Raible Designs

Tiles Tips o' the Day

Here's a couple of things I learned today that might be useful to you Struts developers out there. When using Tiles, you'll normally import all the attributes into your baseLayout.jsp, and then your attributes are exposes as beans/scripting variables (you can actually grab them with JSTL tags). Rather than using:

<tiles:importAttribute/>

Use:

<tiles:importAttribute scope="request"/>

And then all your inserted pages can access these attributes. Pretty slick when you got a little JSTL love in the mix. The second tip is how to implement definition path switching. Let's look at the following baseLayout definition as an example:

  <definition name=".baseLayout" path="/layouts/baseLayout.jsp">
    <put name="titleKey"/>
    <put name="header" value="/common/header.jsp"/>
    <put name="sidebar" value=".sidebar"/>
    <put name="footer" value="/common/footer.jsp"/>
  </definition>

You currently cannot change the "path" attribute with a Controller, so you have to do it as the Tiles author recommends - by changing your path to refer to an action. So I changed the path on this particular definition to be:

<definition name=".baseLayout" path="/do/switchLayout">

Where my action-mapping is defined as follows:

 <action path="/switchLayout" 
   type="org.appfuse.webapp.action.SwitchLayoutAction">
   <forward name="printLayout" path="/layouts/printLayout.jsp" />
   <forward name="baseLayout" path="/layouts/baseLayout.jsp" />
 </action>

Then in SwitchLayoutAction.java, I have the following code:

boolean print =
    Boolean.valueOf(request.getParameter("print")).booleanValue();

// see if a print parameter is passed in the request
if (print) {
    log.debug("switching base layout to printing...");

    return mapping.findForward("printLayout");
} else {
    return mapping.findForward("baseLayout");
}

Pretty slick IMO! It's easy to make the printLayout.jsp only contain some simple wrapper stuff and only do <tile:insert attribute="content"/>. Of course, in this particular example, you could just use a print stylesheet (media="print"), but that doesn't work so well on 4.x browsers (man I hate those beotches).