Sample Code For DOM

[Raghuraman Muthuswamy]

Hello All,
I just need a simple DOM Parser Code just to kick start my understanding of DOM Parsing using Java. Your help is very much appreciated.

Thanks in advance,
Raghu

[Balaji Loganathan]

Go to IBM developers website, then click XML, then xml tutorials or articles, there you will find bunches of article/tutorials on xml, dom, sax, xslt,fop,databinging etc., Try to find the tutorial "Understaning DOM" in it.
Regards
Balaji

[Bajji Pat]

Hi Raghu,

Pls find the code below (just covering the basic requirements)

//IMPORT THE FOLLOWING
 
import java.io.ByteArrayInputStream;
 
import javax.xml.parsers.DocumentBuilder;
import javax.xml.parsers.DocumentBuilderFactory;
 
import org.w3c.dom.Document;
import org.w3c.dom.NamedNodeMap;
import org.w3c.dom.Node;
 
//IMPORT ENDS
 
public void traverse(Node node) {
// Some sample things you might expect from a parser
// i.e storing value of node based on node name
// say when you get tag "Error" you might to know the reason or value of tag
 
do {
    if(TEXT_NODE.equals(node.getNodeName()) )
    {
    // i.e if your node name is the one you expect then 
    // store the value in some string
    NODE_VALUE=node.getNodeValue();
    }
    
    if(TEXT_NODE.equals(node.getFirstChild().getNodeName()))
    {
// i.e the first sibling's value 
// ex. <parent><child>Some Name</child></parent>
// Then node.getFirstChild() would give <child> and 
// that.getNodeValue() would return "Some Name"


PRESENCE_STATUS = node.getFirstChild().getNodeValue();
     }


    if(NODE_NAME.equals(node.getNodeName()))
    {
// Here we get the attributes for a particular node
// like <parent childCount="2"> here "childCount"
// is the attribute and "2" is the value for attribute

int attrLen=0;
NamedNodeMap attrList = node.getAttributes();
 if (attrList != null) {
   attrLen = attrList.getLength();
   } 
   for (int i = 0; i < attrLen; i++) {
   Node attrNode = attrList.item(i);
   if(ATTRIBUTE_NAME.equals(attrNode.getNodeName()))
   {
      //System.out.println("Node!!!!! name: " +attrNode.getNodeName());
      //System.out.println("Node!!!!! Value: " +attrNode.getNodeValue());
     
     if(ATTRIBUTE_VALUE.equals(attrNode.getNodeValue()))
     {
// SOME action based on condition
     }
    
   }
   }
    }
   
  // Recursively calling the function to parse the complete DOM 
 
    if (node.getFirstChild() != null) {
        traverse(node.getFirstChild());
    }
   } while ((node = node.getNextSibling()) != null);
}




/**
 * @param xml - The String XML which is to be parsed
 * @throws Exception - Exceptions arising out of node traversal
 */
public void parseXML(String xml) throws Exception
//String Arguement--Change to InputStream if Required 
{
byte bytearray[] = xml.getBytes();
ByteArrayInputStream bais = new ByteArrayInputStream(bytearray);
DocumentBuilderFactory factory = DocumentBuilderFactory.newInstance();
factory.setValidating(false);
DocumentBuilder builder = factory.newDocumentBuilder();
Document document = builder.parse(bais);
traverse(document);
}
 

Hope this is useful.

Regards
Bajji Pat

Edit Comment:
Added the [ code ] and [ / code ] tags without he spaces.

- m
[ April 12, 2005: Message edited by: Madhav Lakkapragada ]

[Raghuraman Muthuswamy]

Hi Balaji and Bajji,
Thanks for your reply. Both of your replies are useful to me. Can you explain me about Namespaces in XML its a bit confusing to me. If you explain me about namespace in simple terms it will be useful.

With regards,
Raghu