Not always you have an XML file to load, so we need a method to create new instance of a Document object. In order to do that we’ll use DocumentBuilder to create a new instance.

/**
* Creates a new XML document and returns it.
* @return a new XML document without any data
* @exception XMLException if an error occurred creating the new XML document
*/
public static Document newDocument() throws XMLException
{
   try
   {
     DocumentBuilderFactory factory;
     DocumentBuilder builder;
     factory = DocumentBuilderFactory.newInstance();
     factory.setNamespaceAware(false);
     factory.setValidating(false);
     builder = factory.newDocumentBuilder();
     return builder.newDocument();
   }
   catch (ParserConfigurationException e)
   {
     throw new XMLException("Error creating new document.", e);
   }
}


Now that we have the Document we’ll write some methods to manipulate the Document Nodes. The method names are pretty much self explanatory.


/**
* Creates a child element with a text value
* @param parent The parent element
* @param name The child's name (tag)
* @param textValue The text that goes in the child's element
* @return The newly created element
* @throws XMLException
*/
public static Element createChildElementWithText(Element parent, String name, String textValue)
throws XMLException
{
   Element child = parent.getOwnerDocument().createElement(name);
   parent.appendChild(child);
   setTextForNode(child, textValue);
   return child;
}

setTextForNode will be used to set a text for a node. In this method we’ll check first if the node we want to update already contains text. If it is then we’ll update the text value with the new value. If no text node exists then we’ll create a new text node as a child node of the current node.


/**
* Updates the text for the given node.
* @param node the node to update
* @param newValue the value to be place at that node
* @exception XMLException if an error occurred updating the XML Node
*/
public static void setTextForNode(Node node, String newValue) throws XMLException
{
   NodeList children;
   Node childNode;
   children = node.getChildNodes();
   boolean success = false;
   if (children != null)
   {
     for (int i = 0; i < children.getLength(); i++)
     {
       childNode = children.item(i);
       if ((childNode.getNodeType() == org.w3c.dom.Node.TEXT_NODE) || (childNode.getNodeType() == Node.CDATA_SECTION_NODE))
       {
         childNode.setNodeValue(newValue);
         success = true;
       }
     }
   }
   if (!success)
   {
     Text textNode = node.getOwnerDocument().createTextNode(newValue);
     node.appendChild(textNode);
   }
}


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