struts2: how to invoke a method from the xml conf file. what shoud be the type?

[Peter Primrose]

how can i invoke a method from the configuration xml file?

    
<action name="admin_*" method="{1}" class="com.struts.security.admin.AdminAction">
  <result name="userList" type="tiles">admin_userList</result> 
  <result name="email"   type="tiles">emailSettings</result>
  <result name="newRegistered"   type="tiles">newRegisteredUsers</result>
  <interceptor-ref name="user" /> 
  </action>
 

the userList, in the example above, should invoke a method instead of showing the page. I wonder what is the TYPE in need to use.

thanks