Getting JSON from Jersey with circular dependencies

Question

Hi

I am writing a service that uses Jersey and JAXB. My classes are annotated with @XMLRootElement, @XMLElement, etc. I have a circular dependency between two classes, so I have annotated the circular dependent property with @XMLTransient. So when I call my service I get xml as the default, which works perfectly. However, when I try using JSON, I get repeated lines like:

{"name":"dere","entries":[{"points":0,"wins":0,"losses":0,"ties":0,"leaderboard":{"name":"dere","entries":[{"points":0,"wins":0,"losses":0,"ties":0,"leaderboard":{"name":"dere","entries":[{"points":0,"wins":0,"losses":0,"ties":0,"leaderboard":{"name":"dere","entries":[{"points":0,"wins":0,"losses":0,"ties":0,"leaderboard":{"name":"dere"," ... etc.

So it seems there is a problem with circular dependencies when I am using JSON. I would like to avoid the circular dependent item from showing up in the JSON output, like it is done in XML (because of the @XMLTransient annotation).

Can anyone provide any insight on how I would be able to achieve this?

Thanks.

Answer 1

It's probably worth checking out Kris Zyp's JSON Referencing proposal. It was invented specifically to handle multiple references and circular references in JSON data.

(Note: Despite the article title, Dojo isn't required. The original proposal was on json.com, but that site is inaccessible to me at the moment.)

How you would implement this technique in Jersey is, unfortunately, an exercise left to the reader.

Answer 2

Use @JsonIgnore instead of @XmlTransient to break the circular dependency.

I had a similar problem as you and this did the trick for me.