Detecting a PDF Package or Portfolio in code

Does anyone know of a way to detect whether a given PDF file is a PDF Portfolio or a PDF Package, rather than a "regular" PDF? I'd prefer Java solutions, although since I haven't yet found any information on detecting the specific type of PDF, I'll take what I can get and they try to figure out the Java solution afterwards.

(In searching past questions, it appears that a bunch of folks don't know that such things as PDF Portfolios and PDF Packages exist. Generally, they're both ways that Adobe allows multiple, discrete PDFs to be packaged into a single PDF file. Opening a PDF Package in Reader shows the user a list of the embedded PDFs and allows further viewing from there. PDF Portfolios appear to be a bit more complicated -- they also include Flash-based browser for the embedded files, and then allow users to extract the discrete PDFs from there. My issue with them, and the reason I'd like to be able to detect them in code, is because OS X's built-in Preview.app can't rea开发者_如何学运维d these files -- so I'd like to at least warn users of a web app of mine that uploading them can lead to diminished compatibility across platforms.)

This question is old, but in-case someone wants to know, it is possible. It can be done with Acrobat and JavaScript by using the following command.

 if (Doc.collection() != null)
 {
     //It Is Portfolio
 }

Acrobat JavaScript API says, "A collection object is obtained from the Doc.collection property. Doc.collection returns a null value when there is no PDF collection (also called PDF package and PDF portfolio).The collection object is used to set the initial document in the collection, set the initial view of the collection, and to get, add, and remove collection fields (or categories)."

I'm also facing same problem while extracting data through kofax,  but i got solution and its working fine need to add extra jar for Document class.

import java.io.File;
import java.io.IOException;
import java.io.InputStream;

public class PDFPortfolio {

    /**
     * @param args
     */
    public static void main(String[] args) {

        com.aspose.pdf.Document pdfDocument = new com.aspose.pdf.Document("e:/pqr1.pdf");
        // get collection of embedded files
        com.aspose.pdf.EmbeddedFileCollection embeddedFiles = pdfDocument.getEmbeddedFiles();
        // iterate through individual file of Portfolio
        for(int counter=1; counter<=pdfDocument.getEmbeddedFiles().size();counter++)
        {
            com.aspose.pdf.FileSpecification fileSpecification = embeddedFiles.get_Item(counter);
            try {
                InputStream input = fileSpecification.getContents();
                File file = new File(fileSpecification.getName());
                // create path for file from pdf
              //  file.getParentFile().mkdirs();
                // create and extract file from pdf
                java.io.FileOutputStream output = new java.io.FileOutputStream("e:/"+fileSpecification.getName(), true);
                byte[] buffer = new byte[4096];
                int n = 0;
                while (-1 != (n = input.read(buffer)))
                output.write(buffer, 0, n);

                // close InputStream object
                input.close();
                output.close();
                } catch (IOException e) {
                e.printStackTrace();
            }
        }

    }

}