Add reflection for default Relay types in GraphQL Java (#307)

GraphQL Java ships interfaces for the Relay spec, as well as default
implementations for those types: Connection, Edge, PageInfo,
ConnectionCursor.

This commits adds reflection metadata for default implementations since
they are likely to be used when the GraphQL schema leverages the
interfaces provided by GraphQL Java.

Author: bclozel

metadata/com.graphql-java/graphql-java/19.2/reflect-config.json

@@ -1,4 +1,32 @@
 [
+  {
+    "name": "graphql.relay.DefaultConnection",
+    "allDeclaredMethods": true,
+    "condition": {
+      "typeReachable": "graphql.relay.Connection"
+    }
+  },
+  {
+    "name": "graphql.relay.DefaultEdge",
+    "allDeclaredMethods": true,
+    "condition": {
+      "typeReachable": "graphql.relay.Connection"
+    }
+  },
+  {
+    "name": "graphql.relay.DefaultPageInfo",
+    "allDeclaredMethods": true,
+    "condition": {
+      "typeReachable": "graphql.relay.Connection"
+    }
+  },
+  {
+    "name": "graphql.relay.DefaultConnectionCursor",
+    "allDeclaredMethods": true,
+    "condition": {
+      "typeReachable": "graphql.relay.Connection"
+    }
+  },
   {
     "name": "graphql.schema.GraphQLArgument",
     "allPublicMethods": true,

tests/src/com.graphql-java/graphql-java/19.2/src/test/java/graphql/GraphQlTests.java

@@ -8,9 +8,17 @@
 
 import java.io.IOException;
 import java.io.InputStream;
+import java.util.List;
 import java.util.function.Consumer;
 
 import graphql.introspection.IntrospectionQuery;
+import graphql.relay.Connection;
+import graphql.relay.DefaultConnection;
+import graphql.relay.DefaultConnectionCursor;
+import graphql.relay.DefaultEdge;
+import graphql.relay.DefaultPageInfo;
+import graphql.relay.Edge;
+import graphql.relay.PageInfo;
 import graphql.schema.GraphQLSchema;
 import graphql.schema.StaticDataFetcher;
 import graphql.schema.TypeResolver;
@@ -52,6 +60,22 @@ void introspectionQuery() throws Exception {
     assertThat(result.getData().toString()).contains("{__schema={queryType={name=QueryType}");
   }
 
+  @Test
+  void paginatedQuery() throws Exception {
+    PageInfo pageInfo = new DefaultPageInfo(new DefaultConnectionCursor("start"),
+            new DefaultConnectionCursor("end"), true, true);
+    Edge<Human> edge = new DefaultEdge<>(new Human(), new DefaultConnectionCursor("current"));
+    Connection<Human> connection = new DefaultConnection<>(List.of(edge), pageInfo);
+    GraphQLSchema graphQLSchema = parseSchema("starwars", runtimeWiringBuilder ->
+            runtimeWiringBuilder.type("QueryType", builder ->
+                    builder.dataFetcher("humans", new StaticDataFetcher(connection)))
+                    .type("Character", typeBuilder -> typeBuilder.typeResolver(characterTypeResolver())));
+    GraphQL graphQl = GraphQL.newGraphQL(graphQLSchema).build();
+    ExecutionResult result = graphQl.execute("{ humans { edges { node { id name } } pageInfo { startCursor } } }");
+    assertThat(result.getErrors()).isEmpty();
+    assertThat(result.getData().toString()).isEqualTo("{humans={edges=[{node={id=42, name=GraalVM}}], pageInfo={startCursor=start}}}");
+  }
+
   private GraphQLSchema parseSchema(String schemaFileName, Consumer<RuntimeWiring.Builder> consumer) throws IOException {
     try (InputStream inputStream = GraphQlTests.class.getResourceAsStream(schemaFileName + ".graphqls")) {
       TypeDefinitionRegistry registry = new SchemaParser().parse(inputStream);

tests/src/com.graphql-java/graphql-java/19.2/src/test/java/graphql/starwars/Human.java

@@ -15,12 +15,12 @@ public class Human implements Character {
 
   @Override
   public Long getId() {
-    return null;
+    return 42L;
   }
 
   @Override
   public String getName() {
-    return null;
+    return "GraalVM";
   }
 
   @Override

tests/src/com.graphql-java/graphql-java/19.2/src/test/resources/META-INF/native-image/graphql-test-metadata/reflect-config.json

@@ -1 +1,6 @@
-[]
+[
+  {
+    "name": "graphql.starwars.Human",
+    "allPublicMethods": true
+  }
+]

tests/src/com.graphql-java/graphql-java/19.2/src/test/resources/graphql/starwars.graphqls

@@ -11,6 +11,7 @@ type QueryType {
     hero(episode: Episode): Character!
     human(id : String) : Human
     droid(id: ID!): Droid
+    humans: HumanConnection
 }
 
 enum Episode {
@@ -23,7 +24,7 @@ type Human implements Character {
     id: ID!
     name: String!
     friends: [Character]
-    appearsIn: [Episode]!
+    appearsIn: [Episode]
     homePlanet: String
 }
 
@@ -43,3 +44,20 @@ interface Character {
 input NewCharacter {
     name: String
 }
+
+type HumanConnection {
+    edges: [HumanEdge]
+    pageInfo: PageInfo!
+}
+
+type HumanEdge {
+    cursor: String!
+    node: Human
+}
+
+type PageInfo {
+    hasNextPage: Boolean!
+    hasPreviousPage: Boolean!
+    startCursor: String
+    endCursor: String
+}