Upgrade to GraphQL Java 22.2

This also documents the new subscription ordering feature as reported
and requested in #949.

Closes gh-1044

Author: bclozel

build.gradle

@@ -3,7 +3,7 @@ description = "Spring for GraphQL"
 ext {
 	moduleProjects = [project(":spring-graphql"), project(":spring-graphql-test")]
 	springFrameworkVersion = "6.1.11"
-	graphQlJavaVersion = "22.1"
+	graphQlJavaVersion = "22.2"
 	springBootVersion = "3.3.0"
 }
 

spring-graphql-docs/modules/ROOT/pages/request-execution.adoc

@@ -28,19 +28,7 @@ and `DataFetcherExceptionResolver` and `SubscriptionExceptionResolver`  beans fo
 xref:request-execution.adoc#execution.exceptions[exception resolution]. For further customizations, you can also
 declare a `GraphQlSourceBuilderCustomizer` bean, for example:
 
-[source,java,indent=0,subs="verbatim,quotes"]
-----
-@Configuration(proxyBeanMethods = false)
-class GraphQlConfig {
-
-	@Bean
-	public GraphQlSourceBuilderCustomizer sourceBuilderCustomizer() {
-		return (builder) ->
-				builder.configureGraphQl(graphQlBuilder ->
-						graphQlBuilder.executionIdProvider(new CustomExecutionIdProvider()));
-	}
-}
-----
+include-code::GraphQlConfig[]
 
 
 
@@ -409,7 +397,7 @@ request is simple enough and did not require asynchronous data fetching.
 
 
 
-[[execution.reactive-datafetcher]]
+[[execution.reactivedatafetcher]]
 == Reactive `DataFetcher`
 
 The default `GraphQlSource` builder enables support for a `DataFetcher` to return `Mono`
@@ -422,6 +410,15 @@ A reactive `DataFetcher` can rely on access to Reactor context propagated from t
 transport layer, such as from a WebFlux request handling, see
 xref:request-execution.adoc#execution.context.webflux[WebFlux Context].
 
+In the case of subscription requests, GraphQL Java will produce items as soon as they
+are available and all their requested fields were fetched. Because this involves several
+layers of asynchronous data fetching, items might be sent over the wire out of their
+original order. If you wish GraphQL Java to buffer items and retain the original order,
+you can do so by setting the `SubscriptionExecutionStrategy.KEEP_SUBSCRIPTION_EVENTS_ORDERED`
+configuration flag in the `GraphQLContext`. This can be done, for example, with a custom
+`Instrumentation`:
+
+include-code::GraphQlConfig[]
 
 
 [[execution.context]]

spring-graphql-docs/src/main/java/org/springframework/graphql/docs/execution/graphqlsource/CustomExecutionIdProvider.java

@@ -0,0 +1,27 @@
+/*
+ * Copyright 2020-2024 the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.springframework.graphql.docs.execution.graphqlsource;
+
+import graphql.execution.ExecutionId;
+import graphql.execution.ExecutionIdProvider;
+
+class CustomExecutionIdProvider implements ExecutionIdProvider {
+	@Override
+	public ExecutionId provide(String query, String operationName, Object context) {
+		return null;
+	}
+}

spring-graphql-docs/src/main/java/org/springframework/graphql/docs/execution/graphqlsource/GraphQlConfig.java

@@ -0,0 +1,33 @@
+/*
+ * Copyright 2020-2024 the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.springframework.graphql.docs.execution.graphqlsource;
+
+import org.springframework.boot.autoconfigure.graphql.GraphQlSourceBuilderCustomizer;
+import org.springframework.context.annotation.Bean;
+import org.springframework.context.annotation.Configuration;
+
+@Configuration(proxyBeanMethods = false)
+public class GraphQlConfig {
+
+	@Bean
+	public GraphQlSourceBuilderCustomizer sourceBuilderCustomizer() {
+		return (builder) ->
+				builder.configureGraphQl((graphQlBuilder) ->
+						graphQlBuilder.executionIdProvider(new CustomExecutionIdProvider()));
+	}
+
+}

spring-graphql-docs/src/main/java/org/springframework/graphql/docs/execution/reactivedatafetcher/GraphQlConfig.java

@@ -0,0 +1,50 @@
+/*
+ * Copyright 2020-2024 the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.springframework.graphql.docs.execution.reactivedatafetcher;
+
+import graphql.ExecutionResult;
+import graphql.execution.SubscriptionExecutionStrategy;
+import graphql.execution.instrumentation.InstrumentationContext;
+import graphql.execution.instrumentation.InstrumentationState;
+import graphql.execution.instrumentation.SimpleInstrumentationContext;
+import graphql.execution.instrumentation.SimplePerformantInstrumentation;
+import graphql.execution.instrumentation.parameters.InstrumentationExecutionParameters;
+
+import org.springframework.context.annotation.Bean;
+import org.springframework.context.annotation.Configuration;
+
+@Configuration(proxyBeanMethods = false)
+public class GraphQlConfig {
+
+	@Bean
+	public SubscriptionOrderInstrumentation subscriptionOrderInstrumentation() {
+		return new SubscriptionOrderInstrumentation();
+	}
+
+	static class SubscriptionOrderInstrumentation extends SimplePerformantInstrumentation {
+
+		@Override
+		public InstrumentationContext<ExecutionResult> beginExecution(InstrumentationExecutionParameters parameters,
+																InstrumentationState state) {
+			// Enable option for keeping subscription results in upstream order
+			parameters.getGraphQLContext().put(SubscriptionExecutionStrategy.KEEP_SUBSCRIPTION_EVENTS_ORDERED, true);
+			return SimpleInstrumentationContext.noOp();
+		}
+
+	}
+
+}