Re: FreeMarker Processing Pipeline

I'm not entirely sure what do you consider a "processing pipeline",  
but I'll take a guess...

- template source code is pulled from whatever resources by an  
instance of a class implementing freemarker.cache.TemplateLoader
- (there is a MultiTemplateLoader to multiplex several loaders into one)
- TemplateLoader is owned by a freemarker.cache.TemplateCache and used  
to load template source code on demand. TemplateCache will also create  
a new Template object and pass it its source code; and store the  
constructed Template object for later retrieval. The Template object  
builds the AST from its source code and stores it internally.
- TemplateCache is owned by a Configuration object.

When you render output through a Template, you invoke the  
Template.process(), passing it the data model and an output writer.  
Under the cover, a thread local object, freemarker.core.Environment is  
created, which act as the context for the duration of that particular  
process() invocation and coordinates the rendering to the writer.

If you want a preprocessor, your best bet (at least in 2.3.x codebase)  
is to create a TemplateLoader that wraps another one, and edits the  
source code of the templates. In the 2.4.x codebase, there is an AST  
visitor API that you can use to do logical transformation on the AST  
level; you register the AST visitors with the Configuration, and  
they're each given a chance to manipulate the AST after it's initially  
constructed.

Attila.

On 2008.05.28., at 21:15, mraible wrote:

>
> Is the FreeMarker Processing Pipeline documented somewhere. It would  
> be very
> useful to see a diagram. The reason I'm asking is because I'd like  
> to insert
> a pre-processing phase. I have a templating framework that allows  
> replacing
> standard HTML tags, i.e.  ,  , etc. with macros, jsp tags or  
> whatnot. I'd
> like to use it with FreeMarker to simplify page authoring for web
> developers.
>
> Thanks,
>
> Matt


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