public boolean matches(Object item) {
if (expected == item) return true;
if (item == null) return false;
if (expected.getClass() != item.getClass()) return false;
Item other = (Item) item;
return expected.index().equals(other.index())
&& expected.type().equals(other.type())
&& expected.id().equals(other.id())
&& Arrays.equals(expected.fields(), other.fields());
}