[gatein-dev] Groovy template engine rewrite

In my optimization effort I have rewritten the Groovy Template engine from scratch. The previous engine was a fork of the basic SimpleTemplateEngine in the Groovy package (why it was forked ? I haven't had an answer so far). One part of the optimization consist into translating the markup chunks of the template directly into UTF-8 encoded bytes so it can be directly written on the Servlet output stream. Actually if you think about it, on every request constants character data (the markup chunks) are converted into byte using the UTF-8 encoding. So it has 2 nasty effects: 1/ encoding a char into a byte[] (some chars take several bytes) is costly specially if the Servlet engine do it for you (as it is possible to optimize it and that's what we do in other parts of GateIn) 2/ unnecessary serialization as when you encode the string GateIn basically you - write the char[] on the Writer - tomcat read the char[] - tomcat translate each char into a byte[] - the corresponding byte[] is written to the output (with usually an additional buffer) The Groovy markup chunk optimization computes the byte[] and write them to the servlet output, removing the cost of doing the translation to byte[] (encoding) and a read/write of the array (serialization). The second part of the optimization is to pre parse directly the Groovy strings (known as GString). As you may know in Groovy it is possible to have $foo or ${foo} into the markup which cause an evalutation of the string. The new template compiler pre parse that into expression and markup chunks. The benefit of template rewrite in the capability to maintain a table of template line number to groovy line number which allowed me to implement more precise error reporting when an exception occurs, for instance: 1. abc <% throw new Exception(); %> def is compiled into Groovy like: 1. out.print("abc"); 2. throw new Exception(); 3. out.print("def"); So when the exception occurs, Groovy say the error happened at line 2 but what interest us is where it happened in the template file. So I have been able to craft that into the engine and normally it should work better (I'm saying that because I have unit tests but I'm not 100% sure that I cover all cases). cheers Julien