionsBean options ) {
    this.options = options;
  public String getOrderId() {
    if ( order_id == null ) {
      order_id = options.getOrderId();
  public Map getFields() {
    if ( fields == null ) {
      getOrderId();
      // Do the query.
    return fields;
}Then here's what's in faces-config for this:
<managed-bean>
  <managed-bean-name>orders</managed-bean-name>
  <managed-bean-class>OrderBean</managed-bean-name>
  <managed-bean-scope>session</managed-bean-scope>
  <managed-property>
    <property-name>orderDetailsOptions</property-name>
    <property-class>OrderDetailsOptionsBean</property-class>
    <value>#{orderDetailsOptions}</value>
  </managed-property>
</managed-bean>
<managed-bean>
  <managed-bean-name>orderDetailsOptions</managed-bean-name>
  <managed-bean-class>OrderDetailsOptionsBean</managed-bean-name>
  <managed-bean-scope>session</managed-bean-scope>
</managed-bean>
<managed-bean>
  <managed-bean-name>orderDetails</managed-bean-name>
  <managed-bean-class>OrderDetailsBean</managed-bean-name>
  <managed-bean-scope>request</managed-bean-scope>
  <managed-property>
    <property-name>options</property-name>
    <property-class>OrderDetailsOptionsBean</property-class>
    <value>#{orderDetailsOptions}</value>
  </managed-property>
</managed-bean>
<navigation-rule>
  <from-view-id>orders.jsp</from-view-id>
  <navigation-case>
    <from-outcome>toOrderDetails</from-outcome>
    <to-view-id>orderDetails.jsp</to-view-id>
    <redirect />
  </navigation-case>
</navigation-rule>