So, I have this page:
#Named("ManagementPage")
#ViewScoped
#Getter
#Setter
#Join(path = "/{appScope}/admin/management",
to = "/pages/scoped/managementOverview.xhtml")
#Page(
group = "kitchen",
icon = "mdi mdi-comment-text",
key = "management",
navigation = Page.Navigation.ADMIN_SCOPED,
outcome = "/pages/scoped/managementOverview.xhtml",
auth = #PageAuth(value = "MANAGER_ACCESS", scoped = true))
public class ManagementPage implements Serializable {
private static final long serialVersionUID = 1L;
#Inject
private ManagementModel model;
#PostConstruct
public void init() {
this.model.init();
}
}
It's ViewScoped. And the model for it is:
#Log4j
#Dependent
#Getter
#Setter
public class ManagementModel implements Serializable {
...
}
I want, whenever I receive an event, to refresh some UI on the frontend (I'm using JSF). For that, I've created this dispatcher:
#ApplicationScoped
public class OrderEventDispatcher {
private static final List<ManagementModel> subscriptions = new ArrayList<>();
public static void addSubscriber(ManagementModel subscriber) {
subscriptions.add(subscriber);
}
public static void removeSubscriber(ManagementModel subscriber) {
subscriptions.remove(subscriber);
}
public void observerOrderCreated(#Observes FrontendEvent frontendEvent) {
if(frontendEvent instanceof ContentItemCreatedEvent){
if(!"order".equals(((ContentItemCreatedEvent) frontendEvent).getTypeKey())){
return;
}
}
if(frontendEvent instanceof ContentItemChangedEvent){
if(!"order".equals(((ContentItemChangedEvent) frontendEvent).getTypeKey())){
return;
}
}
subscriptions.forEach(ManagementModel::orderInit);
}
}
(I have implemented a proper equals for this in my model)
For my dispatcher to work, I'm subcribing with my model to it (the methods are inside the model)
#PostConstruct
public void init() {
id = totalIds++;
OrderEventDispatcher.addSubscriber(this);
...
And then i unsubscribe before I destroy the model:
#PreDestroy
public void preDestroy() {
OrderEventDispatcher.removeSubscriber(this);
}
And finally, the methods I call from my dispatcher:
public void orderInit() {
loadMergedOrders();
initializeDonut();
PrimeFaces.current().executeScript("orderInit()");
}
I'm doing all this in order to refresh my page (even when multiple instance of the same page are open) in reaction to an event (some item is created/deleted/modified, of that the FrontendEvent takes care). Now the issue is that my PrimeFaces.current() is always returning null, I've added a breakpoint in the init() method and I tried using PrimeFaces.current() and it worked then, but then when I went through the Dispatcher and into the orderInit() with the debugger I've seen that PrimeFaces.current() now returns null. Does anyone have any idea what I'm doing wrong? If not how to fix this then maybe a different approach to solving this. Thanks for your time!
Related
I am trying to get IEventBroker injected into my code to send out notifications.
Everything else works but eventBroker never gets injected. I do not get any compile time errors.
It just comes up null when the code is executed.
I've trimmed the code because it wouldn't let me submit it.
Thanks for any help in advance!
package com.test.services.internal;
imports ...
#Component
public class EnvironmentServiceImpl implements IEnvironmentService {
#Inject
private IEventBroker eventBroker;
private EntityManagerFactory entityManagerFactory;
private EntityManager entityManager;
#Activate
#SuppressWarnings("unchecked")
protected void activateComponent() {
getAll(environments -> {
if (environments.isEmpty()) {
List<Environment> initialModel = getMockEnvironments();
initialModel.forEach(this::save);
}
});
}
#Deactivate
protected void deactivateComponent() {
}
#Override
public void getAll(Consumer<List<Environment>> taskConsumer) {
eventBroker.post(EnvironmentEventConstants.TOPIC_ENVIRONMENT_LOADED,
createEventData(EnvironmentEventConstants.TOPIC_ENVIRONMENT_LOADED, updateEnvironment.getId()));
}
private Map<String, String> createEventData(String topic, String environmentId) {
}
}
Still learning JSF and Java and having trouble understanding how to access a session bean property.
I have a LoggedUser session bean which sets the user that is logged in(using the login method).
#ManagedBean(name="loggedUser")
#Stateless
#LocalBean
#SessionScoped
public class LoggedUser {
#EJB
UserEJB userEJB;
#PersistenceContext
private EntityManager em;
private UserEntity loggedUser;
private String loginUserName;
private String loginPassword;
public LoggedUser() {}
public UserEntity getLoggedUser() {
return loggedUser;
}
public void setLoggedUser(UserEntity loggedUser) {
this.loggedUser = loggedUser;
}
public String authenticate() {
if (loggedUser == null) {
return "login.xhtml";
} else {
return "";
}
}
public String login() {
if (userEJB.validateLogin(loginUserName, loginPassword)) {
setLoggedUser(userEJB.fetchUser(loginUserName));
return "index.xhtml";
}
return "";
}
public String getLoginUserName() {
return loginUserName;
}
public void setLoginUserName(String loginUserName) {
this.loginUserName = loginUserName;
}
public String getLoginPassword() {
return loginPassword;
}
public void setLoginPassword(String loginPassword) {
this.loginPassword = loginPassword;
}
}
I want to be able to view the logged user from other areas in the application. I think I am injecting it incorrectly because loggedUser is always null when I am in a different bean for example something like..
#Stateless
#LocalBean
public class HistoryEJB {
#PersistenceContext
EntityManager em;
#ManagedProperty(value = "#{loggedUser}")
private LoggedUser loggedUser;
public LoggedUser getLoggedUser() {
return loggedUser;
}
public void setLoggedUser(LoggedUser loggedUser) {
this.loggedUser = loggedUser;
}
public void testLoggedUser() {
loggedUser.getLoggedUser();
// Just an example but would be null here - why?
}
}
How can I access this property from other areas in my application? Thanks for any help.
You can't use #ManagedProperty in an EJB and you shouldn't inject a view component into a business-tier component, period. #ManagedProperty is strictly web-tier stuff and is able to inject only and into web-tier, JSF components.
Your EJB ought to have a method that accepts a LoggedUser. This way, you can then pass your logged-in user to the EJB (which is the proper flow of data in a web application). What you have now is just turning best practice on its head.
So
Add a provideLoggedUser(LoggedUser loggedUser) method to your EJB
Call that method on your instance of UserEJB from within your managed bean
Rule of Thumb: Your EJB should not be aware of the web application
It seems you are missing the setter and getter for loggedUser. In principe it is there but it is convention to name it as follows
setProperty
and
setProperty
for a field named property. Note the capital first letter of the field name in the setter and getter!
I need to share an attribute between the beforePhase() and the afterPhase() methods of my PhaseListener, for a same JSF request.
Is the following snippet thread-safe?
public class MyPhaseListener implements PhaseListener {
private MyObject o = null;
#Override
public void beforePhase(PhaseEvent event) {
if (condition) {
o = new MyObject();
}
}
#Override
public void afterPhase(PhaseEvent event) {
if (o != null) {
o.process();
o = null;
}
}
#Override
public PhaseId getPhaseId() {
return PhaseId.RESTORE_VIEW;
}
}
If not, what are other solutions?
This is definitely not threadsafe. There's only one phase listener instance applicationwide which is shared across multiple requests. Basically, a phase listener is like an #ApplicationScoped managed bean.
Just set it as a context attribute.
public class MyPhaseListener implements PhaseListener {
#Override
public void beforePhase(PhaseEvent event) {
if (condition) {
event.getFacesContext().setAttribute("o", new MyObject());
}
}
#Override
public void afterPhase(PhaseEvent event) {
MyObject o = (MyObject) event.getFacesContext().getAttribute("o");
if (o != null) {
o.process();
}
}
#Override
public PhaseId getPhaseId() {
return PhaseId.RESTORE_VIEW;
}
}
You could use ThreadLocal for this, but it tends to have issues in environments having different classloaders, to name it: memory leak. Be sure to check for that in the given environment...
Also, you should make it sure that if the processing can be interrupted (e.g. exception...) between the beforePhase() and afterPhase() methods, the ThreadLocal should be handled appropriately...
This is what it would look like:
public class MyPhaseListener implements PhaseListener {
//if null is a valid value, no initial setting is needed
private ThreadLocal<Object> myStateObject = new ThreadLocal<Object> ();
#Override
public void beforePhase(PhaseEvent event) {
//might be needed, to guarrantee no residue from an aborted processing is in there
myState.set(null);
if (condition) {
myState.set(<Object representing the state>);
}
}
#Override
public void afterPhase(PhaseEvent event) {
try {
Object stateObject = myState.get();
if (stateObejct!=null) {
//do what you have to
}
} finally {
//to be sure
myState.remove();
}
}
}
In this article the author uses ThreadLocal too...
Also, this article is also a great eye-opener, explaining why not to share mutable instance-level information:
One thing to remember though, is that PhaseListener instances are application-wide Singletons that are referenced by the JSF Lifecycle, which itself is an application-wide Singleton.
EDIT just saw Boolean got updated to Object, adjusted example
I'm trying to intercept the method persist and update of javax.persistence.EntityManager in a Seam 3 project.
In a previous version (Seam 2) of the micro-framework I'm trying to make, I did this using an implementation of org.hibernate.Interceptor and declaring it in the persistence.xml.
But I want something more "CDI-like" now we are in a JEE6 environment.
I want that just before entering in a EntityManager.persist call, an event #BeforeTrackablePersist is thrown. The same way, I want an event #BeforeTrackableUpdate to be thrown before entering in a EntityManager.merge call. Trackable is an interface which some of my Entitys could implement in order to be intercepted before persist or merge.
I'm using Seam 3 (3.1.0.Beta3) Extended Persistence Manager :
public class EntityManagerHandler {
#SuppressWarnings("unused")
#ExtensionManaged
#Produces
#PersistenceUnit
private EntityManagerFactory entityManagerFactory;
}
So I've made a javax.enterprise.inject.spi.Extension, and tryied many ways to do that :
public class TrackableExtension implements Extension {
#Inject #BeforeTrackablePersisted
private Event<Trackable> beforeTrackablePersistedEvent;
#Inject #BeforeTrackableMerged
private Event<Trackable> beforeTrackableMergedEvent;
#SuppressWarnings("unchecked")
public void processEntityManagerTarget(#Observes final ProcessInjectionTarget<EntityManager> event) {
final InjectionTarget<EntityManager> injectionTarget = event.getInjectionTarget();
final InjectionTarget<EntityManager> injectionTargetProxy = (InjectionTarget<EntityManager>) Proxy.newProxyInstance(event.getClass().getClassLoader(), new Class[] {InjectionTarget.class}, new InvocationHandler() {
#Override
public Object invoke(final Object proxy, final Method method, final Object[] args) throws Throwable {
if ("produce".equals(method.getName())) {
final CreationalContext<EntityManager> ctx = (CreationalContext<EntityManager>) args[0];
final EntityManager entityManager = decorateEntityManager(injectionTarget, ctx);
return entityManager;
} else {
return method.invoke(injectionTarget, args);
}
}
});
event.setInjectionTarget(injectionTargetProxy);
}
public void processEntityManagerType(#Observes final ProcessAnnotatedType<EntityManager> event) {
final AnnotatedType<EntityManager> type = event.getAnnotatedType();
final AnnotatedTypeBuilder<EntityManager> builder = new AnnotatedTypeBuilder<EntityManager>().readFromType(type);
for (final AnnotatedMethod<? super EntityManager> method : type.getMethods()) {
final String name = method.getJavaMember().getName();
if (StringUtils.equals(name, "persist") || StringUtils.equals(name, "merge")) {
builder.addToMethod(method, TrackableInterceptorBindingLiteral.INSTANCE);
}
}
event.setAnnotatedType(builder.create());
}
public void processEntityManagerBean(#Observes final ProcessBean<EntityManager> event) {
final AnnotatedType<EntityManager> annotatedType = (AnnotatedType<EntityManager>)event.getAnnotated();
// not even called
}
public void processEntityManager(#Observes final ProcessProducer<?, EntityManager> processProducer) {
processProducer.setProducer(decorate(processProducer.getProducer()));
}
private Producer<EntityManager> decorate(final Producer<EntityManager> producer) {
return new Producer<EntityManager>() {
#Override
public EntityManager produce(final CreationalContext<EntityManager> ctx) {
return decorateEntityManager(producer, ctx);
}
#Override
public Set<InjectionPoint> getInjectionPoints() {
return producer.getInjectionPoints();
}
#Override
public void dispose(final EntityManager instance) {
producer.dispose(instance);
}
};
}
private EntityManager decorateEntityManager(final Producer<EntityManager> producer, final CreationalContext<EntityManager> ctx) {
final EntityManager entityManager = producer.produce(ctx);
return (EntityManager) Proxy.newProxyInstance(entityManager.getClass().getClassLoader(), new Class[] {EntityManager.class}, new InvocationHandler() {
#Override
public Object invoke(final Object proxy, final Method method, final Object[] args) throws Throwable {
final String methodName = method.getName();
if (StringUtils.equals(methodName, "persist")) {
fireEventIfTrackable(beforeTrackablePersistedEvent, args[0]);
} else if (StringUtils.equals(methodName, "merge")) {
fireEventIfTrackable(beforeTrackableMergedEvent, args[0]);
}
return method.invoke(entityManager, args);
}
private void fireEventIfTrackable(final Event<Trackable> event, final Object entity) {
if (entity instanceof Trackable) {
event.fire(Reflections.<Trackable>cast(entity));
}
}
});
}
}
In all those observer methods, only the second one (processEntityManagerType(#Observes ProcessAnnotatedType<EntityManager>)) is called ! And even with that binding addition to methods persist and merge, my Interceptor is never called (I've of course enabled it with the correct lines in beans.xml, and enabled my extension with the services/javax.enterprise.inject.spi.Extension file).
Something I've thought simple with CDI seems to be actually really hard at last... or perhaps Seam 3 does something which prevent this code from executing correctly...
Does someone know how to handle that ?
I think you're making this a little harder than what it needs to be. Firstly though, JPA and CDI integration isn't very good in Java EE 6, we're very much hoping that changes in Java EE 7 and JPA 2.1.
What you'll want to do is create your own producer for the EntityManager that will delegate to an actual instance of an EntityManager, but also fire your own events when you call the methods you're interested in. Take a look at the Seam Persistence source to see one way this can be done.
As finally my little patch for Seam Persistence was applied in SEAMPERSIST-75, it will be possible in theory to do that by extending org.jboss.seam.persistence.HibernatePersistenceProvider and override the method proxyEntityManager(EntityManager).
I have a chat application that needs to store messages to DB. But connection with DB is a little bit slow, therefore it delays response to chat client.
Is it possible to persist Message entity in separate thread? What I'm actually need in: reduce delay before send-recieve message on client.
I try to do it, but it doen't work.
Dao object:
#Stateless
public class MessagesDAO {
#PersistenceContext(type= PersistenceContextType.EXTENDED)
private EntityManager entityManager;
private PersistenceThread persistenceThread = new PersistenceThread();
//another methods
public void addMessage(Message message) {
Thread thread = new Thread(persistenceThread);
persistenceThread.setMessage(message);
thread.start();
}
private class PersistenceThread implements Runnable {
private Message message;
public void setMessage(Message message) {
this.message = message;
}
public void run() {
entityManager.persist(message);
}
}
}
Interface service that calls DAO to persist new message and then return it to clients:
#Stateless
#Path("/messages")
#Produces("application/xml")
#Consumes("application/xml")
public class MessagesServiceImpl {
#EJB
private MessagesDAO messagesDAO;
#POST
#Broadcast(resumeOnBroadcast = true)
public Message postMessage(Message message) {
messagesDAO.addMessage(message);
return message;
}
#GET
#Path("/wait")
#Suspend(outputComments = false)
public Message waitForLastMessage() {
return null;
}
//another methods
}
Thanks.
Give the #Asynchronous annotation a try:
#Stateless
public class MessagesDAO {
#PersistenceContext(type = PersistenceContextType.EXTENDED)
private EntityManager entityManager;
#Asynchronous
public void addMessage(Message message) {
entityManager.persist(message);
}
}
Just bear in mind that it requires EJB 3.1.