XSLT Compilers
One drawback to XLST stylesheets is performance. An XLST processor, such as XALAN, must read in the stylesheet and build an internal structure representing the rules that must be applied. The processor must then read in the XML document and match each element to the rules defined in the stylesheet and generate the required output. All of this takes time.
One way to improve performance is to preprocess the stylesheet to create a custom program that will apply the one stylesheet to an XML document in an efficient manner.
Such a technology is called an XSLT compiler. This is a fast changing area of XSL technology, but the original XSLT compiler, called xsltc, developed by Sun Microsystems is now developed and maintained by the Apache project.
Apache provides the xsltc compiler used to compile an XSL stylesheet into a translet (a set of Java classes). An associated runtime processor is used to apply the compiled translet to an XML document and perform the XML document transformation.
An XSLT translet can be invoked from the command line or included in a developer's application.
The XLST compiler technology is very new and still maturing (and changing) as this book is being written in late 2001. For more information and to download the xsltc technology, take a look at the XALAN pages on the Apache Web site at