I have spring data rest repositories with the default post and update and delete.
I have also implemented an Event handler, now how can I add Web sockets to the event handlers?
#RepositoryEventHandler(User.class)
#Service
public class UserEventHandler {
private static final Logger LOG = LoggerFactory.getLogger(UserEventHandler.class);
#Autowired
private SmtpMailSender smtpMailSender;
#HandleAfterCreate
public void handleBeforeCreate(User u) {
}
}
// Repository class
#Transactional
#RepositoryRestResource(path = "users", collectionResourceRel = "users")
public interface UserRepository extends PagingAndSortingRepository<User, String> {
}
Related
I have the following scenario where I have one controller containing two functions (saveAudit and saveProduct). Each one persists an object,I would like to separate transactions between those functions.
throwed exception on saveProduct function should not rollback transaction on saveAudit function :
My repositories/ DAO :
public interface AuditRepository extends JpaRepository<Audit, String> {
}
public interface ProductRepository extends JpaRepository<Product, String> {
}
My controller:
#RestController
#Transactional
public class ProductController {
private final ProductreRepository productRepository;
private final Auditrepository auditRepository;
#Transactional(propagation=Propagation.REQUIRES_NEW)
void saveAudit()
{
auditRepository.saveAudit(Audit.builder().action("action1").build());
}
#PostMapping(ApiPaths.PRODUCTS)
#ResponseStatus(HttpStatus.CREATED)
public ProductDTO addNewProduct() {
ProductDTO res = productRepository.saveProduct(Product.builder().label("product1").build());
saveAudit();
int h=1/0; // => throw exception to rollback product creation
return res;
}
}
Logs:
Participating in existing transaction
its same class proxy will not work.
move below method to #Service class and inject in your controller or annotate #Transactional(propagation=Propagation.REQUIRES_NEW) in auditRepository.saveAudit
#Transactional(propagation=Propagation.REQUIRES_NEW)
public void saveAudit()
{
auditRepository.saveAudit(Audit.builder().action("action1").build());
}
For my Spring MVC application, I will have a controller which will handle all requests from paths say service/*.
urls can be like
/service/item/getitems,
/service/property/getproperties
The controller will have to load the service class at runtime based on the url specified. For example, if url is /service/item/getitems, the controller should load itemService and should be able to call itemService.getItems();
if the url is /service/property/getproperties, it should load propertyService and call propertyService.getProperties()
How can I implement the run time (dynamic) loading of services from controller?
application.yml should look like this
server:
port: 8090
servlet:
context-path: /service
ApiController.java should look like this
public abstract class ApiController<Id extends Serializable, E> {
/**
* Collection for service classes.
*
* #see AbstractService
*/
private final AbstractService<Id, E> service;
#Autowired
private ApplicationContext appContext;
public ApiController(AbstractService<Id, E> service) {
this.service = service;
}
}
AbstractService.java should look like this
public interface AbstractService<Id extends Serializable, E> {
/**
*
* #return
*/
public default Class<E> getEntityClass() {
return (Class<E>) ((ParameterizedType) this.getClass().getGenericSuperclass()).getActualTypeArguments()[1];
}
ItemController.java should look like this
#RestController
#RequestMapping(value = "/item")
public class ItemController extends ApiController<Integer, Item> {
private final ItemService itemService;
#Autowired
public ItemController(ItemService service) {
super(service);
this.service = service;
}
}
PropertyController.java should look like this
#RestController
#RequestMapping(value = "/property")
public class PropertyController extends ApiController<Integer, Property> {
private final PropertyService propertyService;
#Autowired
public PropertyController(propertyService service) {
super(service);
this.service = service;
}
}
That's what you need to do, in order to get desired results.
In normal Spring, when we want to autowire an interface, we define it's implementation in Spring context file.
What about Spring boot?
how can we achieve this?
currently we only autowire classes that are not interfaces.
Another part of this question is about using a class in a Junit class inside a Spring boot project.
If we want to use a CalendarUtil for example, if we autowire CalendarUtil, it will throw a null pointer exception. What can we do in this case? I just initialized using "new" for now...
Use #Qualifier annotation is used to differentiate beans of the same interface
Take look at Spring Boot documentation
Also, to inject all beans of the same interface, just autowire List of interface
(The same way in Spring / Spring Boot / SpringBootTest)
Example below:
#SpringBootApplication
public class DemoApplication {
public static void main(String[] args) {
SpringApplication.run(DemoApplication.class, args);
}
public interface MyService {
void doWork();
}
#Service
#Qualifier("firstService")
public static class FirstServiceImpl implements MyService {
#Override
public void doWork() {
System.out.println("firstService work");
}
}
#Service
#Qualifier("secondService")
public static class SecondServiceImpl implements MyService {
#Override
public void doWork() {
System.out.println("secondService work");
}
}
#Component
public static class FirstManager {
private final MyService myService;
#Autowired // inject FirstServiceImpl
public FirstManager(#Qualifier("firstService") MyService myService) {
this.myService = myService;
}
#PostConstruct
public void startWork() {
System.out.println("firstManager start work");
myService.doWork();
}
}
#Component
public static class SecondManager {
private final List<MyService> myServices;
#Autowired // inject MyService all implementations
public SecondManager(List<MyService> myServices) {
this.myServices = myServices;
}
#PostConstruct
public void startWork() {
System.out.println("secondManager start work");
myServices.forEach(MyService::doWork);
}
}
}
For the second part of your question, take look at this useful answers first / second
You can also make it work by giving it the name of the implementation.
Eg:
#Autowired
MyService firstService;
#Autowired
MyService secondService;
Assume that you have a GreetingService
public interface GreetingService {
void doGreetings();
}
And you have 2 implementations HelloService
#Service
#Slf4j
public class HelloService implements GreetingService{
#Override
public void doGreetings() {
log.info("Hello world!");
}
}
and HiService
#Slf4j
#Service
public class HiService implements GreetingService{
#Override
public void doGreetings() {
log.info("Hi world!");
}
}
Then you have another interface, which is BusinessService to call some business
public interface BusinessService {
void doGreetings();
}
There are some ways to do that
#1. Use #Autowired
#Component
public class BusinessServiceImpl implements BusinessService{
#Autowired
private GreetingService hiService; // Spring automatically maps the name for you, if you don't want to change it.
#Autowired
private GreetingService helloService;
#Override
public void doGreetings() {
hiService.doGreetings();
helloService.doGreetings();
}
}
In case you need to change your implementation bean name, refer to other answers, by setting the name to your bean, for example #Service("myCustomName") and applying #Qualifier("myCustomName")
#2. You can also use constructor injection
#Component
public class BusinessServiceImpl implements BusinessService {
private final GreetingService hiService;
private final GreetingService helloService;
public BusinessServiceImpl(GreetingService hiService, GreetingService helloService) {
this.hiService = hiService;
this.helloService = helloService;
}
#Override
public void doGreetings() {
hiService.doGreetings();
helloService.doGreetings();
}
}
This can be
public BusinessServiceImpl(#Qualifier("hiService") GreetingService hiService, #Qualifier("helloService") GreetingService helloService)
But I am using Spring Boot 2.6.5 and
public BusinessServiceImpl(GreetingService hiService, GreetingService helloService)
is working fine, since Spring automatically get the names for us.
#3. You can also use Map for this
#Component
#RequiredArgsConstructor
public class BusinessServiceImpl implements BusinessService {
private final Map<String, GreetingService> servicesMap; // Spring automatically get the bean name as key
#Override
public void doGreetings() {
servicesMap.get("hiService").doGreetings();
servicesMap.get("helloService").doGreetings();
}
}
List also works fine if you run all the services. But there is a case that you want to get some specific implementation, you need to define a name for it or something like that. My reference is here
For this one, I use #RequiredArgsConstructor from Lombok.
As mentioned in the comments, by using the #Qualifier annotation, you can distinguish different implementations as described in the docs.
For testing, you can use also do the same. For example:
#RunWith(SpringRunner.class)
#SpringBootTest
public class MyClassTests {
#Autowired
private MyClass testClass;
#MockBean
#Qualifier("default")
private MyImplementation defaultImpl;
#Test
public void givenMultipleImpl_whenAutowiring_thenReturnDefaultImpl() {
// your test here....
}
}
There are 2 approaches when we have autowiring of an interface with multiple implementations:
Spring #Primary annotation
In short it tells to our Spring application whenever we try to autowire our interface to use that specific implementation which is marked with the #Primary annotation. It is like a default autowiring setting. It can be used only once per cluster of implementations of an interface. → #Primary Docs
Spring #Qualifier annotation
This Spring annotation is giving us more control to select the exact implementation wherever we define a reference to our interface choosing among its options. → #Qualifier Docs
For more details follow the links to their documentation.
public interface SomeInterfaces {
void send(String message);
String getType();
}
kafka-service
#Component
public class SomeInterfacesKafkaImpl implements SomeInterfaces {
private final String type = "kafka";
#Override
public void send(String message) {
System.out.println(message + "through Kafka");
}
#Override
public String getType() {
return this.type;
}
}
redis-service
#Component
public class SomeInterfacesRedisImpl implements SomeInterfaces {
private final String type = "redis";
#Override
public void send(String message) {
System.out.println(message + "through Redis");
}
#Override
public String getType() {
return this.type;
}
}
master
#Component
public class SomeInterfacesMaster {
private final Set<SomeInterfaces> someInterfaces;
public SomeInterfacesMaster(Set<SomeInterfaces> someInterfaces) {
this.someInterfaces = someInterfaces;
}
public void sendMaster(String type){
Optional<SomeInterfaces> service =
someInterfaces
.stream()
.filter(service ->
service.getType().equals(type)
)
.findFirst();
SomeInterfaces someService =
service
.orElseThrow(() -> new RuntimeException("There is not such way for sending messages."));
someService .send(" Hello. It is a letter to ....");
}
}
test
#SpringBootTest
public class MultiImplementation {
}
#TestInstance(TestInstance.Lifecycle.PER_CLASS)
class SomeInterfacesMasterTest extends MultiImplementation {
#Autowired
private SomeInterfacesMaster someInterfacesMaster;
#Test
void sendMaster() {
someInterfacesMaster.sendMaster("kafka");
}
}
Thus, according to the Open/Closed principle, we only need to add an implementation without breaking existing code.
#Component
public class SomeInterfacesRabbitImpl implements SomeInterfaces {
private final String type = "rabbit";
#Override
public void send(String message) {
System.out.println(message + "through Rabbit");
}
#Override
public String getType() {
return this.type;
}
}
test-v2
#TestInstance(TestInstance.Lifecycle.PER_CLASS)
class SomeInterfacesMasterTestV2 extends MultiImplementation {
#Autowired
private SomeInterfacesMaster someInterfacesMaster;
#Test
void sendMasterV2() {
someInterfacesMaster.sendMaster("rabbit");
}
}
If we have multiple implementations of the same interface, Spring needs to know which one it should be autowired into a class. Here is a simple example of validator for mobile number and email address of Employee:-
Employee Class:
public class Employee {
private String mobileNumber;
private String emailAddress;
...
/** Getters & Setters omitted **/
}
Interface EmployeeValidator:
public interface EmployeeValidator {
public Employee validate(Employee employee);
}
First implementation class for Mobile Number Validator:
#Component(value="EmployeeMobileValidator")
public class EmployeeMobileValidator implements EmployeeValidator {
#Override
public Employee validate(Employee employee) {
//Mobile number Validation logic goes here.
}
}
Second implementation class for Email address Validator:
#Component(value="EmployeeEmailValidator")
public class EmployeeEmailValidator implements EmployeeValidator {
#Override
public Employee validate(Employee employee) {
//Email address validation logic goes here.
}
}
We can now autowired these above validators individually into a class.
Employee Service Interface:
public interface EmployeeService {
public void handleEmployee(Employee employee);
}
Employee Service Implementation Class
#Service
public class EmployeeServiceImpl implements EmployeeService {
/** Autowire validators individually **/
#Autowired
#Qualifier("EmployeeMobileValidator") // Autowired using qualifier for mobile validator
private EmployeeValidator mobileValidator;
#Autowired
#Qualifier("EmployeeEmailValidator") // Autowired using qualifier for email valodator
private EmployeeValidator emailValidator;
#Override
public void handleEmployee(Employee employee) {
/**You can use just one instance if you need**/
employee = mobileValidator.validate(employee);
}
}
I receive the following exception during program execution:
org.hibernate.ObjectDeletedException: deleted instance passed to merge: [ns.entity.Category#<null>]; nested exception is java.lang.IllegalArgumentException: org.hibernate.ObjectDeletedException: deleted instance passed to merge: [ns.entity.Category#<null>]
The following code throws exception:
importer.foo();
Importer service:
#Service
#Transactional
public class Importer {
#Autowired
private UserService userService;
#Autowired
private CategoryService categoryService;
#Transactional
public void foo() {
User user = userService.findByLogin("max");
categoryService.delete(user.getCategories());
}
}
UserService (uses CrudRepository):
#Service
#Repository
#Transactional
public class UserServiceImpl implements UserService {
#Autowired
private UserRepository repository;
#Override
#Transactional(readOnly = true)
public User findById(Long userId) {
return repository.findOne(userId);
}
}
CategoryService (uses CrudRepository):
#Service
#Repository
#Transactional
public class CategoryServiceImpl implements CategoryService {
#Autowired
private CategoryRepository repository;
#Override
#Transactional
public void delete(Set<Category> categories) {
repository.delete(categories);
}
}
The following code snippet in CategoryServiceImpl.delete() works without exception:
for (Category category : categories) {
Category newCat = findById(category.getCategoryId());
if (newCat != null) {
delete(newCat);
}
}
From what I understand two different transactions are used (one read only and one for deletion). Is it possible to re-use the transaction for all calls? Removing (readOnly = true) from UserServiceImpl.findById() does not help.
I thought that just one transaction should be used for all three methods (Importer.foo(), UserServiceImpl.findById(), CategoryServiceImpl.delete()) according to Spring documentation.
I have a spring (3.1) application with a service and dao layer.
I try to use requestfactory (gwt 2.4) withi this spring layer.
Here some of my class
My domain class
public class Account {
Long id;
String username;
// get, set
}
The bridge between spring and gwt
public class SpringServiceLocator implements ServiceLocator {
#Override
public Object getInstance(Class<?> clazz) {
HttpServletRequest request = RequestFactoryServlet.getThreadLocalRequest();
ServletContext servletContext = request.getSession().getServletContext();
ApplicationContext context = WebApplicationContextUtils.getWebApplicationContext(servletContext);
return context.getBean(clazz);
}
}
My account proxy
#ProxyFor(value=Account.class, locator = AccountLocator.class)
public interface AccountProxy extends EntityProxy{
public Long getId();
public String getUsername();
public void setUsername(String userName);
public void setId(Long id);
}
RequestContext class
#Service(locator = SpringServiceLocator.class, value =AccountService.class)
public interface AccountRequest extends RequestContext {
Request<List<AccountProxy>> loadAllAccounts();
}
My requestFactory class
public interface AccountRequestFactory extends RequestFactory {
AccountRequest accountRequest();
}
My spring service
public interface AccountService {
public List<Account> loadAllAccounts();
}
#Service
public class AccountServiceImpl implements AccountService{
#Autowired
private AccountDAO accountDAO;
}
Account locator to avoid to put method in the entity
public class AccountLocator extends Locator<Account, Long> {
#Autowired
private AccountDAO accountDAO;
#Override
public Account create(Class<? extends Account> clazz) {
return new Account();
}
}
applicationContext.xml
<context:annotation-config />
<context:component-scan base-package="com.calibra" />
<bean id="accountService" class="org.calibra.server.service.AccountServiceImpl"/>
<bean id="accountDAO" class="org.calibra.server.dao.AccountDAOImpl"/>
The demo work but i get this error:
com.google.web.bindery.requestfactory.server.UnexpectedException: Could not find static method with a single parameter of a key type
Also on my AccountProxy i get this complain (a warning)
The domain type org.calibra.domain.Account has no Account findAccount(java.lang.Long) method. Attempting to send a AccountProxy to the server will result in a server error.
I don't want to add a find methond in my domain class.
I tried to put this method in my spring service, but i get the same warning.
Edit with the Locator that work fine
Just strange i need to put bean in the applicationContext, context:annotation and context:component-scan seem useless
Any idea?
The domain type org.calibra.domain.Account has no Account findAccount(java.lang.Long) method.
If you don't provide a find method of some kind, RequestFactory has no way of reconstituting objects when they get to the server - it can only create brand new ones, which prevents it from merging with existing data. Take this away, and you might as well have RPC again.
If you don't want static methods, provide a Locator instance which is able to find objects. From https://developers.google.com/web-toolkit/doc/latest/DevGuideRequestFactory#locators:
What if you don't want to implement persistence code in an entity itself? To implement the required entity locator methods, create an entity locator class that extends Locator:
public class EmployeeLocator extends Locator<Employee, Long> {
#Override
public Employee create(Class<? extends Employee> clazz)
{
return new Employee();
}
...
}
Then associate it with the entity in the #ProxyFor annotation:
#ProxyFor(value = Employee.class, locator = EmployeeLocator.class)
public interface EmployeeProxy extends EntityProxy {
...
}
You'll need to implement all of the methods, not just create - and the main one you are interested in is find(Class, Long). It may be possible to use one single Locator type for all proxies - as of 2.4.0 and 2.5.0-rc1 it is safe to fail to implement getDomainType(), and all of the other methods that need to know the exact type are provided with it as an argument.
Here is an example of what this can look like with JPA and Guice, but I think the idea is clear enough that it can be implemented with Spring and whatever persistence mechanism you are using. Here, all entities are expected to implement HasVersionAndId, allowing the locator to generalize on how to invoke getVersion and getId - you might have your own base class for all persisted entities.
(from https://github.com/niloc132/tvguide-sample-parent/blob/master/tvguide-client/src/main/java/com/acme/gwt/server/InjectingLocator.java)
public class InjectingLocator<T extends HasVersionAndId> extends Locator<T, Long> {
#Inject
Provider<EntityManager> data;
#Inject
Injector injector;
#Override
public T create(Class<? extends T> clazz) {
return injector.getInstance(clazz);
}
#Override
public T find(Class<? extends T> clazz, Long id) {
return data.get().find(clazz, id);
}
#Override
public Class<T> getDomainType() {
throw new UnsupportedOperationException();//unused
}
#Override
public Long getId(T domainObject) {
return domainObject.getId();
}
#Override
public Class<Long> getIdType() {
return Long.class;
}
#Override
public Object getVersion(T domainObject) {
return domainObject.getVersion();
}
}