CDI Events: Obtaining The InjectionPoint From EventMetaData
Starting with Java EE 7, a CDI event:
package com.airhacks.events;
import javax.enterprise.event.Event;
import javax.inject.Inject;
public class MetaDataResource {
@Inject
Event<String> event;
public void fire() {
event.fire("hey duke");
}
}
is delivered with injectable javax.enterprise.inject.spi.EventMetadata
:
import javax.enterprise.event.Observes;
import javax.enterprise.inject.spi.EventMetadata;
import javax.enterprise.inject.spi.InjectionPoint;
public class Listener {
public void onArrival(@Observes String event, EventMetadata metaData) {
InjectionPoint ip = metaData.getInjectionPoint();
Class> clazz = ip.getMember().getDeclaringClass();
String fieldName = ip.getMember().getName();
System.out.println(clazz.getName() + "-> " + fieldName);
}
}
The code creates the following output:
com.airhacks.events.MetaDataResource-> event
See you at Java EE Workshops at Munich Airport, Terminal 2 or Virtual Dedicated Workshops / consulting. Is Munich's airport too far? Learn from home: airhacks.io.
I hoped the EventMetaData would provide the calling method fire() instead of the injection point event field.
I liked that multiple @Observes all get called in one fire().
Wondering if @Observes method can be executed in a separate REQUIRES_NEW transaction. Then it can db persist new audit log entity, even when the first transaction is rollback.
Question on the side; if a @Stateless gets injected with a @Stateful, what creates and destroys the stateful? Is a new @Statefull injected at each call to the stateless? Is the stateless calling a @Remove method. How to let the @Statefull having a REQUIRES_NEW? Is this architecturally wrong?
Posted by Rene on January 02, 2016 at 07:28 PM CET #