我正在尝试拦截Seam 3项目中的方法persist
和update
of 。javax.persistence.EntityManager
在我尝试制作的微框架的先前版本(Seam 2)中,我org.hibernate.Interceptor
使用persistence.xml
.
但是现在我们处于 JEE6 环境中,我想要更多“类似 CDI”的东西。
我希望在进入EntityManager.persist
通话之前,@BeforeTrackablePersist
抛出一个事件。同样,我希望在进入呼叫@BeforeTrackableUpdate
之前抛出一个事件。是我的一些人可以实现的接口,以便在持久或合并之前被拦截。EntityManager.merge
Trackable
Entity
我正在使用 Seam 3 (3.1.0.Beta3) Extended Persistence Manager:
public class EntityManagerHandler {
@SuppressWarnings("unused")
@ExtensionManaged
@Produces
@PersistenceUnit
private EntityManagerFactory entityManagerFactory;
}
所以我做了一个javax.enterprise.inject.spi.Extension
,并尝试了很多方法来做到这一点:
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));
}
}
});
}
}
在所有这些观察者方法中,只有第二个 ( processEntityManagerType(@Observes ProcessAnnotatedType<EntityManager>)
) 被调用!即使对方法persist
和进行了绑定merge
,我的拦截器也永远不会被调用(我当然已经使用正确的行启用了它beans.xml
,并使用文件启用了我的扩展名services/javax.enterprise.inject.spi.Extension
)。
我认为 CDI 很简单的事情最后似乎真的很难......或者也许 Seam 3 做了一些事情,阻止了这段代码正确执行......
有人知道如何处理吗?