[Yanel-dev] XSLT only if XSL has changed

[Michael Wechner]

I have added an issue to github about it

https://github.com/wyona/yanel/issues/67

Thanks

Michael

Am 01.03.14 20:51, schrieb Michael Wechner:
> Dear Balz
>
> If I understand correctly using Templates helps to prevent re-parsing of
> XSLTs, also
> when using include/import.
>
> I don't have experience myself with it, but maybe we can try to improve
> this somehow together
>
> Have a nice weekend
>
> Michael
>
> Am 28.02.14 18:42, schrieb basZero:
>> Thanks Michael,
>> yes I was exactly having that section of code in mind in the
>> BasicXMLResource.java:
>>
>> xsltHandlers[i] = tf.newTransformerHandler(uriResolver.resolve(xsltPath,
>> xsltPath));
>>
>> As far as I understand, this is not yet the transformation itself, it is
>> the building of the transformer object.
>> I measured a bit today and realized that for each include / import
>> statement, it fully parses the included file again, even if it has already
>> been parsed in that cycle.
>>
>> So I think too many includes will slow down overall performance of the XSLT.
>>
>> Cheers, Bas
>>
>>
>> On Fri, Feb 28, 2014 at 10:31 AM, Michael Wechner <michael.wechner at wyona.com
>>> wrote:
>>>  Hi Balz
>>>
>>> Please see my comments inline below
>>>
>>> Am 28.02.14 10:08, schrieb basZero:
>>>
>>> Hi,
>>>
>>> as you know, Yanel performs the XSLT (Transformation of XSL to temporary
>>> Java Class) for EACH request.
>>>
>>> I would like to ask, whether there is anybody out there who has played with
>>> these two alternative approaches:
>>>
>>> 1) extend XSLT Processor in a way, that it keeps a list of XSLs including
>>> timestamps and only does the transformation, if the XSL has changed. Hence:
>>> reuse the java classes from earlier if nothing changed.
>>>
>>>
>>> At the moment we use
>>>
>>> <dependency groupId="xalan" artifactId="xalan" version="2.7.0"/>
>>>
>>> but I am not sure whether what you are asking has actually anything to do
>>> with Xalan itself, but
>>> rather how we instantiate the XSLTs inside
>>>
>>>
>>> src/impl/java/org/wyona/yanel/impl/resources/BasicXMLResource.java
>>>
>>> It seems to me that we would have to introduce so called Templates as
>>> described in
>>>
>>>
>>> http://www.javaworld.com/article/2073394/java-xml/transparently-cache-xsl-transformations-with-jaxp.html
>>>
>>> Maybe you can give it a try.
>>>
>>> Independent of the caching the following performance hints might also
>>> improve your situation
>>>
>>> https://xalan.apache.org/old/xalan-j/faq.html#faq-N10175
>>>
>>> HTH
>>>
>>> Michael
>>>
>>>  This option would still have the advantage that you can change/patch XSL
>>> files in the running system and see the changes immediately.
>>>
>>> 2) There is an official XSLT processor mode called "cached". In this mode,
>>> the XSLT processor only performs the XSLT once and keeps the generated java
>>> classes for the lifetime of the JVM. This is certainly the fastest way of
>>> having XSLT in a system, but any changes to XSLs are of course ignored once
>>> the XSLT has happened. So this is a disadvantage.
>>>
>>> I would be interested in some hands-on experience for option 1).
>>>
>>> Cheers, Bas
>>>
>>>
>>>
>>>
>>>
>>>
>>> --
>>> Yanel-development mailing list Yanel-development at wyona.com
>>> http://lists.wyona.org/cgi-bin/mailman/listinfo/yanel-development
>>>
>>
>
>
>

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