@JacksonXmlElementWrapper not respected when serializing Iterators / Iterables

[stanislawosinski]

I'm using Jackson 2.5.2 to serialize objects both to JSON and XML. My use case involves serializing large dynamically generated collections, hence the need to expose an Iterator rather than a List for serialization.

Everything works perfectly with one snag: @JacksonXmlElementWrapper does not seem to be respected when serializing Iterator / Iterable. I'd expect the following code:

public class WrapperTest {
  public static void main(String[] args) throws IOException {
    new XmlMapper().writeValue(System.out, new ToSerialize());
  }

  private static class ToSerialize {
    @JsonProperty("item")
    @JacksonXmlElementWrapper(localName = "list")
    public Iterator<String> items() {
      return new Iterator<String>() {
        int item = 4;

        @Override
        public boolean hasNext() {
          return item > 0;
        }

        @Override
        public String next() {
          item--;
          return Integer.toString(item);
        }
      };
    }
  }
}

to produce:

<ToSerialize><list><item>3</item><item>2</item><item>1</item><item>0</item></list></ToSerialize>

but instead I'm getting:

<ToSerialize><item>3</item><item>2</item><item>1</item><item>0</item></ToSerialize>

Am I doing anything wrong here?

If I replace the Iterator with a List, the wrapping element gets correctly added, but switching to in-memory lists is not practical in our use case. I could instead return a dummy list that returns my original iterator in the iterator() method (and throws UnsupportedOperationException in all other methods), but this seems a rather ugly hack.

[cowtowncoder]

I can not reproduce this so it has probably fixed somewhere since 2.5.2.
Marking as fixed in 2.11.0.

[cowtowncoder]

As per @JooHyukKim I think this is actually being only fixed in 2.16 now.