ArrayIterator.java

import java.util.ArrayList;
import java.util.Iterator;
import java.util.List;
import java.util.NoSuchElementException;

public class ArrayIterator implements Iterator<T> {
    
    // Set local variables
    private T[][] array2D;
    private int pos = 0; // The position of our cursor
    private List list;// What we are going to return
    private int maxIterations;
    private boolean shouldRemove;
    private final int firstIndex = 0;
    
    // The default constructor
    public ArrayIterator(T[][] array2D) {
        this.array2D = array2D;
        this.shouldRemove = false;
        copyArray(Array2D);
    }
    
    /**
     * Move through array
     */
    @Override
    public boolean hasNext() {
        return pos < maxIterations; // Start at 0 and move up
    }
   
   /**
    * When called will print all the values in the 2D
    * Array
    */
    @Override
    public Integer next() throws NoSuchElementException {
        
        if (!hasNext()) {
            throw new NoSuchElementException();
        }
        
        // Get value then remove it from the list
        Integer result = (Integer) list.get(firstIndex);
        pos++;
        shouldRemove = true;
        remove();
        return result;
    }
    
    // Set max iterations
    public void setMaxIterations(List list) {
        if(list != null) {
            maxIterations = list.size();
        }
    }
    
    // Copy values into the collection while skipping over null values
    // with a nested for-loop
    private void copyArray(T[][] array) {
        list = new ArrayList<T>();
        
        // Loop though all values
        for (T[] data : array) {
            for (int val : data) {
                list.add(val);
            }
        }
        
        // Set total number of iterations
        setMaxIterations(getList());
    }
    
    // Remove previous element returned by iterator
    public void remove() {
        if(shouldRemove) {
            list.remove(firstIndex);
            shouldRemove = false;
        }
    }
    
    // Return the list
    public List getList() {
        return this.list;
    }
    
    // Test the code
    public static void main(String[] args) {
        
        int[][] array2D = { {1, 2}, {3}, {} , {5, 6}, {}, {7, 8, 9, 10} };

        ArrayIterator<Integer> ai = new ArrayIterator<Integer>(array2D);
        
        while(ai.hasNext()) {
            System.out.println(ai.next());
        }
        
        System.out.println(ai.getList());
        
    }
}