How to retrieve reqd. tag values

[Anil Vupputuri]

Hi,
Iam using Xereces.
How to retrieve reqd. tags and their child elements in dynamic way. In the XML given below how to retrieve "Manifest" element and all the child element values in dynamic way. Is there any method with just passing tag name and getting all the child elements and their attribute values in collections(eg., Vector/Hashtable)

<Order>
    <Customer>
<Name>Bill Buckram</Name>
<Cardnum>234 234 234 234</Cardnum>
    </Customer>
    <Manifest>
<Item>
    <ID>209</ID>
    <Title>
Duke: A Biography of the Java Evangelist
    </Title>
    <Quantity>1</Quantity>
    <UnitPrice>$10.75</UnitPrice>
</Item>
<Item>
    <ID>208</ID>
    <Title>
100% Pure: Making Cross Platform Deployment a Reality
    </Title>
    <Quantity>1</Quantity>
    <UnitPrice>$10.75</UnitPrice>
</Item>
<Item>
    <ID>204</ID>
    <Title>
Making the Transition from C++ to the Java(tm) Language
    </Title>
    <Quantity>1</Quantity>
    <UnitPrice>$10.75</UnitPrice>
</Item>
<Item>
    <ID>202</ID>
    <Title>Web Servers for Fun and Profit</Title>
    <Quantity>1</Quantity>
    <UnitPrice>$10.75</UnitPrice>
</Item>
<Item>
    <ID>210</ID>
    <Title>
I Think Not: Dukes Likeness to the Federation Insignia
    </Title>
    <Quantity>1</Quantity>
    <UnitPrice>$10.75</UnitPrice>
</Item>
    </Manifest>
    <Receipt>
<Subtotal>$53.75</Subtotal>
<Tax>$4.43</Tax>
<Total>$58.18</Total>
    </Receipt>
</Order>

Thanks,
Anil

[Anil Vupputuri]

Any ideas???
Thanks,
Anil

[Anonymous]

Hi Anil,
To do this, you can do the following:
1. Load the document into a DOM tree (using JAXP would abstract you from using a SAX or DOM or DOM parser)
2. Locate the manifest node using an XPath expression
3. Traverse the element using the DOM API
Here is some a code extract to do 1 & 2, 3 would depend on what you intend to do with the manifest information.

import org.w3c.dom.*;
import javax.xml.parsers.*;
import org.apache.xpath.XPathAPI;
...
      // Set up the DOM tree
      DocumentBuilderFactory factory = DocumentBuilderFactory.newInstance();
      DocumentBuilder builder = factory.newDocumentBuilder();
      Document doc = builder.parse(filename);
      // Get the Manifest element under the root element
      Node node = XPathAPI.selectSingleNode(doc, "/*/Manifest");
      if (null != node) {
        Element manifest = (Element)node;
        
        // YOUR CODE HERE
        ...

Please tell me if this helps.
Best regards,
Beno�t

[Anil Vupputuri]

Hi Beno�t,
Even i did the same thing to build DOM tree with Xerces as below

import org.w3c.dom.Attr;
import org.w3c.dom.Document;
import org.w3c.dom.Element;
import org.w3c.dom.NamedNodeMap;
import org.w3c.dom.Node;
import org.w3c.dom.NodeList;
.......
         DOMParserWrapper parser =
            (DOMParserWrapper)Class.forName("dom.wrappers.DOMParser").newInstance();
            document = parser.parse(XMLFileName);
            Vector vec = this.getAllElements("manifest")
.....
// **** THE FOLLOWING CODE PRINTS ALL THE VALUES IN SPECIFIC TAG GIVEN ,IF IT FINDS, GIVES U EVERYTHING IN VECTOR 
// **** ABT ALL THE INFORMATION IN THE TAG
// @@@@ BEGIN @@@@@
  
  
  public Vector getAllElements(String str)
  {
      Vector vec = new Vector();
       NodeList elements = document.getElementsByTagName(str);  
       int elementCount = elements.getLength();
      System.out.println("Elem. count "+elementCount);
            for (int i = 0; i < elementCount; i++) {
                Element element = (Element)elements.item(i);
                vec.addElement((Hashtable)getElementTag(element, element.getAttributes()));
            }   
    return vec;
  }
  
   private  Hashtable getElementTag(Element element, NamedNodeMap attributes) {
        Hashtable ht = new Hashtable();
        Hashtable ht1 = new Hashtable();
        System.out.println(" Sub Element Name "+element.getNodeName());
        if (attributes != null) {
            int attributeCount = attributes.getLength();
System.out.println("Attr count " +attributeCount);
            for (int i = 0; i < attributeCount; i++) {
                Attr attribute = (Attr)attributes.item(i);
       System.out.println("Attr Name " +attribute.getNodeName()+" Attr. value "+attribute.getNodeValue());
                ht.put(attribute.getNodeName(),normalize(attribute.getNodeValue()));
            }
        }
        
    ht1.put(element.getNodeName(),ht);
   return ht1;
 }
....

So finally i get the Vector of Hashtables in return.
If i pass "item" in the getAllElements(ElementName) method i will get all the occurances of "item" element in vector and their
corresponding attribute name(as a key in Hashtable) and attribute value( as a value in Hashtable).
My reqt. is to get in a single vector of <item> elements, which has hashtable with element name(as a key) and element value(as a value) and if there are any attributes under this, that should have one more hashtable with attr.name and value.
Does XPath solve this problem.
Or
Can we do it with Xerces alone
How XPath will be useful

Any ideas?

Thanks,
Anil

[Anonymous]

Why would you want to do that? A DOM node already stores all the information you need.
Anyway, you already know how to traverse the DOM tree (as your example shows) and I'm sure you're good enough to come up with the right algorithm for this on your own.
Regards,
Beno�t

[Anil Vupputuri]

I found out JDOM can solve this problem.