Processing sketch : stackIterator

main.pde

Stack<String> stack;


void draw(){
   background(0);
   text(stack.pop(), width/2, height/2  );
   stack.push(mouseX + ", " + mouseY);
   
}

setup.pde

int CW = 800;   
int CH = 600;
void setup(){
   size(CW, CH);
   stack = new Stack();
   stack.push("Hello");
}

stackIterator.pde

//#GIST:7449487

import java.util.Iterator;
class Stack<Item> 
implements Iterable<Item>
{
  
    Node<Item> current;  
  
  
  
    
    Iterator<Item> iterator(){
       return new StackIterator<Item>();
//      return null;
    }
  
  
    boolean isEmpty(){
        return ( current == null);
    }
  
  
    void push(Item it){
        Node<Item> n = new Node<Item>(current, it);
        current = n;
    }
    
    
    Item pop(){
        if ( current == null){
           throw new RuntimeException("Can't pop, stack is null");
        }
        Item res = current.item;
        current = current.next;
        return res;       
    }

    
  class StackIterator<Item1> implements Iterator<Item1>
  {
      boolean hasNext(){
         throw new RuntimeException("un");
      }
      
      Item1 next(){
        throw new RuntimeException("un");
      }
      
      void remove(){
        throw new RuntimeException("un");
      }
      
  }    
    
}



class Node<Item>
{
  
    Node next;
    Item item;
  
    Node(Node node, Item it){
       next = node;
       item = it;
    }
}