package com.wrox.algorithms.iteration;/** * An {@link Iterator} where {@link #isDone()} always returns <code>true</code>. * */public final class EmptyIterator implements Iterator {    /** The single, publicly accessible, instance of the comparator. */    public static final EmptyIterator INSTANCE = new EmptyIterator();    /**     * Constructor marked private to prevent instantiation.     */    private EmptyIterator() {        // Nothing to do    }    public void first() {        // Nothing to do    }    public void last() {        // Nothing to do    }    public boolean isDone() {        // We're always done!        return true;    }    public void next() {        // Nothing to do    }    public void previous() {        // Nothing to do    }    public Object current() throws IteratorOutOfBoundsException {        throw new IteratorOutOfBoundsException();    }}