How to parse a generic XML file in J2ME with kXML

Some days ago I’ve posted J2ME code to parse RSS feeds using kXML library. Today’s code is about parsing a generic XML, so you can use it to parse any XML document you want. Code is splitted in the following two classes.

XmlNode class

This is the class representing a single node. We’ll define 2 node types:

  • Text nodes: nodes without a name, contanining only a textual value. For them we’ll define a TEXT_NODE final variable
  • Element nodes: nodes with a tag name, that can have children nodes and/or attributes

XmlNode class source code is available here: XmlNode.java

GenericXmlParser class

This is the class that will actually do XML parsing. We’ll define only one public method, parseXML(), that will accept 2 arguments:

  • a KXmlParser instance, that will be used to do XML parsing
  • a boolean that will tell if whitespace-only text nodes must be ignored or not

and will return and XmlNode representing the root node of the parsed XML tree.

GenericXmlParser class source code is available here: GenericXmlParser.java

Sample usage

Let’s see how we can use the two classes above. First we must instantiate and initialize a KXmlParser, and then we can call our GenericXmlParser parseXML() method.

InputStreamReader reader = new InputStreamReader(getClass().getResourceAsStream("/test3.xml"));
 
KXmlParser parser = new KXmlParser();
 
parser.setInput(reader);
 
GenericXmlParser gParser = new GenericXmlParser();
 
XmlNode xml = gParser.parseXML(parser, true);

Now, we have our resulting XmlNode that will hold the whole XML tree. We can make a simple dump of it to check if it’s all ok, using this test function:

void dumpXML(XmlNode node, int deep)
{
	for(int i = 0; i < deep; i++)
	{
		System.out.print(" ");
	}
	System.out.print(node.nodeName + " - ");
 
	if(node.nodeValue != null)
	{
		System.out.print("(" + node.nodeValue + ") - ");
	}
	String[] attributes = node.getAttributeNames();
 
	for(int i = 0; i < attributes.length; i++)
	{
		System.out.print(attributes[i] + ": " + node.getAttribute(attributes[i]) + ", ");
	}
 
	System.out.println();
 
	for(int i = 0; i < node.children.size(); i++)
	{
		dumpXML((XmlNode)node.children.elementAt(i), deep + 1);
	}
}

Note: This article is available also on Forum Nokia Wiki: How to parse an XML file in J2ME with kXML

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