Package org.starwars.server.datafetchersdelegate

Class DataFetchersDelegateHumanImpl

java.lang.Object
org.starwars.server.datafetchersdelegate.DataFetchersDelegateHumanImpl
All Implemented Interfaces:
DataFetchersDelegateHuman
@Component public class DataFetchersDelegateHumanImpl extends Object implements DataFetchersDelegateHuman
Author:
etienne-sf

  • Field Details

    • logger

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

  • Constructor Details

    • DataFetchersDelegateHumanImpl

      public DataFetchersDelegateHumanImpl()

  • Method Details

    • friends

      public List<Character> friends(graphql.schema.DataFetchingEnvironment environment, Human source)
      Description copied from interface: DataFetchersDelegateHuman
      This method loads the data for Human.friends. It may return whatever is accepted by the Spring Controller, that is:
      • A resolved value of any type (typically, a List<org.starwars.server.Character>)
      • 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.starwars.server.Character>> or a Flux<List<org.starwars.server.Character>>
      • 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.starwars.server.Character>>
      As a complement to the spring-graphql documentation, you may also return:
      • A CompletableFuture<?>, for instance CompletableFuture<List<org.starwars.server.Character>>. 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:
      friends in interface DataFetchersDelegateHuman
      Parameters:
      environment - The GraphQL DataFetchingEnvironment. It gives you access to the full GraphQL context for this DataFetcher
      source - The object from which the field is fetch. In other word: the aim of this data fetcher is to fetch the friends attribute of the origin, which is an instance of {ObjectType {name:Human, fields:{Field{name:id, type:ID!, params:[]},Field{name:name, type:String!, params:[]},Field{name:friends, type:[Character], params:[]},Field{name:appearsIn, type:[Episode]!, params:[]},Field{name:homePlanet, type:String, params:[]}}, implements Character, comments ""}. It depends on your data modle, but it typically contains the id to use in the query.

    • appearsIn

      public List<Episode> appearsIn(graphql.schema.DataFetchingEnvironment dataFetchingEnvironment, Human source)
      Description copied from interface: DataFetchersDelegateHuman
      This method loads the data for Human.appearsIn. It may return whatever is accepted by the Spring Controller, that is:
      • A resolved value of any type (typically, a List<org.starwars.server.Episode>)
      • 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.starwars.server.Episode>> or a Flux<List<org.starwars.server.Episode>>
      • 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.starwars.server.Episode>>
      As a complement to the spring-graphql documentation, you may also return:
      • A CompletableFuture<?>, for instance CompletableFuture<List<org.starwars.server.Episode>>. 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:
      appearsIn in interface DataFetchersDelegateHuman
      Parameters:
      dataFetchingEnvironment - The GraphQL DataFetchingEnvironment. It gives you access to the full GraphQL context for this DataFetcher
      source - The object from which the field is fetch. In other word: the aim of this data fetcher is to fetch the appearsIn attribute of the origin, which is an instance of {ObjectType {name:Human, fields:{Field{name:id, type:ID!, params:[]},Field{name:name, type:String!, params:[]},Field{name:friends, type:[Character], params:[]},Field{name:appearsIn, type:[Episode]!, params:[]},Field{name:homePlanet, type:String, params:[]}}, implements Character, comments ""}. It depends on your data modle, but it typically contains the id to use in the query.

    • batchLoader

      public List<Human> batchLoader(List<UUID> keys)
      Description copied from interface: DataFetchersDelegateHuman
      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 by this method must be sorted in the exact same order as the given keys list. If values are missing (no value for a given key), then the returned list must contain 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
      Specified by:
      batchLoader in interface DataFetchersDelegateHuman
      Parameters:
      keys - A list of ID's id, for which the matching objects must be returned
      Returns:
      A list of IDs