package io.vertx.ext.web.handler.graphql.schema.impl;
import graphql.schema.DataFetchingEnvironment;
import io.vertx.core.Context;
import io.vertx.core.Future;
import io.vertx.core.Promise;
import io.vertx.core.impl.ContextInternal;
import io.vertx.ext.web.handler.graphql.schema.VertxDataFetcher;
import java.util.Objects;
import java.util.concurrent.CompletionStage;
import java.util.function.Function;
public class FutureDataFetcherImpl<T> implements VertxDataFetcher<T> {
private final Function<DataFetchingEnvironment, Future<T>> dataFetcher;
private final Function<DataFetchingEnvironment, Context> contextProvider;
public FutureDataFetcherImpl(
Function<DataFetchingEnvironment, Future<T>> dataFetcher,
Function<DataFetchingEnvironment, Context> contextProvider
) {
this.dataFetcher = Objects.requireNonNull(dataFetcher, "dataFetcher is null");
this.contextProvider = Objects.requireNonNull(contextProvider, "contextProvider is null");
}
@Override
public CompletionStage<T> get(DataFetchingEnvironment env) {
ContextInternal context = (ContextInternal) contextProvider.apply(env);
Promise<T> promise;
if (context == null) {
promise = Promise.promise();
invokeDataFetcher(env, promise);
} else {
promise = context.promise();
context.runOnContext(v -> invokeDataFetcher(env, promise));
}
return promise.future().toCompletionStage();
}
private void invokeDataFetcher(DataFetchingEnvironment env, Promise<T> promise) {
dataFetcher.apply(env).onComplete(promise);
}
}