Polishing entity argument resolvers

Closes gh-996

Author: rstoyanchev

spring-graphql/src/main/java/org/springframework/graphql/data/federation/EntityArgumentMethodArgumentResolver.java

@@ -96,6 +96,9 @@ static DataFetchingEnvironment wrap(DataFetchingEnvironment env, List<Map<String
 	}
 
 
+	/**
+	 * Wrap the DataFetchingEnvironment to also make the representation map available.
+	 */
 	static class EntityDataFetchingEnvironment extends DelegatingDataFetchingEnvironment {
 
 		private final Map<String, Object> representation;
@@ -111,6 +114,10 @@ Map<String, Object> getRepresentation() {
 	}
 
 
+	/**
+	 * Wrap the DataFetchingEnvironment to also make representation maps available
+	 * for batched invocations.
+	 */
 	static class EntityBatchDataFetchingEnvironment extends DelegatingDataFetchingEnvironment {
 
 		private final List<Map<String, Object>> representations;

spring-graphql/src/main/java/org/springframework/graphql/data/federation/EntityArgumentsMethodArgumentResolver.java

@@ -30,8 +30,8 @@
 import org.springframework.util.Assert;
 
 /**
- * Resolver for the representation map of an entity, or for all representations
- * for the target schema type (batched handler methods).
+ * Resolver that exposes the raw representation input {@link Map},
+ * or {@link List} of maps for batched invocations.
  *
  * @author Rossen Stoyanchev
  */