Polishing contribution

Closes gh-202

spring-graphql-docs/src/docs/asciidoc/index.adoc

@@ -671,6 +671,10 @@ Schema mapping handler methods can have any of the following method arguments:
 | For access to field arguments with conversion.
 See <<controllers-schema-mapping-argument>>.
 
+| `@ProjectedPayload` Interface
+| For access to field arguments through a project interface.
+See <<controllers-schema-mapping-projectedpayload-argument>>.
+
 | Source
 | For access to the source (i.e. parent/container) instance of the field.
 See <<controllers-schema-mapping-source>>.
@@ -740,50 +744,23 @@ You can use `@Argument` on a `Map<String, Object>` argument, to obtain all argum
 values. The name attribute on `@Argument` must not be set.
 
 
-[[controllers-schema-mapping-source]]
-==== Source
+[[controllers-schema-mapping-projectedpayload-argument]]
+==== `@ProjectPayload` Interface
 
-In GraphQL Java, the `DataFetchingEnvironment` provides access to the source (i.e.
-parent/container) instance of the field. To access this, simply declare a method parameter
-of the expected target type.
-
-[source,java,indent=0,subs="verbatim,quotes"]
-----
-	@Controller
-	public class BookController {
-
-		@SchemaMapping
-		public Author author(Book book) {
-			// ...
-		}
-	}
-----
-
-The source method argument also helps to determine the type name for the mapping.
-If the simple name of the Java class matches the GraphQL type, then there is no need to
-explicitly specify the type name in the `@SchemaMapping` annotation.
-
-[TIP]
-====
-A <<controllers-batch-mapping>> handler method can batch load all authors for a query,
-given a list of source/parent books objects.
-====
-
-
-[[controllers-schema-mapping-argument-projections]]
-==== Argument Projections
-
-When accessing individual arguments from a GraphQL request, interface projections can
-be useful to access arguments through a well-defined interface.
-
-Spring Data's `@ProjectedPayload` can be used to annotate projection interfaces that
-can be declared as handler method arguments. Payload projection can work on top-level
-arguments (`DataFetchingEnvironment.getArguments()`). Alternatively, projections can
-be applied on individual arguments by using `@Argument` with a projected payload interface.
-
-Argument projections are provided by https://docs.spring.io/spring-data/commons/docs/current/reference/html/#projections.interfaces[Spring Data's Interface projections]
+As an alternative to using complete Objects with <<controllers-schema-mapping-argument>>,
+you can also use a projection interface to access GraphQL request arguments through a
+well-defined, minimal interface. Argument projections are provided by
+https://docs.spring.io/spring-data/commons/docs/current/reference/html/#projections.interfaces[Spring Data's Interface projections]
 when Spring Data is on the class path.
 
+To make use of this, create an interface annotated with `@ProjectedPayload` and declare
+it as a controller method parameter. If the parameter is annotated with `@Argument`,
+it applies to an individual argument within the `DataFetchingEnvironment.getArguments()`
+map. When declared without `@Argument`, the projection works on top-level arguments in
+the complete arguments map.
+
+For example:
+
 [source,java,indent=0,subs="verbatim,quotes"]
 ----
 	@Controller
@@ -817,6 +794,35 @@ when Spring Data is on the class path.
 ----
 
 
+[[controllers-schema-mapping-source]]
+==== Source
+
+In GraphQL Java, the `DataFetchingEnvironment` provides access to the source (i.e.
+parent/container) instance of the field. To access this, simply declare a method parameter
+of the expected target type.
+
+[source,java,indent=0,subs="verbatim,quotes"]
+----
+	@Controller
+	public class BookController {
+
+		@SchemaMapping
+		public Author author(Book book) {
+			// ...
+		}
+	}
+----
+
+The source method argument also helps to determine the type name for the mapping.
+If the simple name of the Java class matches the GraphQL type, then there is no need to
+explicitly specify the type name in the `@SchemaMapping` annotation.
+
+[TIP]
+====
+A <<controllers-batch-mapping>> handler method can batch load all authors for a query,
+given a list of source/parent books objects.
+====
+
 
 [[controllers-schema-mapping-data-loader]]
 ==== `DataLoader`

spring-graphql/src/main/java/org/springframework/graphql/data/method/annotation/support/AnnotatedControllerConfigurer.java

@@ -87,6 +87,7 @@ public class AnnotatedControllerConfigurer
 	private final static boolean springDataPresent = ClassUtils.isPresent(
 			"org.springframework.data.projection.SpelAwareProxyProjectionFactory",
 			AnnotatedControllerConfigurer.class.getClassLoader());
+
 	private final static boolean springSecurityPresent = ClassUtils.isPresent(
 			"org.springframework.security.core.context.SecurityContext",
 			AnnotatedControllerConfigurer.class.getClassLoader());
@@ -121,6 +122,7 @@ public class AnnotatedControllerConfigurer
 	public void afterPropertiesSet() {
 		this.argumentResolvers = new HandlerMethodArgumentResolverComposite();
 		if (springDataPresent) {
+			// This must be ahead of ArgumentMethodArgumentResolver
 			this.argumentResolvers.addResolver(new ProjectedPayloadMethodArgumentResolver());
 		}
 		this.argumentResolvers.addResolver(new ArgumentMapMethodArgumentResolver());

spring-graphql/src/main/java/org/springframework/graphql/data/method/annotation/support/ProjectedPayloadMethodArgumentResolver.java

@@ -30,14 +30,16 @@ import org.springframework.graphql.data.method.HandlerMethodArgumentResolver;
 import org.springframework.graphql.data.method.annotation.Argument;
 
 /**
- * Resolver to obtain a {@link ProjectedPayload @ProjectedPayload}
- * for {@link  DataFetchingEnvironment#getArguments()}.
+ * Resolver to obtain an {@link ProjectedPayload @ProjectedPayload},
+ * either based on the complete {@link  DataFetchingEnvironment#getArguments()}
+ * map, or based on a specific argument within the map when the method
+ * parameter is annotated with {@code @Argument}.
  *
- * <p>Projected payloads consist of the projection interface and accessor methods.
- * Projections can be closed or open projections. Closed projections use interface
- * getter methods to access underlying properties directly. Open projection methods
- * make use of the {@code @Value} annotation to evaluate SpEL expressions against the
- * underlying {@code target} object.
+ * <p>Projected payloads consist of the projection interface and accessor
+ * methods. Projections can be closed or open projections. Closed projections
+ * use interface getter methods to access underlying properties directly.
+ * Open projection methods make use of the {@code @Value} annotation to
+ * evaluate SpEL expressions against the underlying {@code target} object.
  *
  * <p>For example:
  * <pre class="code">
@@ -62,6 +64,17 @@ public class ProjectedPayloadMethodArgumentResolver implements HandlerMethodArgu
 	private final SpelAwareProxyProjectionFactory projectionFactory = new SpelAwareProxyProjectionFactory();
 
 
+	@Override
+	public void setBeanFactory(BeanFactory beanFactory) throws BeansException {
+		this.projectionFactory.setBeanFactory(beanFactory);
+	}
+
+	@Override
+	public void setBeanClassLoader(ClassLoader classLoader) {
+		this.projectionFactory.setBeanClassLoader(classLoader);
+	}
+
+
 	@Override
 	public boolean supportsParameter(MethodParameter parameter) {
 		Class<?> type = parameter.getParameterType();
@@ -88,13 +101,4 @@ public class ProjectedPayloadMethodArgumentResolver implements HandlerMethodArgu
 		return this.projectionFactory.createProjection(projectionType, projectionSource);
 	}
 
-	@Override
-	public void setBeanFactory(BeanFactory beanFactory) throws BeansException {
-		this.projectionFactory.setBeanFactory(beanFactory);
-	}
-
-	@Override
-	public void setBeanClassLoader(ClassLoader classLoader) {
-		this.projectionFactory.setBeanClassLoader(classLoader);
-	}
 }

spring-graphql/src/test/java/org/springframework/graphql/data/method/annotation/support/SchemaMappingInvocationTests.java

@@ -99,7 +99,7 @@ public class SchemaMappingInvocationTests {
 	}
 
 	@Test
-	void queryWithProjectedArgument() {
+	void queryWithProjectionOnArgumentsMap() {
 		String query = "{ " +
 				"  booksByProjectedArguments(author:\"Orwell\") { " +
 				"    id" +
@@ -116,7 +116,7 @@ public class SchemaMappingInvocationTests {
 	}
 
 	@Test
-	void booksByProjectedCriteria() {
+	void queryWithProjectionOnNamedArgument() {
 		String query = "{ " +
 				"  booksByProjectedCriteria(criteria: {author:\"Orwell\"}) { " +
 				"    id" +