Question

i want to get the maximum depth of an XML file using a recursive method firstly i have declared the variable

 public static int maxdepth=0;

 private static void GetDepth(NodeList nl, int level,int maxdepth) {      

   level++;
   if (maxdepth<level)
   {
       maxdepth= level;
   }
    if(nl != null && nl.getLength() > 0){
        for (int i = 0; i < nl.getLength(); i++) {
            Node n = nl.item(i);
            if (n instanceof Element)
            {            
            GetDepth(n.getChildNodes(), level, maxdepth);
            }
        }

    }

}

 public static void main(String[] args) {
  NodeList nl = root.getChildNodes();
  GetDepth(nl,level,maxdepth);
  System.out.println(maxdepth);
 }

and when i would display the value of variable maxdepth, I receive the value 0, as the declaration

Answer 1

You can do it as a one-liner using XPath 2.0:

max(for $n in //* return count($n/ancestor::*))

Even in Java, you’re making it much more difficult than it is:

public int maxDepth(Node node) {
  int max = 0;
  NodeList kids = node.getChildNodes();
  if (kids.getLength() == 0) {
     return 0;
  }
  for (int i=0; i<kids.getLength(); i++) {
     int kidMax = maxDepth(kids.item(i);
     if (kidMax > max) max = kidMax;
  }
  return max + 1;
}

Not tested.