How to iterate through ArrayList of objects?

Question

I have a class called SparseMatrix. It contains an ArrayList of Nodes (also class). I am wondering of how to iterate through the Array and access a value in Node. I have tried the following:

 //Assume that the member variables in SparseMatrix and Node are fully defined.
 class SparseMatrix {
     ArrayList filled_data_ = new ArrayList();
     //Constructor, setter (both work)

     // The problem is that I seem to not be allowed to use the operator[] on
     // this type of array.
     int get (int row, int column) {
         for (int i = 0; i < filled_data_.size(); i++){
             if (row * max_row + column == filled_data[i].getLocation()) {
                 return filled_data[i].getSize();
             }
         }
         return defualt_value_;
     }
 }

I will probably switch to static arrays (and remake it every time I add an object). If anyone has a solution, I would very much appreciate you sharing it with me. Also, thank you in advance for helping me.

Feel free to ask questions if you don't understand anything here.

Answer 1

Assuming filled_data_ is a list that contains list of objects of a class named Node.

List<Nodes> filled_data_ = new ArrayList<>();
for (Node data : filled_data_) {
    data.getVariable1();
    data.getVariable2();
}

More info http://crunchify.com/how-to-iterate-through-java-list-4-way-to-iterate-through-loop/