[SOLVED] PHP-like output buffering in JSP (letting subtemplates influence the master template)

PHP-like output buffering in JSP (letting subtemplates influence the master template)

In my website I have a master JSP template:

<html>
 <body>
  <nav>...</nav>
  <tiles:insertAttribute name="body" />
  <footer>...</footer>
 </body>
</html>

And multiple page templates:

<p>This is content</p>

Now I'd like the page templates to be able to define some Javascript and CSS includes, so the page templates must be executed before the <head> of the master template.

In PHP I could use output buffering for this:

<? ob_start()
   include $slave;
   $body = ob_get_clean(); ?>
<html>
 <head>
 <? foreach($javascripts as $script) ?>
     <script src="<?=$script?>" />
 <? endforeach ?>
 <body>
  <nav>...</nav>
  <?=$body?>
  <footer>...</footer>
 </body>
</html>

Is there a similar technology available in JSP? Or else another way to achieve what I need? I'm using it in Spring MVC 3 + Apache Tiles

Solution

You could just define an additional attribute (blank by default) in your tiles definition, and insert this attribute inside the head section of the layout page. That's how Tiles is supposed to work.

Or you could use Sitemesh instead of Tiles, which does what you suggest: it uses a filter which buffers the response, and then decorates the response by extracting some of its elements and putting them into a template.

I guess it could be possible to use Sitemesh and Tiles together, but it would become a bit too complex, IMHO.