I've a CDI Sterotypes which contains some of InterceptorBinding as the following: -
#Inherited
#InterceptorBinding
#Retention(RetentionPolicy.RUNTIME)
#Target({
ElementType.METHOD,
ElementType.TYPE})
#Documented
public #interface MyInterceptable {
}
#Interceptor
#MyInterceptable
public class MyInterceptor {
#AroundInvoke
public Object perform(InvocationContext context) throws Exception {
log.info("My Interceptor begin.");
Object result =context.proceed();
log.info("My Interceptor end.");
return result;
}
}
#Stereotype
#MyInterceptable
#Retention(RetentionPolicy.RUNTIME)
#Target({
ElementType.TYPE
})
#Documented
public #interface MyStereoable {
}
When I define this Sterotype at the non-EJB it is worked correctly. The message is printed before and after the doing1() execution.
#Singleton
#MyStereoable
public class MyCustomized {
public void doning1(){
//print something.
}
}
Anyhow, when I've tried to use this with the Stateless EJB, it is not worked. There is no any message printed by the Interceptor.
#Remote
public interface HelloServiceable extends Serializable {
void doning2();
}
#Stateless
#MyStereoable
public class HelloService implements HelloServiceable {
public void doing2() {
//Print something
}
}
Then I mix the case 1 and case2 as the following: -
#Stateless
#MyStereoable
public class HelloService implements HelloServiceable {
#Inject
private MyCustomized myBean;
public void doing2() {
this.myBean.doing1();
//Print something
}
}
The MyCustomized can be intercepted and the message is printed, but not for the Stateless EJB.
I'm not sure if I am misunderstand or confused about the CDI and EJB or not. Could you please help to advise further? Thank you very much for your help in advance. I'm looking forward to hearing from you soon.
Regards,
Charlee Ch.
I've changed my project from EAR/EJB project to standalone Web project. The CDI Stereotype is now worked with EJB Session Bean.
I've created a small demonstration at github. Please take note, It uses the JBoss Arquillian for testing.
I hope this information maybe useful.
Regards,
Charlee Ch.
Related
we have mixed the usage of CDI and EJB in our application. At startup, we receive the error Caused by: org.jboss.weld.context.ContextNotActiveException: WELD-001303: No active contexts for scope type javax.enterprise.context.RequestScoped.
We don't understand where exactly the problem is, so here is just the overall structure of the code:
#Stateless
public class SomeFacade {
#Inject
private SomeService someService;
}
#Stateless
public class SomeService {
#Inject
private SomeDao someDao;
}
#Stateless
public class SomeDao {
#Inject
private EntityManager entityManager;
}
#ApplicationScoped
public class EntityManagerProducer {
#Produces
#ApplicationScoped
public EntityManagerFactory createEntityManagerFactory() {
EntityManagerFactory emf = Persistence.createEntityManagerFactory("one");
return emf;
}
public void close(#Disposes EntityManagerFactory entityManagerFactory) {
entityManagerFactory.close();
}
#Produces
public EntityManager createEntityManager(EntityManagerFactory entityManagerFactory) {
return entityManagerFactory.createEntityManager();
}
}
Is there something we can change in general?
The error is raised because your code tries to access a request-scoped CDI bean in a moment when there's no request scope. Request scope is only created for incoming requests (HTTP requests via Servlet or JAX-RS, JMS MDBs, asynchronous EJB calls, etc.).
If you get this error during startup, I guess you access a request-scoped bean before CDI is fully started, e.g. from a singleton EJB. Try moving your code into a CDI that starts on start-up after CDI is initialized with:
#Dependent
public class CDIStartupBean {
public void startup(#Observes #Initialized(ApplicationScoped.class) Object event) {
// Start-up code here. The CDIStartupBean can inject request-scoped beans
}
}
Ondrej, your answer was helpful but was not quite the solution in my case.
First, I somehow resolved the start-up issues, but received the same error when handling arriving messages / REST requests. The solution was to annotate the service class with #ActivateRequestContext. This enabled CDI injections in all classes that are used by the servive.
My use case is running custom code before a controller method by annotating methods.
HandlerInterceptor seems the way to go but it seems impossible to inject dependencies into it because it needs to be registered before the context is being created.
All examples I've found so far use empty constructors (see spring boot adding http request interceptors) or autowire properties in the configuration which fails because I declare dependent beans in the same configuration (Requested bean is currently in creation: Is there an unresolvable circular reference?).
Is there a better way that does not involve AOP?
Assume that your interceptor has constructor dependencies like that:
public class CustomInterceptor extends HandlerInterceptor {
private final DependentBean bean;
public CustomInterceptor(DependentBean bean) {
this.bean = bean;
}
}
Then you can register your handler like that:
#Configuration
public WebConfig extends WebMvcConfigurerAdapater {
#Bean
public DependentBean dependentBean() {
return new DependentBean();
}
#Bean
public CustomInterceptor customInterceptor() {
return new CustomInterceptor(dependentBean());
}
#Override
public void addInterceptors(InterceptorRegistry registry) {
registry.addInterceptor(customInterceptor());
}
}
#Configuration will ensure each Bean method call return the same bean instance
Building on the answer above from Mạnh, if using component scan for dependency injection of the dependency, then that can be Autowired in the WebConfig
#Configuration
public WebConfig extends WebMvcConfigurerAdapater {
#Autowired
DependentBean dependentBean;
#Bean
public CustomInterceptor customInterceptor() {
return new CustomInterceptor(dependentBean);
}
#Override
public void addInterceptors(InterceptorRegistry registry) {
registry.addInterceptor(customInterceptor());
}
}
Also building on previous answers, and if you use Lombok, you can further simplify.
Have your interceptor implementation been a #Component
Add a private final DependentBean field to it.
Also add a #RequiredArgsConstructor annotation to it, to have Lombok generating a constructor with a single DependentBean parameter.
In your WebConfig, use the same technic to have a private final CustomInterceptor field been injected by Spring IOC.
This way the CustomInterceptor instance will be available & initialized the right way when addInterceptors will be called
Here are the corresponding code samples :
The CustomInterceptor :
#Component
#RequiredArgsConstructor
public class CustomInterceptor implements HandlerInterceptor {
private final DependentBean dependentBean;
#Override
public boolean preHandle( final HttpServletRequest request,
final HttpServletResponse response,
final Object handler ) throws Exception {
// your Interceptor Implementation goes here ...
}
}
The WebConfig :
#Configuration
#RequiredArgsConstructor
public class WebConfig implements WebMvcConfigurer {
private final CustomInterceptor customInterceptor;
#Override
public void addInterceptors( final InterceptorRegistry registry ) {
registry.addInterceptor( customInterceptor );
}
}
I need to audit invocations of ejb beans. Saying audit I mean write informations such as current logged user, method name, additional description to a database. I decided to do it by use of CDI decorator:
#Decorator
public class AccountServiceBeanDecorator implements AccountService {
#Inject
#Delegate
#Any
AccountService accountService;
#EJB
private AuditService auditService;
#Override
public Account createAccount(Account account) {
auditService.saveAudit("Method: createAccount", currentUser, "Creating account by admin");
return accountService.createAccount(account);
}
}
and the decorated class:
#Stateless
public class AccountServiceBean implements AccountService {
#Override
public Account createAccount(Account account) {
...
}
}
Now if I call AccountService from another ejb stateless bean, what will happen with transaction?:
#Stateless
public ApplicationFacadeBean implements ApplicationFacade {
#EJB
private AccountService accountService;
#Override
public Account createAccount(Account account) {
return accountService.createAccount(account);
}
}
I wanted to log transaction status in decorator (AccountServiceBeanDecorator) and decorated class (AccountServiceBean), so I injected TransactionSynchronizationRegistry as a resource in both classes:
#Decorator
public class AccountServiceBeanDecorator implements AccountService {
#Inject
#Delegate
#Any
AccountService accountService;
#EJB
private AuditService auditService;
#Resource
private TransactionSynchronizationRegistry reg;
#Override
public Account createAccount(Account account) {
log.info("%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%");
log.info("tx ({}): {}", new Object[] {reg.getTransactionStatus(), reg.getTransactionKey()});
log.info("%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%");
auditService.saveAudit("Method: createAccount", currentUser, "Creating account by admin");
return accountService.createAccount(account);
}
}
and
#Stateless
public class AccountServiceBean implements AccountService {
#Resource
private TransactionSynchronizationRegistry reg;
#Override
public Account createAccount(Account account) {
log.info("%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%");
log.info("tx ({}): {}", new Object[] {reg.getTransactionStatus(), reg.getTransactionKey()});
log.info("%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%");
...
}
}
I received strange behavior:
log from decorator
tx (0): JavaEETransactionImpl: txId=6 nonXAResource=null jtsTx=null localTxStatus=0 syncs=[com.sun.ejb.containers.ContainerSynchronization#68fb15d0]]]
NullPointerException on second log (reg is null).
Can anybody explain it to me? Wheter AccountServiceBean class is called within the same transaction as ApplicationFacade?
Thank you
first: i would not mixing ejbs with cdi interceptors. ejbs has it on interceptor implementations.
second: interceptors are executed in the same transaction as the ejb where the interceptor is around.
possible solution:
create a correct ejb interceptor
put the interceptor around the method / class
create a second ejb (MyLoggerBean) with a method like this logToDatabase(String message) and annotate this method with #TransactionAttribute(TransactionAttributeType.REQUIRES_NEW)
inside the interceptor create a class member like this: #EJB private MyLoggerBean loggerBean
inside your #AroundInvoke annotated method you could call loggerBean. logToDatabase(...)
this would create a new transaction from inside the current transaction of the ejb where the interceptor is around
--> i know my english is not very good. but i hope that you understand what i think should work. if i have the time, i make e example on github...
Hmm... what container are you using? Generally I wouldn't suspect a CDI decorator to work on an EJB... I can't think of anything in the JEE spec that I've encountered that would give evidence either way.
Faced with your problem though, I did this with an interceptor, not a decorator. These are supported by the EJB spec... Anyway, here's my code, you would need to grab the variables from the context in your case:
import java.lang.reflect.Method;
import javax.inject.Inject;
import javax.interceptor.AroundInvoke;
import javax.interceptor.Interceptor;
import javax.interceptor.InvocationContext;
public class InvocationCountInterceptor {
#Inject
private InvocationCounter counter;
#AroundInvoke
public Object intercept(InvocationContext ctx) throws Exception {
Object returnValue = ctx.proceed();
Class<? extends Object> className = ctx.getTarget().getClass();
Method methodName = ctx.getMethod();
counter.incrementCounter(className, methodName);
return returnValue;
}
}
Then whatever EJB or EJB Method you want to audit, I just added this: #Interceptors(InvocationCountInterceptor.class)
So far, I almost always worked with no-interface EJBs and have a slight understanding about the need of #Local annotation. Consider this example:
public interface MyBeanIntf { void doStuff(); }
#Stateless
public class MyBean implements MyBeanIntf { public void doStuff(){ } }
Should the MyBeanIntf be marked as #Local? I don't see any benefit from that, because even when I don't annotate it as #Local, I still can use DI to properly inject it into UI Controller:
#Named
#SessionScoped
public class TestController implements Serializable {
// injection works perfectly, even when MyBeanIntf is not marked as #Local
#Inject
private MyBeanIntf myBean;
// or even like this:
// #EJB
// private MyBeanIntf myBean;
}
Let's make it more complex:
public interface MyBeanIntf { void doStuff(); }
public class MySuperBean implements MyBeanIntf { public void doStuff() { } }
#Stateless
public class MyBean extends MySuperBean { }
Is MyBean now considered a valid Local EJB bean? I have some doubts because it implements the interface indirectly.
If your EJB implements some interface but you don't specify (neither on the EJB nor the interface itself) which interface it is (#Remote, #Local) than it's assumed that it's a #Local one.
Therefore your code:
public interface MyBeanIntf { void doStuff(); }
#Stateless
public class MyBean implements MyBeanIntf { public void doStuff(){ } }
is semantically identical to the following:
#Local
public interface MyBeanIntf { void doStuff(); }
#Stateless
public class MyBean implements MyBeanIntf { public void doStuff(){ } }
When it comes to the second part of your question, I think that section 4.9.2.1 Session Bean Superclasses from EJB 3.1 FR spec would be interesting for you. From my understanding (so it might not be correct), it seems that your bean should not be considered as exposing a valid Local interface because of the following excerpt:
#Stateless
public class A implements Foo { ... }
#Stateless
public class B extends A implements Bar { ... }
Assuming Foo and Bar are local business interfaces and there is no
associated deployment descriptor, session bean A exposes local
business interface Foo and session bean B exposes local business
interface Bar, but not Foo.
Session bean B would need to explicitly include Foo in its set of
exposed views for that interface to apply.
Update:
As an addition one more excerpt from the spec:
A session bean class is permitted to have superclasses that are
themselves session bean classes. However, there are no special rules
that apply to the processing of annotations or the deployment
descriptor for this case. For the purposes of processing a particular
session bean class, all superclass processing is identical regardless
of whether the superclasses are themselves session bean classes.
What's the best way to get EJB3, EJBLocal Object in MDB Class ?
Thanks.
The best way is injection
#MessageDriven
public class MsgBean implements MessageListener {
#EJB
private ServiceBean service;
public void onMessage(Message msg) {
service.process(msg);
}
}