Made refactorings and added more explicit annotations to OrderController

src/main/java/com/dzone/albanoj2/example/rest/controller/OrderController.java

@@ -36,7 +36,7 @@ public ResponseEntity<Collection<OrderResource>> findAllOrders() {
 		return new ResponseEntity<>(assembler.toResourceCollection(orders), HttpStatus.OK);
 	}
 
-	@RequestMapping(method = RequestMethod.POST)
+	@RequestMapping(method = RequestMethod.POST, consumes = "application/json")
 	public ResponseEntity<OrderResource> createOrder(@RequestBody Order order) {
 		Order createdOrder = repository.create(order);
 		return new ResponseEntity<>(assembler.toResource(createdOrder), HttpStatus.CREATED);
@@ -61,7 +61,7 @@ public ResponseEntity<Void> deleteOrder(@PathVariable Long id) {
 		return new ResponseEntity<>(responseStatus);
 	}
 
-	@RequestMapping(value = "/{id}", method = RequestMethod.PUT)
+	@RequestMapping(value = "/{id}", method = RequestMethod.PUT, consumes = "application/json")
 	public ResponseEntity<OrderResource> updateOrder(@PathVariable Long id, @RequestBody Order updatedOrder) {
 		boolean wasUpdated = repository.update(id, updatedOrder);
 

src/main/java/com/dzone/albanoj2/example/rest/repository/IdGenerator.java

@@ -1,13 +1,18 @@
 package com.dzone.albanoj2.example.rest.repository;
 
+import java.util.concurrent.atomic.AtomicLong;
+
+import org.springframework.beans.factory.config.BeanDefinition;
+import org.springframework.context.annotation.Scope;
 import org.springframework.stereotype.Component;
 
 @Component
+@Scope(BeanDefinition.SCOPE_PROTOTYPE)
 public class IdGenerator {
 
-	private long nextId = 1;
+	private AtomicLong nextId = new AtomicLong(1);
 
 	public long getNextId() {
-		return nextId++;
+		return nextId.getAndIncrement();
 	}
 }

src/main/java/com/dzone/albanoj2/example/rest/repository/InMemoryRepository.java

@@ -1,6 +1,7 @@
 package com.dzone.albanoj2.example.rest.repository;
 
 import java.util.ArrayList;
+import java.util.Collections;
 import java.util.List;
 import java.util.Optional;
 
@@ -14,7 +15,7 @@ public abstract class InMemoryRepository<T extends Identifiable> {
 	@Autowired
 	private IdGenerator idGenerator;
 
-	private List<T> elements = new ArrayList<>();
+	private List<T> elements = Collections.synchronizedList(new ArrayList<>());
 
 	public T create(T element) {
 		elements.add(element);

src/main/java/com/dzone/albanoj2/example/rest/repository/OrderRepository.java

@@ -1,12 +1,10 @@
 package com.dzone.albanoj2.example.rest.repository;
 
-import org.springframework.context.annotation.Scope;
 import org.springframework.stereotype.Repository;
 
 import com.dzone.albanoj2.example.rest.domain.Order;
 
 @Repository
-@Scope("singleton")
 public class OrderRepository extends InMemoryRepository<Order> {
 
 	protected void updateIfExists(Order original, Order updated) {

src/main/java/com/dzone/albanoj2/example/rest/resource/OrderResourceAssembler.java

@@ -1,12 +1,17 @@
 package com.dzone.albanoj2.example.rest.resource;
 
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.hateoas.EntityLinks;
 import org.springframework.hateoas.Link;
 import org.springframework.stereotype.Component;
 
 import com.dzone.albanoj2.example.rest.domain.Order;
 
 @Component
 public class OrderResourceAssembler extends ResourceAssembler<Order, OrderResource> {
+
+	@Autowired
+	protected EntityLinks entityLinks;
 
 	private static final String UPDATE_REL = "update";
 	private static final String DELETE_REL = "delete";
@@ -16,7 +21,7 @@ public OrderResource toResource(Order order) {
 
 		OrderResource resource = new OrderResource(order);
 
-		final Link selfLink = entityLinks.linkToSingleResource(Order.class, order.getId());
+		final Link selfLink = entityLinks.linkToSingleResource(order);
 
 		resource.add(selfLink.withSelfRel());
 		resource.add(selfLink.withRel(UPDATE_REL));

src/main/java/com/dzone/albanoj2/example/rest/resource/ResourceAssembler.java

@@ -1,20 +1,13 @@
-package com.dzone.albanoj2.example.rest.resource;
-
-import java.util.Collection;
-import java.util.stream.Collectors;
-
-import org.springframework.beans.factory.annotation.Autowired;
-import org.springframework.hateoas.EntityLinks;
-
-public abstract class ResourceAssembler<DomainType, ResourceType> {
-
-	@Autowired
-	protected EntityLinks entityLinks;
-
-	public abstract ResourceType toResource(DomainType domainObject);
-
-	public Collection<ResourceType> toResourceCollection(Collection<DomainType> domainObjects) {
-		return domainObjects.stream().map(o -> toResource(o)).collect(Collectors.toList());
-	}
-
-}
+package com.dzone.albanoj2.example.rest.resource;
+
+import java.util.Collection;
+import java.util.stream.Collectors;
+
+public abstract class ResourceAssembler<DomainType, ResourceType> {
+
+	public abstract ResourceType toResource(DomainType domainObject);
+
+	public Collection<ResourceType> toResourceCollection(Collection<DomainType> domainObjects) {
+		return domainObjects.stream().map(o -> toResource(o)).collect(Collectors.toList());
+	}
+}

src/test/java/com/dzone/albanoj2/example/rest/test/unit/repository/IdGeneratorTest.java

@@ -0,0 +1,33 @@
+package com.dzone.albanoj2.example.rest.test.unit.repository;
+
+import org.junit.Assert;
+import org.junit.Test;
+import org.junit.runner.RunWith;
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.boot.test.context.SpringBootTest;
+import org.springframework.test.annotation.DirtiesContext;
+import org.springframework.test.annotation.DirtiesContext.ClassMode;
+import org.springframework.test.context.junit4.SpringRunner;
+
+import com.dzone.albanoj2.example.rest.repository.IdGenerator;
+
+
+@RunWith(SpringRunner.class)
+@SpringBootTest
+@DirtiesContext(classMode = ClassMode.AFTER_EACH_TEST_METHOD)
+public class IdGeneratorTest {
+
+	@Autowired
+	private IdGenerator generator1;
+
+	@Autowired
+	private IdGenerator generator2;
+
+	@Test
+	public void testMultipleGeneratorsEnsureGeneratorsDoNotInterfere() throws Exception {
+		Assert.assertEquals(1, generator1.getNextId());
+		Assert.assertEquals(2, generator1.getNextId());
+		Assert.assertEquals(1, generator2.getNextId());
+		Assert.assertEquals(2, generator2.getNextId());
+	}
+}

src/test/java/com/dzone/albanoj2/example/rest/test/unit/OrderRepositoryTest.java → src/test/java/com/dzone/albanoj2/example/rest/test/unit/repository/OrderRepositoryTest.java

@@ -1,4 +1,4 @@
-package com.dzone.albanoj2.example.rest.test.unit;
+package com.dzone.albanoj2.example.rest.test.unit.repository;
 
 import static com.dzone.albanoj2.example.rest.test.util.OrderTestUtils.*;
 
@@ -22,14 +22,14 @@
 public class OrderRepositoryTest {
 
 	private static final long NONEXISTENT_ID = 1000;
+
+	@Autowired
+	private OrderRepository repository;
 
 	@Before
 	public void setUp() {
 		repository.clear();
 	}
-
-	@Autowired
-	private OrderRepository repository;
 
 	@Test
 	public void testFindNonexistentOrderEnsureOptionalIsNotPresent() throws Exception {