The MyFaces Tomahawk component library provides a <t:dataTable> component that makes it a little bit easier to implement sortable lists. To use this with Seam's @DataModel / @DataModelSelection annotations, you need to make sure that each time the list is re-sorted, the DataModel is re-created. Here is an example:

In the following Seam component, we are careful to clear out the sortedMessageList each time the sort order changes. The @Factory method ensures that the DataModel is subsequently recreated whenever needed.

@Name("sort")
public class Sort
{
   private String column = "title";
   private boolean ascending = true;
      
   public boolean isAscending()
   {
      return ascending;
   }
   public void setAscending(boolean ascending)
   {
      if ( ascending!=this.ascending ) sortedMessageList=null;
      this.ascending = ascending;
   }
   public String getColumn()
   {
      return column;
   }
   public void setColumn(String column)
   {
      if ( !column.equals(this.column) ) sortedMessageList=null;
      this.column = column;
   }
   
   private void sort(List data)
   {
      Collections.sort(data, new Comparator<Message>() {

         public int compare(Message x, Message y)
         {
            if (!ascending)
            {
               Message temp = y;
               y = x;
               x = temp;
            }
            if ("title".equals(column))
            {
               return x.getTitle().compareTo(y.getTitle());
            }
            else if ("datetime".equals(column))
            {
               return x.getDatetime().compareTo(y.getDatetime());
            }
            else
            {
               return new Boolean( x.isRead() ).compareTo( y.isRead() );
            }
         }
         
      });
   }
   

   private List sortedMessageList;

   @DataModel
   public Object getSortedMessageList()
   {
      return sortedMessageList;
   }
   
   @Factory("sortedMessageList")
   public void init() {
      sortedMessageList= ....; //get the message list!!
      sort(sortedMessageList);
   }
   
   @DataModelSelection
   private Message selectedMessage;
   
   @DataModelSelectionIndex 
   private int indx;
   
   public void print()
   {
      System.out.println(indx + " " + selectedMessage.getTitle());
   }
}

In our JSP code, we can use the component like so:

  <h:form>
     <t:dataTable var="msg" 
                  value="#{sortedMessageList}" 
                  renderedIfEmpty="false" 
                  sortColumn="#{sort.column}" 
                  sortAscending="#{sort.ascending}" 
                  preserveSort="true">
        <h:column>
           <f:facet name="header">
               <t:commandSortHeader columnName="read" arrow="true">
                   <h:outputText value="Read"></h:outputText>
               </t:commandSortHeader>
           </f:facet>
           <h:selectBooleanCheckbox value="#{msg.read}" disabled="true"></h:selectBooleanCheckbox>
        </h:column>
        <h:column>
           <f:facet name="header">
               <t:commandSortHeader columnName="title" arrow="true">
                   <h:outputText value="Title"></h:outputText>
               </t:commandSortHeader>
           </f:facet>
           <h:commandLink value="#{msg.title}" action="#{sort.print}"></h:commandLink>
        </h:column>
        <h:column>
           <f:facet name="header">
               <t:commandSortHeader columnName="datetime" arrow="true">
                   <h:outputText value="Date/Time"></h:outputText>
               </t:commandSortHeader>
           </f:facet>
           <h:outputText value="#{msg.datetime}">
              <f:convertDateTime type="both" dateStyle="medium" timeStyle="short"></f:convertDateTime>
           </h:outputText>
        </h:column>
     </t:dataTable>
  </h:form>