Is it possible to register the jackson-datatype-jdk8
module in the Restlet org.restlet.ext.jackson
extension package? I need to take advantage of the new Optional
feature. My guess is that it should be accessible through the converter services (getConverterService()
) but I can't find anything in the documentation that suggests exactly how setting a module is possible.
I eventually pieced together from a variety of sources an answer that works with Restlet 2.3. My guess is that this will be refactored for Restlet 3 and it won't work for versions < 2.3 so be aware that this solution will most likely have a limited shelf life.
First step is to create a custom Jackson converter that implements any custom requirements you have:
public class CustomJacksonConverter extends JacksonConverter {
@Override
protected <T> JacksonRepresentation<T> create(MediaType mediaType, T source) {
ObjectMapper mapper = createMapper();
JacksonRepresentation<T> jr = new JacksonRepresentation<T>(mediaType, source);
jr.setObjectMapper(mapper);
return jr;
}
@Override
protected <T> JacksonRepresentation<T> create(Representation source, Class<T> objectClass) {
ObjectMapper mapper = createMapper();
JacksonRepresentation<T> jr = new JacksonRepresentation<T>(source, objectClass);
jr.setObjectMapper(mapper);
return jr;
}
private ObjectMapper createMapper() {
JsonFactory jsonFactory = new JsonFactory();
jsonFactory.configure(JsonGenerator.Feature.AUTO_CLOSE_TARGET, false);
ObjectMapper mapper = new ObjectMapper(jsonFactory);
mapper.registerModule(new Jdk8Module());
return mapper;
}
}
You then need to create a way of replacing the default Jackson converter with a copy of your new one:
static void replaceConverter(
Class<? extends ConverterHelper> converterClass,
ConverterHelper newConverter) {
ConverterHelper oldConverter = null;
List<ConverterHelper> converters = Engine.getInstance().getRegisteredConverters();
for (ConverterHelper converter : converters) {
if (converter.getClass().equals(converterClass)) {
converters.remove(converter);
oldConverter = converter;
break;
}
}
converters.add(newConverter);
}
You can now replace the converter in your inbound root:
replaceConverter(JacksonConverter.class, new CustomJacksonConverter());