Hi,
my last (proposed) addition of a system property controlling rendering
(PDFBOX-4309) adds to other already existing properties (e.g.
org.apache.pdfbox.rendering.UsePureJavaCMYKConversion, possible more?).
These settings are important for specific use cases/environments. Even
more they are often only needed for specific PDF documents - e.g. the
mentioned properties especially cure a problem with excessive calls to
Java color management implementation, without them some documents are
practically not processable. In other cases the settings also could have
negative effects like slower processing or wrong colors.
Thus it would be good to have the possibility to adjust settings on a
per-document basis (either directly by user or based on
checking/collecting document features like number of images etc.).
The problem is how these document specific settings can be provided to
the relevant classes, e.g. PDICCBased.
Providing a settings object through the call-chain is probably not an
option as a lot of constructors/methods would have to be changed for
only a few places where the settings are really needed.
One viable solution which came to my mind is using a ThreadLocal
ProcessingProperties map (String,String). In order to not get unwanted
side-effects using these properties should be initiated by the user
and it should be clearly documented to do it in a try-finally block in
order to remove the settings after processing (and also to not get
memory leaks etc.), like:
try {
LocalProcessingProperties.activate(); // creates a map object
... // PDF processing
} finally {
LocalProcessingProperties.clear(); // removed map object
}
A call to LocalProcessingProperties.getProperty( KEY ) would return
value from ThreadLocal map - if map exists and contains this key,
otherwise fall back to return System.getProperty( KEY ).
As PDFBOX (currently) doen't use multiple threads this should work fine
- for multi-threaded usage an initialization/clear would be needed for
each thread which could get the reference to the map object of the main
processing thread.
WDYT?
Best regards,
Timo
--
Timo Boehme
OntoChem IT Solutions GmbH
Blücherstraße 24
06120 Halle (Saale)
Germany
phone: +49 345 478 047 4 | fax: +49 345 478 047 1
email: [email protected] | web: www.ontochem.com
HRB 21962 Amtsgericht Stendal | USt-IdNr.: DE815563824
managing director : Lutz Weber
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