How to initialize custom iterator?

Question

The program I am trying to make consists of creating a class named Matrix that is iterated with two custom iterators, rowColumIterator and columRowIterator . The problem is that, when initializing the iterator, in the Matrix class, the following error occurs:

Cannot resolve method 'iterator()'

I do not know if the problem is in how I am creating the iterator or inside the Matrix class.

The iterator code is:

public class rowColumnIterator<T> implements Iterator<T> {

    private T[][] dataset;
    private int rowIndex;
    private int columnIndex;

    public rowColumnIterator(T[][] dataset) {
        this.dataset = dataset;
    }

    @Override
    public boolean hasNext() {
        if (rowIndex >= dataset.length)
            return false;
        if (columnIndex >= dataset[rowIndex].length &&
                (rowIndex >= dataset.length || rowIndex == dataset.length - 1))
            return false;
        return true;
    }

    @Override
    public T next() {
        if (!hasNext())
            throw new NoSuchElementException();
        if (columnIndex >= dataset[rowIndex].length) {
            rowIndex++;
            columnIndex = 0;
        }
        return dataset[rowIndex][columnIndex++];
    }

    @Override
    public void remove() {
        throw new UnsupportedOperationException("Not yet implemented");
    }

}

Inside the matrix class I have this inside the constructor:

    this.matrix = new int[rows][columns];
    rowColumnIterator<Integer> iterator = this.matrix.iterator();

I would appreciate if you could tell my what I am doing wrong.

Answer 1

You have to instantiate the iterator with its constructor:

rowColumnIterator<Integer> iterator = new rowColumnIterator<>(this.matrix);