Making constructor for XML in Processing, Java

[mamacach]

I am trying to visualize data from an Open Data web page. The data is parsed from an XML-file with geo coordinates (latitude and longitude).

I am trying to make this XML-reader universal through OOP, so that I can use it for other purposes for another time. At the moment the XML-reader works, but I am having a bit of a hard time appropriating classes and objects in the reader. In my case I want to make one function that splits the lat/long coordinates and converts them to pixels. Then I also want a function that draws a polygon where the specific coordinates are.

But before making an XML-reader class I have to know what constructor my XML-reader is going to have.

So my question: Is there a standard (and maybe also a simple) way to do this in Java?

My code looks like this:

XML xml; 
ArrayList coordinates; 

void setup() {

  coordinates=new ArrayList(); 

  xml = loadXML("parkerudenbom.xml");

  XML[] folder = xml.getChildren("Folder");

  XML[] Placemark=folder[0].getChildren("Placemark"); 

  println(Placemark.length);

  for(int i = 0; i < Placemark.length; i++) {
    XML[] Polygon=Placemark[i].getChildren("Polygon"); 
    for(int j= 0; j < Polygon.length; j++) {  

      XML[] outerBoundaryIs=Polygon[j].getChildren("outerBoundaryIs"); 
      XML[] LinearRing=outerBoundaryIs[0].getChildren("LinearRing"); 
      XML[] coords = LinearRing[0].getChildren("coordinates"); 

      coordinates.add(coords[0].getContent()); 

      println(coords[0].getContent()); 
    }

  }

}

The xml file is this one: https://www.dropbox.com/s/3p7l2mqr7fcjjrn/parkerudenbom.x ml

[chaarmann]

You can use Xpath to get your list of coordinates much more comfortable and with less code.
Like

NodeList nodeList = (NodeList) xPath.compile(expression).evaluate(xmlDocument, XPathConstants.NODESET);

Just replace "expression " with the value "/Folder/Placemark", then loop through the nodeList with a foreach loop and do it again inside loop using expression "Polygon/outerBoundaryIs/LinearRing/coordinates". Or use "Polygon/outerBoundaryIs/LinearRing/coordinates/coordinates[1]" to select the first coordinate if there are more than one.