DOM API don't undestand

[jazy smith]

Hi all,

I have a piece of simple xml document.

  
<student>
	<name>abc</name>
	<rollno>123</rollno>
	<address>
		<USAddress>111</USAddress>
		<IndAddress>222</IndAddress>
	</address>
</student>  

Now I have JAX API

DocumentBuilderFactory dbf =  DocumentBuilderFactory.newInstance();        	
        	DocumentBuilder builder = dbf.newDocumentBuilder();        	
        	Document doc = builder.parse(new File("C://test.xml"));        	
        	
        	NodeList section = doc.getElementsByTagName("student");
        	System.out.println(section.getLength());   

the result it returns is 1. I don't understand why. How does it calculate the length ?

next question, for the same xml file,

Document doc = builder.parse(new File("C://test.xml"));        	
        	
        	NodeList section = doc.getElementsByTagName("student");

        	Node node = section.item(0);
        	
        	NodeList nl = node.getChildNodes();
        	
        	System.out.println(nl.getLength());    

the result is 7. How come ? I was thinking the child elements of "student" is 3 (name, rollno, address) it should return 3. how come it returned 7.
please explain me as I have been trying to draw the schematic diagram and tried my best to undestand but couldn't get through...
thanks

[Paul Clapham]

You're asking how it calculates the "length" of a NodeList? That would be the number of the elements in the NodeList.

In your example you found a NodeList containing all of the <student> elements in your document. There's only one such element. Therefore the NodeList contains just one element. So it shouldn't be a surprise that the "length" of the NodeList is one.

As for the child nodes of that one <student> element, they are:

A whitespace text node

A <name> element

A whitespace text node

A <rollno> element

A whitespace text node

An <address> element

A whitespace text node

You'll find that's 7 children.

[jazy smith]

thanks a lot Paul