Customizing JSON-B deserializers

If your application needs finer-grained control over JSON deserialization than you can achieve via formatting annotations like @JsonbDateFormat, you may plug in your own custom instances of the Jsonb class for each input type that your GraphQL application exposes.

To do this, you'll need to create an implementation of io.smallrye.graphql.spi.EventingService and implement its overrideJsonbConfig method. An example that plugs in a custom date format for a particular class that is used as input:

public class CustomJsonbService implements EventingService {

    @Override
    public String getConfigKey() {
        return null; // activate this service always regardless of the configuration 
    }

    @Override
    public Map<String, Jsonb> overrideJsonbConfig() {
        JsonbConfig config = new JsonbConfig().withDateFormat("MM dd yyyy HH:mm Z", null);
        return Collections.singletonMap("org.example.model.MyModelClass", JsonbBuilder.create(config));
    }
}

As the discovery of eventing services uses the ServiceLoader mechanism, don't forget to add a META-INF/services/io.smallrye.graphql.spi.EventingService file that contains the fully qualified name of your implementation.