About SiteMesh
SiteMesh is a web-page layout and decoration framework and web- application integration framework to aid in creating large sites consisting of many pages for which a consistent look/feel, navigation and layout scheme is required.
The framework integrates well with SiteMesh "out of the box".
The framework stores all its value stack information in the request attributes, meaning that if you wish to display data that is on the stack (or even the ActionContext), you can do so by using the normal tag libraries that come with the framework. That's it!
ActionContextCleanUp
Under the framework's Architecture, the standard filter-chain optionally starts with the ActionContextCleanUp filter, followed by other desired filters. Lastly, the FilterDispatcher handles the request, usually passing it on to the ActionMapper. The primary purpose of the ActionContextCleanUp is to provide SiteMesh integration. The clean-up filter tells the dispatcher filter exactly when to remove obsolete objects from the request. Otherwise, the ActionContext may be removed before the decorator attempts to access it.
Order Matters
If ActionContext access is required within the decorators, the ActionContextCleanUp filter must be placed at the beginning of the filter-chain.
Javadoc: (org.apache.struts.action2.dispatcher.ActionContextCleanUp)
Velocity and FreeMarker Decorators
The framework provides an extension of the SiteMesh PageFilter to assist with integration with Velocity and FreeMarker. Our filters provide the standard variables and Struts Tags that you used to create views in your favorite template language.
Velocity
The VelocityPageFilter extends the SiteMesh PageFilter to allow direct access to framework variables such as $stack and $request.
In the web.xml, the VelocityPageFilter should be placed between the ActionContextCleanUp and the {FilterDispatcher}}.
FreeMarker
The FreeMarkerPageFilter extends the SiteMes PageFilter to allow direct access to framework variables such as $stack and $request.
In the web.xml, the VelocityPageFilter should be placed between the ActionContextCleanUp and the {FilterDispatcher}}.
Javadoc: (example.freemarker.filter.chain)