// Copyright 2017 Google LLC // // Licensed under the Apache License, Version 2.0 (the "License"); // you may not use this file except in compliance with the License. // You may obtain a copy of the License at // // http://www.apache.org/licenses/LICENSE-2.0 // // Unless required by applicable law or agreed to in writing, software // distributed under the License is distributed on an "AS IS" BASIS, // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. // See the License for the specific language governing permissions and // limitations under the License. package com.google.api.graphql.examples.library.graphqlserver; import com.google.common.util.concurrent.Futures; import com.google.common.util.concurrent.ListenableFuture; import com.google.common.util.concurrent.MoreExecutors; import com.google.example.library.book.v1.Book; import com.google.example.library.book.v1.BookServiceGrpc; import com.google.example.library.book.v1.ListBooksRequest; import com.google.inject.AbstractModule; import com.google.inject.Provides; import net.javacrumbs.futureconverter.java8guava.FutureConverter; import org.dataloader.BatchLoader; import org.dataloader.DataLoader; import org.dataloader.DataLoaderRegistry; import java.util.List; final class DataLoaderModule extends AbstractModule { @Provides DataLoaderRegistry dataLoaderRegistry(BookServiceGrpc.BookServiceFutureStub bookService) { // TODO: Use multibinder to modularize this, or automate this somehow BatchLoader<String, Book> bookBatchLoader = keys -> { ListenableFuture<List<Book>> listenableFuture = Futures.transform( bookService.listBooks( ListBooksRequest.newBuilder() .addAllIds(keys) .setPageSize(keys.size()) .build()), resp -> resp.getBooksList(), MoreExecutors.directExecutor()); return FutureConverter.toCompletableFuture(listenableFuture); }; DataLoaderRegistry registry = new DataLoaderRegistry(); registry.register("books", new DataLoader<>(bookBatchLoader)); return registry; } }