Injecting page-height to the FopFactory without creating a new instance

[Arpit Phanda <ph...@gmail.com>]

Hi,

We are migrating our service from apacheFOP-0.95 to apacheFOP-2.1. Our aim
is to configure pageHeight and pageLength to singleton instance during each
rendering call.

In earlier version we could create FopFactory instance by calling
FopFactory.newInstance() and then use setPageHeight/setPageWidth on the
same instance of FopFactory. Currently, this is no more valid. Now, we are
allowed to set these property on FopFactoryBuilder - new
FopFactoryBuilder().setPageHeight().build() which means we are creating a
new FopFactory instance each time. Is there any way of injecting these
property on already created instance.

PS: Also, i read a few issue where it has been said ApacheFOP is not
threadsafe and just wanted to know the reason behind it.

-- 
Regards
Arpit Phanda

Re: Injecting page-height to the FopFactory without creating a new instance

[Alexios Giotis <al...@gmail.com>]

Hi Arpit,

This change was intentionally done, see 
https://wiki.apache.org/xmlgraphics-fop/FopFactoryConfiguration <https://wiki.apache.org/xmlgraphics-fop/FopFactoryConfiguration>

The problem is that FopFactory can’t be thread safe and at the same time allow changes in configuration. In the past, FopFactory was reusable but not thread-safe. Related to “PS”, we are using FOP 2.1 in several production servers, each one rendering up to 100 documents at the same time and we don’t have any issue related to thread safety. 


I assume page height and width were configured in FopFactory because in XSL:FO page-height=“auto” & page-width=“auto” are defined. I suggest to define page-height & page-width at runtime, for example using an XSLT. The value for page-height & page-width could be read from an input XML document or passed as a parameter during the transformation.

The following is a slightly changed code copied from 
https://github.com/apache/fop/blob/trunk/fop/examples/embedding/java/embedding/ExampleXML2PDF.java <https://github.com/apache/fop/blob/trunk/fop/examples/embedding/java/embedding/ExampleXML2PDF.java>
(a mirror of http://svn.apache.org/viewvc/xmlgraphics/fop/trunk/fop/examples/embedding/java/embedding/ExampleXML2PDF.java?view=markup <http://svn.apache.org/viewvc/xmlgraphics/fop/trunk/fop/examples/embedding/java/embedding/ExampleXML2PDF.java?view=markup> )


    Fop fop = fopFactory.newFop(MimeConstants.MIME_PDF, foUserAgent, out);

    // Setup XSLT
    TransformerFactory factory = TransformerFactory.newInstance();
    Transformer transformer = factory.newTransformer(new StreamSource(xsltfile));

    // Set the value of a <param> in the stylesheet
    transformer.setParameter(“pageHeightParam", “11.00in”);
    transformer.setParameter(“pageWidthParam", “8.5in");


    // Setup input for XSLT transformation
    Source src = new StreamSource(xmlfile);

    // Resulting SAX events (the generated FO) must be piped through to FOP
    Result res = new SAXResult(fop.getDefaultHandler());

    // Start XSLT transformation and FOP processing
    transformer.transform(src, res);


Hope this helps,
Alexios Giotis




> On 23 Apr 2017, at 06:33, Arpit Phanda <ph...@gmail.com> wrote:
> 
> Hi,
> 
> We are migrating our service from apacheFOP-0.95 to apacheFOP-2.1. Our aim is to configure pageHeight and pageLength to singleton instance during each rendering call. 
> 
> In earlier version we could create FopFactory instance by calling FopFactory.newInstance() and then use setPageHeight/setPageWidth on the same instance of FopFactory. Currently, this is no more valid. Now, we are allowed to set these property on FopFactoryBuilder - new FopFactoryBuilder().setPageHeight().build() which means we are creating a new FopFactory instance each time. Is there any way of injecting these property on already created instance.
> 
> PS: Also, i read a few issue where it has been said ApacheFOP is not threadsafe and just wanted to know the reason behind it.
> 
> 
> -- 
> Regards
> Arpit Phanda