Package org.forum.server.specific_code

Class DataFetchersDelegateTopicImpl

java.lang.Object
org.forum.server.specific_code.DataFetchersDelegateTopicImpl
All Implemented Interfaces:
DataFetchersDelegateTopic
@Component public class DataFetchersDelegateTopicImpl extends Object implements DataFetchersDelegateTopic
This class implements the access to the database : there are so many ways to do this, that the developper has still work to do. But all the GraphQL boilerplate is generated.
The GraphQLDataFetchersDelegate interface is generated from the given schema
Author:
etienne-sf

  • Field Details

    • logger

      protected org.slf4j.Logger logger
      The logger for this instance

  • Constructor Details

    • DataFetchersDelegateTopicImpl

      public DataFetchersDelegateTopicImpl()

  • Method Details

    • author

      public reactor.core.publisher.Flux<Member> author(org.dataloader.BatchLoaderEnvironment batchLoaderEnvironment, graphql.GraphQLContext graphQLContext, List<Topic> keys)
      Description copied from interface: DataFetchersDelegateTopic
      This methods loads the data for ${dataFetcher.graphQLType}.author. It is generated as the generateBatchMappingDataFetchers plugin parameter is true.
      Specified by:
      author in interface DataFetchersDelegateTopic
      Parameters:
      batchLoaderEnvironment - The environement for this batch loaded. You can extract the GraphQLContext from this parameter.
      keys - The objects for which the value for the author field must be retrieved.
      Returns:
      This method returns ${dataFetcher.batchMappingReturnType.value}, as defined by the batchMappingDataFetcherReturnType plugin parameter.
      Please look at the spring-graphql annotation for a documentation on how to return the proper values

    • posts

      public List<Post> posts(graphql.schema.DataFetchingEnvironment dataFetchingEnvironment, Topic source, Long memberId, String memberName, Date since)

    • posts

      public CompletableFuture<List<Post>> posts(graphql.schema.DataFetchingEnvironment dataFetchingEnvironment, org.dataloader.DataLoader<Long,Post> dataLoader, Topic origin, Long memberId, String memberName, Date since)
      Description copied from interface: DataFetchersDelegateTopic
      This method loads the data for Topic.posts. It may return whatever is accepted by the Spring Controller, that is:
      • A resolved value of any type (typically, a List<org.forum.server.graphql.Post>)
      • Mono and Flux for asynchronous value(s). Supported for controller methods and for any DataFetcher as described in Reactive DataFetcher. This would typically be a Mono<List<org.forum.server.graphql.Post>> or a Flux<List<org.forum.server.graphql.Post>>
      • Kotlin coroutine and Flow are adapted to Mono and Flux
      • java.util.concurrent.Callable to have the value(s) produced asynchronously. For this to work, AnnotatedControllerConfigurer must be configured with an Executor. This would typically by a Callable<List<org.forum.server.graphql.Post>>
      As a complement to the spring-graphql documentation, you may also return:
      • A CompletableFuture<?>, for instance CompletableFuture<List<org.forum.server.graphql.Post>>. This allows to use graphql-java java-dataloader to highly optimize the number of requests to the server. The principle is this one: The data loader collects all the data to load, avoid to load several times the same data, and allows parallel execution of the queries, if multiple queries are to be run.
      • A Publisher (instead of a Flux), for Subscription for instance
      Specified by:
      posts in interface DataFetchersDelegateTopic
      Parameters:
      dataFetchingEnvironment - The GraphQL DataFetchingEnvironment. It gives you access to the full GraphQL context for this DataFetcher
      dataLoader - The DataLoader allows to load several data in one query. It allows to solve the (n+1) queries issues, and greatly optimizes the response time.
      You'll find more informations here: https://github.com/graphql-java/java-dataloader
      origin - The object from which the field is fetch. In other word: the aim of this data fetcher is to fetch the posts attribute of the origin, which is an instance of {ObjectType {name:Topic, fields:{Field{name:id, type:ID!, params:[]},Field{name:date, type:Date!, params:[]},Field{name:author, type:Member!, params:[]},Field{name:publiclyAvailable, type:Boolean, params:[]},Field{name:nbPosts, type:Int, params:[]},Field{name:title, type:String!, params:[]},Field{name:content, type:String, params:[]},Field{name:posts, type:[Post]!, params:[memberId:ID,memberName:String,since:Date!]},Field{name:boardId, type:ID, params:[]},Field{name:authorId, type:ID, params:[]}}, comments ""}. It depends on your data modle, but it typically contains the id to use in the query.
      memberId - The input parameter sent in the query by the GraphQL consumer, as defined in the GraphQL schema.
      memberName - The input parameter sent in the query by the GraphQL consumer, as defined in the GraphQL schema.
      since - The input parameter sent in the query by the GraphQL consumer, as defined in the GraphQL schema.

    • unorderedReturnBatchLoader

      public List<Topic> unorderedReturnBatchLoader(List<Long> keys, org.dataloader.BatchLoaderEnvironment env)
      Description copied from interface: DataFetchersDelegateTopic
      This method loads a list of ${dataFetcher.field.name}, based on the list of id to be fetched. This method is used by graphql-java java-dataloader to highly optimize the number of requests to the server, when recursing down through the object associations.
      You can find more information on this page: graphql-java batching
      Important notes:
      • The list returned may be in any order: this method is called by the default implementation of batchLoader, which will sort the value return by this method, according to the given keys list.
      • There may be missing values (no value for a given key): the default implementation of batchLoader will replace these missing values by a null value at this key's position.
      • One of batchLoader or unorderedReturnBatchLoader must be overriden in the data fetcher implementation. If not, then a NullPointerException will be thrown at runtime, with a proper error message.
      • If your data storage implementation makes it complex to return values in the same order as the keys list, then it's easier to override unorderedReturnBatchLoader, and let the default implementation of batchLoader order the values
      • If your data storage implementation makes it easy to return values in the same order as the keys list, then the execution is a little quicker if you override batchLoader, as there would be no sort of the returned list.
      Specified by:
      unorderedReturnBatchLoader in interface DataFetchersDelegateTopic
      Parameters:
      keys - A list of ID's id, for which the matching objects must be returned
      env - The Data Loader environment
      Returns: