#416 - Alter ResourceAssemblerSupport.toResources to return Resources

To avoid confusion about what to return on a Spring MVC endpoint, change toResources to not return `List<D>`, but instead `Resources<D>`. This clearly ensures when used to construct Spring MVC endpoints, will return a type Spring HATEOAS will properly marshal.

Related issues: #493
Related pull requests: #572

Author: gregturn

src/main/java/org/springframework/hateoas/mvc/ResourceAssemblerSupport.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2012-2013 the original author or authors.
+ * Copyright 2012-2018 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.
@@ -23,13 +23,15 @@
 import org.springframework.beans.BeanUtils;
 import org.springframework.hateoas.ResourceAssembler;
 import org.springframework.hateoas.ResourceSupport;
+import org.springframework.hateoas.Resources;
 import org.springframework.util.Assert;
 
 /**
  * Base class to implement {@link ResourceAssembler}s. Will automate {@link ResourceSupport} instance creation and make
  * sure a self-link is always added.
  * 
  * @author Oliver Gierke
+ * @author Greg Turnquist
  */
 public abstract class ResourceAssemblerSupport<T, D extends ResourceSupport> implements ResourceAssembler<T, D> {
 
@@ -53,12 +55,12 @@ public ResourceAssemblerSupport(Class<?> controllerClass, Class<D> resourceType)
 
 	/**
 	 * Converts all given entities into resources.
-	 * 
+	 *
 	 * @see #toResource(Object)
 	 * @param entities must not be {@literal null}.
 	 * @return
 	 */
-	public List<D> toResources(Iterable<? extends T> entities) {
+	public Resources<D> toResources(Iterable<? extends T> entities) {
 
 		Assert.notNull(entities, "Entities must not be null!");
 		List<D> result = new ArrayList<D>();
@@ -67,7 +69,7 @@ public List<D> toResources(Iterable<? extends T> entities) {
 			result.add(toResource(entity));
 		}
 
-		return result;
+		return new Resources<D>(result);
 	}
 
 	/**

src/test/java/org/springframework/hateoas/mvc/IdentifiableResourceAssemblerSupportUnitTest.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2012 the original author or authors.
+ * Copyright 2012-2018 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.
@@ -19,7 +19,6 @@
 import static org.springframework.hateoas.mvc.ControllerLinkBuilder.*;
 
 import java.util.Arrays;
-import java.util.List;
 import java.util.Optional;
 
 import org.junit.Before;
@@ -28,13 +27,15 @@
 import org.springframework.hateoas.Link;
 import org.springframework.hateoas.LinkBuilder;
 import org.springframework.hateoas.ResourceSupport;
+import org.springframework.hateoas.Resources;
 import org.springframework.hateoas.TestUtils;
 import org.springframework.web.bind.annotation.RequestMapping;
 
 /**
  * Unit tests for {@link IdentifiableResourceAssemblerSupport}.
  * 
  * @author Oliver Gierke
+ * @author Greg Turnquist
  */
 public class IdentifiableResourceAssemblerSupportUnitTest extends TestUtils {
 
@@ -81,6 +82,9 @@ public void unwrapsIdentifyablesForParameters() {
 				.hasValueSatisfying(it -> assertThat(it.endsWith("/people/id")));
 	}
 
+	/**
+	 * @see #416
+	 */
 	@Test
 	public void convertsEntitiesToResources() {
 
@@ -89,7 +93,7 @@ public void convertsEntitiesToResources() {
 		Person second = new Person();
 		second.id = 2L;
 
-		List<PersonResource> result = assembler.toResources(Arrays.asList(first, second));
+		Resources<PersonResource> result = assembler.toResources(Arrays.asList(first, second));
 
 		LinkBuilder builder = linkTo(PersonController.class);