need advice on Element and Node

[Norazanita Adnan]

hi..
is there anything wrong with this code?

 
 
try {
 
 DocumentBuilder builder = dbf.newDocumentBuilder();
 doc = builder.parse(new InputSource(new StringReader(name)));
 doc.getDocumentElement ().normalize ();  
 Element root = doc.getDocumentElement ();
//it send the element root to the function
 traverse (root);
 
 }catch (Exception t) {
...
 

public static void traverse( Node currNode ) {
 
 NodeList nodes = currNode.getChildNodes();
 for( int i=0 ; i<nodes.getLength(); i++ ){
    n = nodes.item( i );
 
    if( n.getNodeType() == Node.ELEMENT_NODE ){
    currNode = nodes.item(i);
    traverse( n );
 }//end of if
    valueNode = n.getNodeValue().toString();
 }//end of for
Node newName = currNode.getParentNode();
Node newName2 = currNode;
 
System.out.println ( newName + newName2 + valueNode);
 
}
 
   

im confuse here

Element root = doc.getDocumentElement ();  

--> is a Element
but i the function can receive in as an element, i need receive as an node type.

public static void traverse( Node currNode ) {   

can i declare

Node root = doc.getDocumentElement ();  

I know element is the subinterface of node but i dont get get what is the diff when i declare "Element root" instated of "Node root"

Hope someone able to advice me on this.

thanks in advance.

[Paul Clapham]

It's just basic polymorphism. An Element "IS A" Node, because Element is a subinterface of Node. That means that Element has all the methods that Node does. It also means that Element could have some other methods that Node doesn't have, and in fact it does. It has methods allowing you to access the attributes of the element. Those methods aren't in the Node interface because not all types of nodes have attributes.

[Norazanita Adnan]

thanks..so meaning now it find i declare as Element and send as and Node type..thanks..no i start to like programming....