Traversing XML data very slow/never ends

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November 9th, 2012, 01:06 PM

Smuck

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Swing - Traversing XML data very slow/never ends

For some reason a command line tool is much quicker at saving data to a file.xml rather than returning data through standard output.

So it's instructed to save a data.xml file which is then parsed to a Document variable in java. And this happens in a few seconds.

But then when traversing the Document to put all data in a String it never finish. This is just meant to test traversing. The string result is not needed.

Code:

    public static String xmlToString(Node xmlDoc) {
        String xmlStr = "\nNode " + xmlDoc.getNodeName() + "\nValue" + xmlDoc.getNodeValue() + "\nText" + xmlDoc.getTextContent() + "\ntoString" + xmlDoc.toString() + "\n";
        
        // Now traverse the rest of the tree in depth-first order.
        if (xmlDoc.hasChildNodes()) {
            // Get the children in a list.
            NodeList nl = xmlDoc.getChildNodes();
            // How many of them?
            int size = nl.getLength();
            for (int i=0; i<size; i++) {
                // Recursively traverse each of the children.
                xmlStr += xmlToString(nl.item(i));
            }
        }
        return xmlStr;
    }

November 9th, 2012, 02:04 PM

Smuck

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Tried altering traverser, but it's still stuck

Code:

    public static String xmlToString(Node xmlDoc) {
        String xmlStr = "\nNode " + xmlDoc.getNodeName() + "\nText:" + xmlDoc.getTextContent() + "\n";
        if (xmlDoc.hasChildNodes()) {
            xmlStr += xmlToString(xmlDoc.getFirstChild());
        }
        if (xmlDoc.getNextSibling() != null) {
            return xmlStr + xmlToString(xmlDoc.getNextSibling());
        }
        return xmlStr;
    }

November 9th, 2012, 02:11 PM

NormR

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Can you make a small, simple program that compiles, executes and shows the problem?

November 10th, 2012, 04:54 AM

Smuck

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Quote:

Originally Posted by NormR

Can you make a small, simple program that compiles, executes and shows the problem?

The code is broken up in different files (Netbeans - latest version).

I'm trying to use the command line tool MP4Box to get information about a media file. With -diso it dumps the file structure in .xml . With -std -diso it returns the data but it takes much longer.

So this code retrieves xml from file and it takes a few secs:

Code:

    public String MP4BoxSend(String arg) {
        Runtime rt = Runtime.getRuntime();
        String line, output = "";
        try {
            Process pr = rt.exec("mp4box\\MP4Box.exe " + arg);
            BufferedReader input = new BufferedReader(new InputStreamReader(pr.getInputStream()));
            while ((line = input.readLine()) != null) {
                output += "\n" + line;
            }
            int exitVal = pr.waitFor();
        } catch(IOException | InterruptedException e) { 
            JOptionPane.showMessageDialog(null, e.toString(), "Error", JOptionPane.ERROR_MESSAGE);
        }
        return output;
    }

    Document MediaXml;
    
    public String MP4BoxGetMediaInfo(String file_name) {
        String arg = "-diso \"" + file_name + "\""; // Dump Media Info in XML file
        String Error = MP4BoxSend(arg);

        String XmlFilename = ExtendedString.removeExt(file_name) + "_info.xml";
        File file = new File(XmlFilename); // Connect to dumped xml file
        if (file.exists()) {
            DocumentBuilderFactory dbf = DocumentBuilderFactory.newInstance();
            DocumentBuilder db;
            try {
                db = dbf.newDocumentBuilder();
                MediaXml = db.parse(file);
            } catch (ParserConfigurationException | SAXException | IOException ex) {
                Logger.getLogger(MP4Box.class.getName()).log(Level.SEVERE, null, ex);
            }
            file.delete();
        }
        return Error;
    }

And this code calls method that is supposed to traverse xml and output it in string just so I can see traversing works:

Code:

            MP4Box mb = new MP4Box();
            String MP4BoxError = mb.MP4BoxGetMediaInfo(file_name);
            jTextAreaSource.append("\nXML file parsed! " + MP4BoxError + "\nWill now print out: ");
            jTextAreaSource.append("\n" + ExtendedString.xmlToString(mb.MediaXml));

November 10th, 2012, 07:06 AM

NormR

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Location: SW Missouri

Posts: 2,958

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How do I compile and test the code to see the problem? You haven't posted all the code needed for testing.

Swing - Traversing XML data very slow/never ends

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