Performance Improvements

[Bryan Kearney <bk...@avolent.com>]

I have been going through an exercise of tuning an app with Xalan, and
wanted to pass along as an FYI what I did based on a vanilla 2.3.1
installation. 

1) Moved to the nightly buid. Based on a suggestion by Scott Boag I moved to
the nightly build. I saw much better memory usage and could much more easily
move to XSLTc from Xalan./

2) Mave use of the java extension namespace. Some common number, currency,
data formatting was very specific to my application. I found that writing a
java class and calling the extensions using java:myClass sped up the basic
formatting as I do not require the general cases which XSL provided.
However, this seems to make moving to XSLTc a bit harder.

3) Made use of the select attribute of <xsl:variable> instead of a nested
<xsl:value-of>. This was well documented, and saved me a clone each time I
looked up global variables. Since I was using them as global strings and
numbers, this was a good gain.

4) Set the following system properties:

"org.apache.xml.dtm.DTMManager","org.apache.xml.dtm.ref.DTMManagerDefault"
"org.apache.xerces.xni.parser.XMLParserConfiguration","org.apache.xerces.par
sers.StandardParserConfiguration"

These properties, if not set, cause Xalan to load up the jars looking for
the factory. This increased IO and did so withing sycnhronized methods.


-- bk