Is there better way to do this? (Xml Pretty Print | node removing)

Question

Hi all, I have been working at home on a small project to help my Java Jedi training. :-)
My app saves quotes from authors in an xml file.
I have a class [XmlRepository extends Thread] that holds control of an xml file to handle requests for Nodes.
When I remove a node I get a Line Space above the node that was removed, or better put my node gets replaced by a empty line.
Pretty print or correct Node removing.
part of my xml is like this (I have resumed it for readability):
    <entities forUser="ffffffff-ffff-ffff-ffff-ffffffffffff">
        <quotes/>
        <authors>
            <author id="f156c570-c676-4d69-9b15-ae7d859ff771" languageCode="en" regenerateAs="com.fdt.cognoscere.entities.sources.Author">
                <lastNames>Poe</lastNames>
                <firstNames>Edgar Allan</firstNames>
            </author>
            <author id="35dc0c5a-3813-4a10-af49-8d4ea1c2cee0" languageCode="en" regenerateAs="com.fdt.cognoscere.entities.sources.Author">
                <lastNames>Wilde</lastNames>
                <firstNames>Oscar</firstNames>
            </author>
            <author id="317f72ea-add6-4bd2-8c63-d8b373a830ab" languageCode="en" regenerateAs="com.fdt.cognoscere.entities.sources.Author">
                <lastNames>Christie</lastNames>
                <firstNames>Agatha</firstNames>
            </author>
            <author id="28047c89-b647-4c40-b6c7-677feaf2dfda" languageCode="en" regenerateAs="com.fdt.cognoscere.entities.sources.Author">
                <lastNames>Shakespeare</lastNames>
                <firstNames>William</firstNames>
            </author>
        </authors>
    </entities>If I remove A Node ( Edgar Allan Poe (1st in this case)) the resulting Xml when saved is like this (I have added the space indentation just as it is outputted by my code):
    <entities forUser="ffffffff-ffff-ffff-ffff-ffffffffffff">
        <quotes/>
            <author id="35dc0c5a-3813-4a10-af49-8d4ea1c2cee0" languageCode="en" regenerateAs="com.fdt.cognoscere.entities.sources.Author">
                <lastNames>Wilde</lastNames>
                <firstNames>Oscar</firstNames>
            </author>
            <author id="317f72ea-add6-4bd2-8c63-d8b373a830ab" languageCode="en" regenerateAs="com.fdt.cognoscere.entities.sources.Author">
                <lastNames>Christie</lastNames>
                <firstNames>Agatha</firstNames>
            </author>
            <author id="28047c89-b647-4c40-b6c7-677feaf2dfda" languageCode="en" regenerateAs="com.fdt.cognoscere.entities.sources.Author">
                <lastNames>Shakespeare</lastNames>
                <firstNames>William</firstNames>
            </author>
        </authors>
    </entities>this is how I initialize the XML DOM Handlers, and the method for removing a Node:
     * Initializes factory instances and member variables.
    private void initialize() {
        //obtain an instance of a documentFactory create a document documentBuilder
        this.documentFactory = DocumentBuilderFactory.newInstance();
        //Configure the documentFactory to be name-space aware and validate trough an xsd file
        this.documentFactory.setNamespaceAware(true);
        this.documentFactory.setValidating(true);
        this.documentFactory.setAttribute(JAXP_SCHEMA_LANGUAGE, W3C_XML_SCHEMA);
        try {
            //obtain an instance of an XPathFactory
            this.xpathFactory = XPathFactory.newInstance(XPathFactory.DEFAULT_OBJECT_MODEL_URI);
            //obtain an instance of the xpath evaluator object
            this.xpathEvaluator = this.xpathFactory.newXPath();
            //set namespace mapping configurations
            NamespaceContextMap namespaceMappings = new NamespaceContextMap();
            namespaceMappings.put("xml", "http://www.w3.org/XML/1998/namespace");
            namespaceMappings.put("xmlns", "http://www.w3.org/2000/xmlns/");
            namespaceMappings.put("xsd", "http://www.w3.org/2001/XMLSchema");
            namespaceMappings.put("xsi", "http://www.w3.org/2001/XMLSchema-instance");
            namespaceMappings.put(this.schemaNamespaceMapping, this.schemaNamespace);
            //add mappings
            this.xpathEvaluator.setNamespaceContext(namespaceMappings);
        } catch (XPathFactoryConfigurationException ex) {
            Logger.getLogger(XmlRepository.class.getName()).log(Level.SEVERE, null, ex);
        try {
            //obtain a trasformer factory to save the file
            this.transformerFactory = TransformerFactory.newInstance();
            this.transformerFactory.setAttribute("indent-number", 4);
            //obtain the transforme
            this.transformer = this.transformerFactory.newTransformer();
            //setup transformer
            this.transformer.setOutputProperty(OutputKeys.METHOD, "xml");
            this.transformer.setOutputProperty(OutputKeys.INDENT, "yes");
            this.transformer.setOutputProperty(OutputKeys.MEDIA_TYPE, "text");
            this.transformer.setOutputProperty("{http://xml.apache.org/xslt}indent-amount", "4");
        } catch (TransformerConfigurationException tcex) {
            Logger.getLogger(XmlRepository.class.getName()).log(Level.SEVERE, null, tcex);
     * Removes a node by evaluating the XPATH expression.
     * @param xpath A String instance with the XPATH expression representing the element to remove.
     * @throws com.fdt.cognoscere.storage.exceptions.UnableToRemoveException When an exception occurs that prevents the repository to execute the remove statement.
    public void removeNode(final String xpath) throws UnableToRemoveException {
        Node nodeToRemove = null;
        Node parentNode = null;
        //verify xpath
        if (xpath == null)
            throw new IllegalArgumentException("The xpath argument cannot be null.");
        //verify that the repository is loaded
        if (!this.loaded)
            throw new IllegalStateException("The XmlRepository faild to load properly and it is in an invalid state. It cannot perfom any operation.");
        try {
            //get the node to remove out of the xpath expression
            nodeToRemove = this.getNode(xpath);
            //throw an exception if no node was found to remove
            if (nodeToRemove == null)
                throw new UnableToFindException("The node element trying to be remove does not exist.");
            //obtain the parent node to remove its child
            parentNode = nodeToRemove.getParentNode();
            //remove the node from the parent node
            nodeToRemove = parentNode.removeChild(nodeToRemove);
        } catch.......removed to save space{
        } finally {
            //normalize document
            this.document.normalize();
    }Please tell me if I could do this better,
thanks,
f(t)

Answer 1

franciscodiaztrepat wrote:
When I remove a node I get a Line Space above the node that was removed, or better put my node gets replaced by a empty line.Replaced? No, there's already a new-line character after the node that was removed. And there was one before that node too. You didn't remove either of those, so after the removal there are two consecutive new-line characters. As you can see.
And no, trying to pretty-print the XML document won't remove any of those. It might add whitespace to make the document nicely indented, but it won't ever remove whitespace. If you want whitespace removed then you'll have to do it yourself.
For example, after you remove a node, also remove the node following it if it's a whitespace text node. Or something like that.