Question

is it possible to deserialize enums, which have a one based index?

enum Status {
  Active,
  Inactive
}

{status:1} means Status.Active, but Jackson makes it Status.Inactive 🙁

Answer 1

You can create a custom type deserialiser for your enum:

public enum Status {
    ACTIVE,
    INACTIVE;
    public static Status fromTypeCode(final int typeCode) {
        switch(typeCode) {
        case 1: return ACTIVE;
        case 2: return INACTIVE;
        }
        throw new IllegalArgumentException("Invalid Status type code: " + typeCode);
    }
}

public class StatusDeserializer extends JsonDeserializer<Status> {
    @Override
    public Status deserialize(final JsonParser parser, final DeserializationContext context) throws IOException {
        return Status.fromTypeCode(parser.getValueAsInt());
    }
}

You can then tell Jackson to use your custom deserialiser for a property:

public class WarpDrive {
    private Status status; 
    @JsonDeserialize(using = StatusDeserializer.class)
    public void setStatus(final Status status) {
        this.status = status;
    }
    public Status getStatus() {
        return this.status;
    }
}

You can also configure the Jackson object mapper to use your custom deserialiser for all occurrences of the target type. See http://wiki.fasterxml.com/JacksonHowToCustomDeserializers.