Examples with DataLoader org.dataloader.DataLoader used on opensource projects

Example 1 with DataLoader

use of org.dataloader.DataLoader in project graphql-java by graphql-java.

the class HttpMain method buildDataLoaderRegistry.

private DataLoaderRegistry buildDataLoaderRegistry() {
    BatchLoader<String, Object> friendsBatchLoader = keys -> CompletableFuture.supplyAsync(() -> loadCharactersViaHTTP(keys));
    DataLoader<String, Object> friendsDataLoader = new DataLoader<>(friendsBatchLoader);
    DataLoaderRegistry dataLoaderRegistry = new DataLoaderRegistry();
    // 
    // we make sure our dataloader is in the registry
    dataLoaderRegistry.register("friends", friendsDataLoader);
    return dataLoaderRegistry;
}

Example 2 with DataLoader

use of org.dataloader.DataLoader in project graphql-java by graphql-java.

the class HttpMain method buildStarWarsSchema.

private GraphQLSchema buildStarWarsSchema() {
    // 
    if (starWarsSchema == null) {
        // 
        // 
        // the fetcher of friends uses java-dataloader to make the circular friends fetching
        // more efficient by batching and caching the calls to load Character friends
        // 
        DataFetcher friendsFetcher = environment -> {
            DataLoaderRegistry dataloaderRegistry = asMapGet(environment.getContext(), "dataloaderRegistry");
            DataLoader friendsDataLoader = dataloaderRegistry.getDataLoader("friends");
            List<String> friendIds = asMapGet(environment.getSource(), "friends");
            return friendsDataLoader.loadMany(friendIds);
        };
        // 
        // reads a file that provides the schema types
        // 
        Reader streamReader = loadSchemaFile("starWarsSchemaAnnotated.graphqls");
        TypeDefinitionRegistry typeRegistry = new SchemaParser().parse(streamReader);
        // 
        // the runtime wiring is used to provide the code that backs the
        // logical schema
        // 
        TypeResolver characterTypeResolver = env -> {
            Map<String, Object> obj = (Map<String, Object>) env.getObject();
            String id = (String) obj.get("id");
            GraphQLSchema schema = env.getSchema();
            if (StarWarsData.isHuman(id)) {
                return (GraphQLObjectType) schema.getType("Human");
            } else {
                return (GraphQLObjectType) schema.getType("Droid");
            }
        };
        RuntimeWiring wiring = RuntimeWiring.newRuntimeWiring().type(newTypeWiring("Query").dataFetcher("hero", StarWarsData.getHeroDataFetcher()).dataFetcher("human", StarWarsData.getHumanDataFetcher()).dataFetcher("droid", StarWarsData.getDroidDataFetcher())).type(newTypeWiring("Human").dataFetcher("friends", friendsFetcher)).type(newTypeWiring("Droid").dataFetcher("friends", friendsFetcher)).type(newTypeWiring("Character").typeResolver(characterTypeResolver)).type(newTypeWiring("Episode").enumValues(StarWarsData.getEpisodeResolver())).build();
        // finally combine the logical schema with the physical runtime
        starWarsSchema = new SchemaGenerator().makeExecutableSchema(typeRegistry, wiring);
    }
    return starWarsSchema;
}

Example 3 with DataLoader

use of org.dataloader.DataLoader in project graphql-java by graphql-java.

the class BatchingExamples method starWarsExample.

void starWarsExample() {
    // a batch loader function that will be called with N or more keys for batch loading
    BatchLoader<String, Object> characterBatchLoader = new BatchLoader<String, Object>() {

        @Override
        public CompletionStage<List<Object>> load(List<String> keys) {
            // 
            return CompletableFuture.supplyAsync(() -> getCharacterDataViaBatchHTTPApi(keys));
        }
    };
    // a data loader for characters that points to the character batch loader
    DataLoader<String, Object> characterDataLoader = new DataLoader<>(characterBatchLoader);
    // 
    // use this data loader in the data fetchers associated with characters and put them into
    // the graphql schema (not shown)
    // 
    DataFetcher heroDataFetcher = new DataFetcher() {

        @Override
        public Object get(DataFetchingEnvironment environment) {
            // R2D2
            return characterDataLoader.load("2001");
        }
    };
    DataFetcher friendsDataFetcher = new DataFetcher() {

        @Override
        public Object get(DataFetchingEnvironment environment) {
            StarWarsCharacter starWarsCharacter = environment.getSource();
            List<String> friendIds = starWarsCharacter.getFriendIds();
            return characterDataLoader.loadMany(friendIds);
        }
    };
    // 
    // DataLoaderRegistry is a place to register all data loaders in that needs to be dispatched together
    // in this case there is 1 but you can have many
    // 
    DataLoaderRegistry registry = new DataLoaderRegistry();
    registry.register("character", characterDataLoader);
    // 
    // this instrumentation implementation will dispatched all the dataloaders
    // as each level fo the graphql query is executed and hence make batched objects
    // available to the query and the associated DataFetchers
    // 
    DataLoaderDispatcherInstrumentation dispatcherInstrumentation = new DataLoaderDispatcherInstrumentation(registry);
    // 
    // now build your graphql object and execute queries on it.
    // the data loader will be invoked via the data fetchers on the
    // schema fields
    // 
    GraphQL graphQL = GraphQL.newGraphQL(buildSchema()).instrumentation(dispatcherInstrumentation).build();
}