JavaServer Faces

Displaying a Read-Only Table

With Java, you can represent tabular data in many different ways. Commonly, it’s represented as a java.util.List or array with beans or java.util.Map instances representing the columns for each row. If the data is stored in a database, a java.sql.ResultSet or a JSTL javax.servlet.jsp.jstl.sql.Result object typically represents it.

The JSTL <c:forEach> action supports looping over all these data types, with the exception of java.sql.ResultSet, so if all you need is rendering a read-only list or table, you can use JSTL just as you would in a regular JSP page. I actually used this approach in Chapter 8, to verify that the entries added by the action method for the Add button in the report entry form actually were added to the list:

  <%@ taglib uri="http://java.sun.com/jsp/jstl/core" prefix="c" %>
  <ol>
    <c:forEach items="${reportHandler.currentReportEntries}" var="e">
      <li>Date: ${e.date}, Type: ${e.type}, Amount: ${e.amount}</li>
    </c:forEach>
  </ol>

Here the JSP EL expression for the items attribute gets the List of ReportEntry instances returned by the getCurrentReportEntries( ) method in the ReportHandler class:

package com.mycompany.expense; import java.util.Collections; import java.util.Comparator; import java.util.Date; import java.util.List; ... public class ReportHandler { ... public List getCurrentReportEntries( ) { List currentList = currentReport.getEntries( ); Collections.sort(currentList, new Comparator( ) { public int compare(Object o1, Object ...