getRowCount() of IBasicTableModel run 4 times????

[Huang Gehua]

This is my code:
=======================
<span jwcid="[EMAIL PROTECTED]:TableView" source="ognl:allPerson"
columns="selected,userInfo,communication"
 pageSize="10"
 tableSessionStateManager="ognl:new
org.apache.tapestry.contrib.table.model.common.FullTableSessionStateManager
()">
   <table>
   <tr jwcid="@contrib:TableRows" row="ognl:row">
       <td jwcid="@contrib:TableValues" />
   </tr>
   </table>
   <span jwcid="@contrib:TablePages" />
</span>
========================
   public IBasicTableModel getAllPerson()throws CnbrnException{
       return new IBasicTableModel(){
           public int getRowCount(){
               return
getRelationshipService().getFriendsCount(getCurrentUser().getId(),new
Integer(1));
           }

           public Iterator getCurrentPageRows(
                   int nFirst,
                   int nPageSize,
                   ITableColumn objSortColumn,
                   boolean bSortOrder){
                   ..........
                }
           }
       };
   }
=====================================
When i run the application and request this page i found that the
"getRowCount()" method runs 4 times!!!???  What's wrong with my code? And
how let this method runs only once???
I was used Tapestry-contrib 4.0.
Any advice was welcome!!!!