Modifying a Document

• With DOM we can change the Document in any way we want.

public class OrderProcessor {

  /** Change the value of node elemName to elemValue */
  private static void changeOrder (Node start, 
                                   String elemName, 
                                   String elemValue)
  {
    if (start.getNodeName().equals(elemName)) {
      start.getFirstChild().setNodeValue(elemValue);
    }
         
    for (Node child = start.getFirstChild(); 
         child != null;
         child = child.getNextSibling())
    {
      changeOrder(child, elemName, elemValue);
    }
  }

  public static void main (String args[]) {
        
    // Change text value of node named status to processing.
    changeOrder(root, "status", "processing");

    //Get a list of nodes that have a status element.
    NodeList orders = root.getElementsByTagName("status");

    for (int orderNum = 0; 
         orderNum < orders.getLength(); 
         orderNum++) 
    {
      System.out.println(orders.item(groupNum).getFirstChild().getNodeValue());

      Element thisOrder = (Element)orders.item(orderNum);

      //Remove the limit attribute from customer.
      Element customer = (Element)thisOrder.getElementsByTagName("cusomertid").item(0);
      customer.removeAttribute("limit");  
      
      NodeList orderItems = thisOrder.getElementsByTagName("item");
      double total = 0;
      for (int itemNum = 0;
           itemNum < orderItems.getLength();
           itemNum++) {
      
        // Total up cost for each item and 
        // add to the order total
        
        //Get this item as an Element
        Element thisOrderItem = (Element)orderItems.item(itemNum);

        //Remove a node.
        //Remove anything with <item instock="N">
        if (thisOrderItem.getAttributeNode("instock").getNodeValue().equals("N")) {
          Node deadNode = thisOrderItem.getParentNode().removeChild(thisOrderItem);

          continue;

          //Alternatively, we could have replaced this item with a backorderd element.
          // <item itemid="123">
          //   <backordered></backordered>
          // </item>
          Element backElement = doc.createElement("backordered");

          //<backordered itemid="">
          backElement.setAttributeNode(doc.createAttribute("itemid"));

          //<backordered itemid="123">
          String itemIdString = thisOrderItem.getAttributeNode("itemid").getNodeValue();
          backElement.setAttribute("itemid", itemIdString);

          Node deadNode = thisOrderItem.getParentNode()
            .replaceChild(backElement, thisOrderItem);
        } 

        //Get pricing information for this Item
        String thisPrice = thisOrderItem.getElementsByTagName("price").item(0)
          .getFirstChild().getNodeValue();
        double thisPriceDbl = new Double(thisPrice).doubleValue();
        
        //Get quantity information for this Item
        String thisQty = thisOrderItem.getElementsByTagName("qty").item(0)
          .getFirstChild().getNodeValue();
        double thisQtyDbl = new Double(thisQty).doubleValue();

        double thisItemTotal = thisPriceDbl*thisQtyDbl;
        total = total + thisItemTotal;
      }
      String totalString = new Double(total).toString();

      //1234.34
      Node totalNode = doc.createTextNode(totalString);

      //<total></total>
      Element totalElement = doc.createElement("total");

      //<total>1234.34</total>
      totalElement.appendChild(totalNode);

      //Add that element before anyone else.
      thisOrder.insertBefore(totalElement, thisOrder.getFirstChild());

    }
  }
}