Hi Juan,
I have multiple threads reading PDF files, although not trying to process
kids asynchronously. Here's some excerpts. I guess that to get the
underlying PDDocument handle, you should extend PDFTextStripperByArea.
Frank
<code>
public static Thread parsePDF() {
return new Thread(() -> {
List<String[]> result;
try {
result = new PDFTableStripper().parse(sourceFilename);
} catch (IOException ex) {
log.fatal("Failed to read " + sourceFilename);
log.fatal(ex.getMessage(), ex);
return;
}
// Process result here
log.info("Finished");
}, "Parse PDF");
}
public class PDFTableStripper extends PDFTextStripper {
private ArrayList<String[]> result;
public PDFTableStripper() throws IOException {
super();
setLineSeparator("\n");
setPageEnd("\f");
result = new ArrayList<>(0);
}
/**
* Convenience method to parse the specified PDF file.
*
* @param filepath Full path to file
* @return List of String[]s containing one String[] entry for each row
in the table. Each
* row is an array of Strings, with one entry for each column in the
table.
* @throws IOException
*/
public List<String[]> parse(String filepath) throws IOException {
document = PDDocument.load(filepath);
getText(document);
document.close();
return result;
}
}
</code>
On Wed, Dec 3, 2014 at 7:41 AM, Juan M Uys <[email protected]> wrote:
> Hello,
>
> From the FAQ about PDFBox being thread safe, it says one can have multiple
> threads each accessing their own PDDocument object.
>
> I have a question about this. Here's some pseudo Scala code I use to load a
> document, find its children, then parse those children using a
> PDFTextStriperByArea:
>
> <code>
> val pdf = PDDocument.load(new File("/path/to/pdf"), true)
> val cos = pdf.getDocumentCatalog().getPages().getCOSObject()
> val kids = cos.getDictionaryObject(COSName.KIDS).asInstanceOf[COSArray]
>
> // some logic to iterate through the children by index i:
> val kid: COSDictionary = kids.getObject(i)
> // XXX
> if (COSName.PAGE.equals(kid.getDictionaryObject(COSName.TYPE))) {
> // definitely a kid. Process!
> // ... set up the stripper, set up bounding boxes, etc ...
> stripper.extractRegions(new PDPage(kid))
> }
> </code>
>
> The thing is, at point XXX I want to send the 'kid' off to another thread
> for asynchronous processing.
>
> How would I go about getting a handle on the underlying file as loaded by
> PDDocument?
> Do I just instantiate a PDDocument in each async thread and get the i-th
> kid then process it?
> I've tried this, but get "Too many open files".
>
> Any good examples of how this can be done?
>
> Thank you,
> Juan
>
