Hmm, there are lies, damn lies and statistics. While I don't dispute the 30%
let's see the probable causes for this:
- iText tries to do things correctly avoiding to cut corners that will come and
bite your later. Metadata writing, appearance generation and so on.
- iText is a generic PDF library. It reads, writes and modifies PDFs. Any
library designed with a narrower purpose can optimize the interested areas to
perform better.
- iText comes with source and can be extended, modified, altered. This implies
that a sensible and probably heavier structure must be in place to allow that.
If you have a closed source library with just a single purpose things can be
done faster as that's all it's going to do.
- com.itextpdf.text.pdf.PdfStamperImpl.close() is where everything is written
to file, if you avoid calling this nothing will come out.
- There are some speed and memory improvements in the pipeline but I don't know
how much % improvement will result or in what areas.
Paulo
________________________________
From: Azùa Giovanni (KSXD 32) [[email protected]]
Sent: Tuesday, April 20, 2010 1:12 PM
To: Post all your questions about iText here
Subject: [iText-questions] performance question
Hello,
For a specific Letter generation use-case I prepared a test of statistical
significance using a paired t-test for comparing the performance [1] of iText
vs a commercial PDF framework. The experiment shows that for our relevant
use-case iText underperforms by 30% with 95% confidence.
I did some further investigation of the iText code for this specific use-case
and found the following call to be among the top most expensive calls:
com.itextpdf.text.pdf.PdfStamperImpl.close (line 189) taking up to 195
milliseconds
The code that invokes such method is the following:
private static void appendFooter(PdfWriter writer) throws Exception {
Map<String, String> replacements = new HashMap<String, String>();
replacements.put("ph0001", "XXXXX XXXXX");
replacements.put("ph0002", "Head of Customer Acquisition");
replacements.put("ph0003", "XXXXXX XXXXXXX");
replacements.put("ph0004", "Head of Customer Satisfaction");
PdfReader footerReader = new PdfReader(FOOTER_PATH);
ByteArrayOutputStream outputStream = new ByteArrayOutputStream();
PdfStamper stamper = new PdfStamper(footerReader, outputStream);
AcroFields form = stamper.getAcroFields();
for (Map.Entry<String, String> entry : replacements.entrySet()) {
form.setField(entry.getKey(), entry.getValue());
}
stamper.setFormFlattening(true);
stamper.close();
int pageOne = 1;
int xOffset = 5;
int yOffset = -560;
PdfReader memoryReader = new PdfReader(outputStream.toByteArray());
PdfImportedPage importedPage = writer.getImportedPage(memoryReader,
pageOne);
PdfContentByte content = writer.getDirectContent();
content.addTemplate(importedPage, xOffset, yOffset);
}
Are there any possible rewrites to avoid the expensive call?
Thanks in advance,
Best regards,
Giovanni
[1] The Art of Computer Systems Performance Analysis: Techniques for
Experimental Design, Measurement, Simulation, and Modeling
http://www.amazon.com/Art-Computer-Systems-Performance-Analysis/dp/0471503363/ref=cm_cr-mr-title
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