Proposal: Type-safe Pub/Sub message listener API

[vinsguru]

Problem

MessageListenerAdapter relies on reflection (methodName, Object arguments) and lacks compile-time type safety. For modern Java (records, generics), this design seems to be outdated and error-prone. 😬

Proposed API

Introduce a type-safe, generic alternative for message handling:

public interface MessageHandler<T> {
    void onMessage(T message, String channel);
}

Example Usage:

public record NewsEvent(String title, String content) {
}

var listener = JsonMessageListener.of(
        NewsEvent.class,
        (event, channel) -> log.info("Received {} from {}", event, channel)
);

messageListenerContainer.addMessageListener(listener, ChannelTopic.of("news-channel"));

The existing MessageListener and MessageListenerAdapter APIs are low-level and reflection-based. They expose raw byte payloads and rely on method name resolution for dispatching, which feels outdated in modern Java applications.

Most Redis Pub/Sub use cases today exchange structured JSON data, yet developers must manually deserialize messages or use untyped adapters. A type-safe alternative such as MessageHandler<T> would provide a clearer, compile-time-safe contract for message consumption while remaining fully compatible with RedisMessageListenerContainer.