What exactly is this code doing?

Question

Our prof gave us some sample code for converting Person objects into array information, and back again.
My question is about this method:
public Person[] convertToPersonObjects()
  Person p[] = new Person[data.size()];
  for(int i = 0; i < p.length; i++)
     p[i] = new Person((String)((Vector)data.elementAt(i)).elementAt(0),
            (String)((Vector)data.elementAt(i)).elementAt(1),
            (String((Vector)data.elementAt(i)).elementAt(2),
            (String)((Vector)data.elementAt(i)).elementAt(3),
            (String)((Vector)data.elementAt(i)).elementAt(4));
  return p;
}"data" is a vector that has been holding the five attributes of Person. What I'm not getting here is why he used this construction: ((Vector)data.elementAt(i)).elementAt(1)So is this casting the Vector value of the "data" vector element into a String that is then stored as element 1, 2, etc. of the Person object? Why would a vector element have to be cast into a Vector anyway? And I'm confused by the double use of "elementAt".
Help is much appreciated!

Answer 1

((Vector)data.elementAt(i)).elementAt(1)Hi!, I think that your data Vector contains in every posotion another Vector with the elements of each person, so if the position i of Data has a Vector you should cast what elemenAt returns and then acces what you need to create a Person Object.
Search your source code for something like "data.add();" and see if it adds a Vector to data.
The cast to String is done because the elementAt method returns an Object
Hope it helps