java 迭代器

public class ReversibleArrayList<T> extends ArrayList<T> {

	public ReversibleArrayList(Collection<T> c) {
		super(c);
	}
	
	public Iterable<T> reversed() {
		return new Iterable<T>() {
			@Override
			public Iterator<T> iterator() {
				return new Iterator<T>() {
					int current = size() -1;
					@Override
					public boolean hasNext() {
						return current > 0;
					}
					@Override
					public T next() {
						return get(current--);
					}
					@Override
					public void remove() {
						throw new UnsupportedOperationException("unsupported");
					}
				};
			}
		};
	}
}