XML : How to use the SAX parser to save the only child elements and storing them in the collection?

I have a xml file:

  <shop>      <department number= "1" name="unknown">          <product id="1"/>          <product id="2"/>          <product id="3"/>      </department>      <department number= "2" name="unknown">          <product id="4"/>          <product id="5"/>          <product id="6"/>      </department>      <department number= "3" name="unknown">          <.../>      </department>  </shop>    

To save the data parsing, I created a class Department and a collection ArrayList <Department>, to keep these classes there. The class looks like this:

  class Department {      String number;      String name;      ArrayList<Integer> productId = new ArrayList<>(); // collection for storage "attribut id of product"      //constructor      public Department(String n, String na, ArrayList<Integer> pr) {          this.number = n;          this.name = na;          this.productId = pr;      }  }    

How do I set the SAX-parser to work in each instance of the class Departament got only his daughter tags product id and placed in a particular ArrayList <Integer>?