import graphql.schema.DataFetcher;

import org.springframework.aot.hint.annotation.RegisterReflectionForBinding;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.graphql.data.query.QuerydslDataFetcher;
import org.springframework.graphql.execution.RuntimeWiringConfigurer;

@Configuration
@RegisterReflectionForBinding(Book.class) (3)
public class GraphQlConfiguration {

	@Bean
	RuntimeWiringConfigurer customWiringConfigurer(BookRepository bookRepository) { (1)
		DataFetcher<Book> dataFetcher = QuerydslDataFetcher.builder(bookRepository).single();
		return (wiringBuilder) -> wiringBuilder
				.type("Query", (builder) -> builder.dataFetcher("book", dataFetcher)); (2)
	}

}

import reactor.core.publisher.Mono;

import org.springframework.aot.hint.annotation.RegisterReflectionForBinding;
import org.springframework.graphql.client.GraphQlClient;
import org.springframework.stereotype.Component;

@Component
@RegisterReflectionForBinding(Project.class) (2)
public class ProjectService {

	private final GraphQlClient graphQlClient;

	public ProjectService(GraphQlClient graphQlClient) {
		this.graphQlClient = graphQlClient;
	}

	public Mono<Project> project(String projectSlug) {
		String document = """
				query projectWithReleases($projectSlug: ID!) {
					project(slug: $projectSlug) {
						name
						releases {
							version
						}
					}
				}
				""";

		return this.graphQlClient.document(document)
				.variable("projectSlug", projectSlug)
				.retrieve("project")
				.toEntity(Project.class); (1)
	}
}