Jackson deserialization of type with different objects

Question

I have a result from a web service that returns either a boolean value or a singleton map, e.g.

Boolean result:

{
    id: 24428,
    rated: false
}
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Answer 1

No no no. You do NOT have to write a custom deserializer. Just use "untyped" mapping first:

public class Response {
  public long id;
  public Object rated;
}
// OR
public class Response {
  public long id;
  public JsonNode rated;
}
Response r = mapper.readValue(source, Response.class);

which gives value of Boolean or java.util.Map for "rated" (with first approach); or a JsonNode in second case.

From that, you can either access data as is, or, perhaps more interestingly, convert to actual value:

if (r.rated instanced Boolean) {
    // handle that
} else {
    ActualRated actual = mapper.convertValue(r.rated, ActualRated.class);
}
// or, if you used JsonNode, use "mapper.treeToValue(ActualRated.class)

There are other kinds of approaches too -- using creator "ActualRated(boolean)", to let instance constructed either from POJO, or from scalar. But I think above should work.