Jackson2 custom deserializer factory

Question

I am porting jackson 1.6 code to jackson 2 and stumbled upon a deprecated code.

What i did in jackson 1.6 is:

CustomDeserializerFactory sf = new CustomDeserializerFactory();
mapper.setDeserializerProvider(new StdDeserializerProvider(sf));
sf.addSpecificMapping(BigDecimal.class, new BigDecimalDeserializer());
t = mapper.readValue(ts, X[].class);

Anyone knows how to do it in jackson 2?

Answer 1

To add a factory--not just a deserializer--don't use SimpleModule. Create your own Module and within it create a Deserializers object that is added to the SetUpContext. The Deserializers object will have access to similar methods that the factory did where you can get extra type information about the deserializer needed.

It will look something like this (note that it doesn't need to be an inner class):

public class MyCustomCollectionModule extends Module {

@Override
public void setupModule(final SetupContext context) {
    context.addDeserializers(new MyCustomCollectionDeserializers());
}

private static class MyCustomCollectionDeserializers implements Deserializers {

    ... 

    @Override
    public JsonDeserializer<?> findCollectionDeserializer(final CollectionType type, final DeserializationConfig config, final BeanDescription beanDesc, final TypeDeserializer elementTypeDeserializer, final JsonDeserializer<?> elementDeserializer) throws JsonMappingException {

        if (MyCustomCollection.class.equals(type.getRawClass())) {
            return new MyCustomCollectionDeserializer(type);
        }
        return null;
    }

    ...
}
}

Answer 2

In Jackson 2.0:

1. Create a Module (usually SimpleModule)
2. Register custom handlers with it.
3. Call ObjectMapper.registerModule(module);.

This is available on Jackson 1.x as well (since 1.8 or so).