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Payload Column Resolver

Payload Column Resolver

Controls how the JDBC store serialises and deserialises the PAYLOAD column. Override it when the default Jackson JSON serialisation is insufficient — for example, to add type information, use a custom ObjectMapper, or store payloads in a different format.

Interface

public interface PayloadColumnResolver<T> {
    String resolve(ReferentialPayload<T> payload);
    T deserialize(String raw, Class<T> clazz);
}
  • resolve — converts the payload to the string written to PAYLOAD.
  • deserialize — converts the PAYLOAD string back to T on read.

Default Behaviour

The default resolver uses a plain ObjectMapper without type information. This works for most use cases but fails when:

  • T is an interface or abstract class — deserialisation cannot determine the concrete type.
  • The payload uses polymorphic types.
  • You need a custom ObjectMapper (e.g. with JSR-310 module, custom naming strategy).

Step 1 — Implement PayloadColumnResolver

TypedPayloadColumnResolver.java
@Component
public class TypedPayloadColumnResolver<T> implements PayloadColumnResolver<T> {

    private final ObjectMapper mapper;

    public TypedPayloadColumnResolver() {
        this.mapper = new ObjectMapper()
                .registerModule(new JavaTimeModule())
                .activateDefaultTyping(
                    BasicPolymorphicTypeValidator.builder()
                        .allowIfBaseType(Object.class)
                        .build(),
                    ObjectMapper.DefaultTyping.NON_FINAL
                );
    }

    @Override
    public String resolve(ReferentialPayload<T> payload) {
        try {
            return mapper.writeValueAsString(payload.getPayload());
        } catch (JsonProcessingException e) {
            throw new FailoverStoreException("Failed to serialise payload", e);
        }
    }

    @Override
    public T deserialize(String raw, Class<T> clazz) {
        try {
            return mapper.readValue(raw, clazz);
        } catch (JsonProcessingException e) {
            throw new FailoverStoreException("Failed to deserialise payload", e);
        }
    }
}

Next Steps