Class ArrayListIterator

classpath/java/util/Collections.java:462–511

  }

  static class ArrayListIterator<T> implements ListIterator<T> {
    private final List<T> list;
    private int toRemove = -1;
    private int index;

    public ArrayListIterator(List<T> list) {
      this(list, 0);
    }

    public ArrayListIterator(List<T> list, int index) {
      this.list = list;
      this.index = index - 1;
    }

    public boolean hasPrevious() {
      return index >= 0;
    }

    public T previous() {
      if (hasPrevious()) {
        toRemove = index;
        return list.get(index--);
      } else {
        throw new NoSuchElementException();
      }
    }

    public T next() {
      if (hasNext()) {
        toRemove = ++index;
        return list.get(index);
      } else {
        throw new NoSuchElementException();
      }
    }

    public boolean hasNext() {
      return index + 1 < list.size();
    }

    public void remove() {
      if (toRemove != -1) {
        list.remove(toRemove);
        index = toRemove - 1;
        toRemove = -1;
      } else {
        throw new IllegalStateException();
      }
    }
  }

  public static <T> List<T> unmodifiableList(List<T> list)  {
    return new UnmodifiableList<T>(list);