TypePerEntryMap.java

// --- The ContentMetadata enumeration

public sealed interface ContentMetadata<T> extends TypePerEntryMap.Key<T> {

    final class Score implements ContentMetadata<Double> { private Score() {} }
    final class EmbeddingId implements ContentMetadata<String> {  private EmbeddingId() {} }
    final class RerankedScore implements ContentMetadata<Double> {  private RerankedScore() {} }

    Score SCORE = new Score();
    EmbeddingId EMBEDDING_ID = new EmbeddingId();
    RerankedScore RERANKED_SCORE = new RerankedScore();
}

// --- How to use it

    private void test() {
        TypePerEntryMap<ContentMetadata> map = TypePerEntryMap.of(ContentMetadata.SCORE, 10.0, ContentMetadata.EMBEDDING_ID, "test");
        Double score = map.get(ContentMetadata.SCORE);
        String embeddingId = map.get(ContentMetadata.EMBEDDING_ID);
    }

// --- The TypePerEntryMap

public class TypePerEntryMap<K extends TypePerEntryMap.Key> {

    public interface Key<T> { }

    private final Map<Key<?>, Object> innerMap = new HashMap<>();

    public <T> void put(Key<T> key, T value) {
        innerMap.put(key, value);
    }

    public <T> T get(Key<T> key) {
        return (T) innerMap.get(key);
    }

    public static TypePerEntryMap of() {
        return new TypePerEntryMap();
    }

    public static <A> TypePerEntryMap of(Key<A> key, A value) {
        TypePerEntryMap map = new TypePerEntryMap();
        map.put(key, value);
        return map;
    }

    public static <A, B> TypePerEntryMap of(Key<A> key1, A value1, Key<B> key2, B value2) {
        TypePerEntryMap map = new TypePerEntryMap();
        map.put(key1, value1);
        map.put(key2, value2);
        return map;
    }

    public static <A, B, C> TypePerEntryMap of(Key<A> key1, A value1, Key<B> key2, B value2, Key<C> key3, C value3) {
        TypePerEntryMap map = new TypePerEntryMap();
        map.put(key1, value1);
        map.put(key2, value2);
        map.put(key3, value3);
        return map;
    }
}