#445 - Make ResourceAssemblerSupport extensible

Adds getters to allow implementers access to controllerClass and resourceType.

Related issues: #416

Author: gregturn

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

@@ -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> {
 
@@ -58,7 +60,7 @@ public ResourceAssemblerSupport(Class<?> controllerClass, Class<D> resourceType)
 	 * @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);
 	}
 
 	/**
@@ -87,7 +89,7 @@ protected D createResourceWithId(Object id, T entity, Object... parameters) {
 		Assert.notNull(id, "Id must not be null!");
 
 		D instance = instantiateResource(entity);
-		instance.add(linkTo(controllerClass, parameters).slash(id).withSelfRel());
+		instance.add(linkTo(this.controllerClass, parameters).slash(id).withSelfRel());
 		return instance;
 	}
 
@@ -102,4 +104,12 @@ protected D createResourceWithId(Object id, T entity, Object... parameters) {
 	protected D instantiateResource(T entity) {
 		return BeanUtils.instantiateClass(resourceType);
 	}
+
+	public Class<?> getControllerClass() {
+		return this.controllerClass;
+	}
+
+	public Class<D> getResourceType() {
+		return this.resourceType;
+	}
 }

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

@@ -20,14 +20,15 @@
 import static org.springframework.hateoas.mvc.ControllerLinkBuilder.*;
 
 import java.util.Arrays;
-import java.util.List;
 
 import org.junit.Before;
 import org.junit.Test;
+
 import org.springframework.hateoas.Identifiable;
 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;
 
@@ -85,7 +86,7 @@ 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);
 
@@ -95,7 +96,7 @@ public void convertsEntitiesToResources() {
 		PersonResource secondResource = new PersonResource();
 		secondResource.add(builder.slash(1L).withSelfRel());
 
-		assertThat(result.size(), is(2));
+		assertThat(result.getContent().size(), is(2));
 		assertThat(result, hasItems(firstResource, secondResource));
 	}
 

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

@@ -0,0 +1,104 @@
+/*
+ * Copyright 2017 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
+ *
+ *      http://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.hateoas.mvc;
+
+import static org.hamcrest.CoreMatchers.*;
+import static org.hamcrest.MatcherAssert.assertThat;
+
+import java.util.Arrays;
+
+import lombok.Data;
+import org.junit.Test;
+
+import org.springframework.hateoas.ResourceSupport;
+import org.springframework.hateoas.Resources;
+import org.springframework.stereotype.Controller;
+import org.springframework.web.bind.annotation.GetMapping;
+
+/**
+ * @author Greg Turnquist
+ */
+public class ResourceAssemblerSupportTest {
+
+	@Test
+	public void resourceAssemblerSupportShouldConvertEntitiesToResources() {
+
+		EmployeeAssembler assembler = new EmployeeAssembler();
+		Employee employee = new Employee("Frodo");
+		
+		EmployeeResource resource = assembler.toResource(employee);
+
+		assertThat(resource.getEmployee(), is(employee));
+	}
+
+	@Test
+	public void resourceAssemblerSupportShouldLetYouLookUpItsTypes() {
+
+		EmployeeAssembler assembler = new EmployeeAssembler();
+
+		assertThat(assembler.getControllerClass().getCanonicalName(), is(EmployeeController.class.getCanonicalName()));
+	}
+
+	@Test
+	public void resourceAssemblerShouldConvertCollectionOfEntitiesIntoResources() {
+
+		EmployeeAssembler assembler = new EmployeeAssembler();
+		Employee employee1 = new Employee("Frodo");
+		Employee employee2 = new Employee("Bilbo");
+
+		Resources<EmployeeResource> employees = assembler.toResources(Arrays.asList(employee1, employee2));
+
+		assertThat(employees, is(notNullValue()));
+		assertThat(employees.getContent(), hasItems(new EmployeeResource(employee1), new EmployeeResource(employee2)));
+		assertThat(employees.getLinks().size(), is(0));
+	}
+
+	//
+	// Support classes
+	//
+
+	class EmployeeAssembler extends ResourceAssemblerSupport<Employee, EmployeeResource> {
+
+		public EmployeeAssembler() {
+			super(EmployeeController.class, EmployeeResource.class);
+		}
+
+		@Override
+		public EmployeeResource toResource(Employee entity) {
+			return new EmployeeResource(entity);
+		}
+	}
+
+	@Data
+	class Employee {
+		private final String name;
+	}
+
+	@Data
+	class EmployeeResource extends ResourceSupport {
+		private final Employee employee;
+	}
+
+	@Controller
+	class EmployeeController {
+
+		@GetMapping("/employees/{id}")
+		Employee findOne(String id) {
+			return new Employee("Frodo");
+		}
+	}
+
+}