The object type returned by DataLoaderFactory.newDataLoaderWithTry().dispatcher is inconsistent with the specified generic type.

[nenryo]

Describe the bug
I am new to this library. When learning this library, I found that the object type returned by DataLoaderFactory.newDataLoaderWithTry().dispatcher() is inconsistent with the specified generic type.

To Reproduce

[bbakerman]

You are right - is is inconsistent when the Try mechanism is used

Data loader is declared as DataLoader<K, V> and hence we get public CompletableFuture<List<V>> dispatch()

The Try wrappers are unwrapped by the engine code and hence the CompletableFuture<V> load(K key) values do come back as the expected V type but the dispatch gives back the raw values and does not unwrap them.

                        } else if (value instanceof Try) {
                            // we allow the batch loader to return a Try so we can better represent a computation
                            // that might have worked or not.
                            Try<V> tryValue = (Try<V>) value;
                            if (tryValue.isSuccess()) {
                                future.complete(tryValue.get());
                            } else {
                                stats.incrementLoadErrorCount(new IncrementLoadErrorCountStatisticsContext<>(key, callContext));
                                future.completeExceptionally(tryValue.getThrowable());
                                clearCacheKeys.add(keys.get(idx));
                            }

Perhaps it should unwrap them when giving his back - I would have to think on that more.

The other option would be to have something like DataLoader<K,V,BatchV> where BatchV is the generic type of value coming back from the BatchLoader but thats too viral a change really.

ps. We mostly expect people to use the values via load(k) calls rather than the values coming back via dispatch but you are right its inconsistent.