Re: [xsl] JAXP Transformer contract

[Johannes Döbler <jd at aztecrider dot com>]

>Saxon comes with a SaxonServlet.java that demonstrates a caching pattern
>using a HashTable, and it seems to work well. Can someone email me
>off-list with the design pattern for "pooling" objects such as
>Transformer? I am assuming this means you have several Transformer
>objects available, to make up for the lack of thread safety... if you
>need one, it won't give you one unless it is believed to not be in use?
>
>    - Mike

In database programming this pattern is known as ConnectionPool, but one 
can easily extend ot to all kind of shared resources. Wikis Pattern 
Repository's (http://c2.com/cgi/wiki?ConnectionPatterns) has some useful 
material about it.


>Remarkably well considering how simplistic it is: it just accumulates
>compiled stylesheets in the "cache" until you clear them all out. None of
>those fancy LRU discard algorithms designed for poor souls with finite
>amounts of memory...
>
>Mike Kay

never heard of an unfinite amount of memory :-)
But the caching problem has a simpler solution: Just use a xslt 
implementation with a threadsafe stylesheet object. (Of course TrAX does 
not suppose thread safety - but that's just the mess with an API designed 
after implementations were created).

Johannes


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