The Java EE 5 Tutorial

UIData Properties

UIData components must be bound to one of the types listed in Table 12–1. The UIData component from the bookshowcart.jsp page of the Duke’s Bookstore example is discussed in the section Using Data-Bound Table Components. Here is part of the start tag of dataTable from that section:

<h:dataTable  id="items"
    var="item" >

The value expression points to the items property of the ShoppingCart bean. The ShoppingCart bean maintains a map of ShoppingCartItem beans.

The getItems method from ShoppingCart populates a List with ShoppingCartItem instances that are saved in the items map from when the customer adds books to the cart:

public synchronized List getItems() {
    List results = new ArrayList();
    return results;

All the components contained in the UIData component are bound to the properties of the ShoppingCart bean that is bound to the entire UIData component. For example, here is the outputText tag that displays the book title in the table:

<h:commandLink action="#{showcart.details}">
    <h:outputText value="#{item.item.title}"/>

The book title is actually a hyperlink to the bookdetails.jsp page. The outputText tag uses the value expression #{item.item.title} to bind its UIOutput component to the title property of the Book bean. The first item in the expression is the ShoppingCartItem instance that the dataTable tag is referencing while rendering the current row. The second item in the expression refers to the item property of ShoppingCartItem, which returns a Book bean. The title part of the expression refers to the title property of Book. The value of the UIOutput component corresponding to this tag is bound to the title property of the Book bean:

private String title = null;
public String getTitle() {
    return this.title;
public void setTitle(String title) {