class PDXFAResource implements COSObjectable
{
    
    private final COSBase xfa;

    /**
     * Constructor.
     *
     * @param xfaBase The xfa resource.
     */
    public PDXFAResource(COSBase xfaBase)
    {
        xfa = xfaBase;
    }

    /**
     * {@inheritDoc}
     */
    @Override
    public COSBase getCOSObject()
    {
        return xfa;
    }
    
    
    /**
     * Get the XFA content as byte array.
     * 
     * The XFA is either a stream containing the entire XFA resource or an array specifying individual packets that
     * together make up the XFA resource.
     * 
     * A packet is a pair of a string and stream. The string contains the name of the XML element and the stream
     * contains the complete text of this XML element. Each packet represents a complete XML element, with the exception
     * of the first and last packet, which specify begin and end tags for the xdp:xdp element. [IS0 32000-1:2008:
     * 12.7.8]
     * 
     * @return the XFA content
     * @throws IOException if the XFA content could not be created
     */    
    public byte[] getBytes() throws IOException 
    {
        // handle the case if the XFA is split into individual parts
        if (this.getCOSObject() instanceof COSArray) 
        {
            return getBytesFromPacket((COSArray) this.getCOSObject());
        }
        else if (xfa.getCOSObject() instanceof COSStream) 
        {
            return getBytesFromStream((COSStream) this.getCOSObject());
        }
        return new byte[0];
    }
    
    /*
     * Read all bytes from a packet
     */
    private static byte[] getBytesFromPacket(final COSArray cosArray) throws IOException
    {<FILL_FUNCTION_BODY>}
    
    /*
     * Read all bytes from a COSStream
     */
    private static byte[] getBytesFromStream(final COSStream stream) throws IOException
    {
        try (final InputStream is = stream.createInputStream())
        {
            return is.readAllBytes();
        }
    }
    
    /**
     * Get the XFA content as W3C document.
     * 
     * @see #getBytes()
     * 
     * @return the XFA content
     * 
     * @throws IOException if something went wrong when reading the XFA content.
     * 
     */        
    public Document getDocument() throws IOException
    {
        return org.apache.pdfbox.util.XMLUtil //
                .parse(new ByteArrayInputStream(this.getBytes()), true);
    }
}

        try (final ByteArrayOutputStream baos = new ByteArrayOutputStream())
        {
            for (int i = 1; i < cosArray.size(); i += 2) 
            {
                COSBase cosObj = cosArray.getObject(i);
                if (cosObj instanceof COSStream) 
                {
                    baos.write(getBytesFromStream((COSStream) cosObj.getCOSObject()));
                }
            }
            return baos.toByteArray();
        }
    
<no_super_class>