#572 - Create SimpleResourceAssembler for Resource<T>.

Implement a ResourceAssembler based solely on a domain type, returning Resource<T> for the `toResource(obj)` method.

Related issues: #416

src/main/java/org/springframework/hateoas/SimpleResourceAssembler.java

@@ -0,0 +1,80 @@
+/*
+ * Copyright 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.
+ * 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;
+
+import java.util.ArrayList;
+import java.util.List;
+
+import org.springframework.util.Assert;
+
+/**
+ * A {@link ResourceAssembler} based purely on the domain type, using {@code Resource<T>} as the enclosing
+ * "resource" type.
+ *
+ * @author Greg Turnquist
+ * @since 1.0
+ */
+public interface SimpleResourceAssembler<T> extends ResourceAssembler<T, Resource<T>> {
+
+	/**
+	 * Converts the given entity into a {@link Resource}.
+	 *
+	 * @param entity
+	 * @return
+	 */
+	default Resource<T> toResource(T entity) {
+		
+		Resource<T> resource = new Resource<>(entity);
+		addLinks(resource);
+		return resource;
+	}
+
+	/**
+	 * Define links to add to every individual {@link Resource}.
+	 *
+	 * @param resource
+	 */
+	void addLinks(Resource<T> resource);
+
+	/**
+	 * Converts all given entities into resources and wraps the collection as a resource as well.
+	 *
+	 * @see #toResource(Object)
+	 * @param entities must not be {@literal null}.
+	 * @return {@link Resources} containing {@link Resource} of {@code T}.
+	 */
+	@Override
+	default Resources<Resource<T>> toResources(Iterable<? extends T> entities) {
+
+		Assert.notNull(entities, "entities must not be null!");
+		List<Resource<T>> resourceList = new ArrayList<>();
+
+		for (T entity : entities) {
+			resourceList.add(toResource(entity));
+		}
+
+		Resources<Resource<T>> resources = new Resources<>(resourceList);
+		addLinks(resources);
+		return resources;
+	}
+
+	/**
+	 * Define links to add to the {@link Resources} collection.
+	 *
+	 * @param resources
+	 */
+	void addLinks(Resources<Resource<T>> resources);
+}