Package jakarta.enterprise.event

Interface Event<T>

Type Parameters:
T - the type of the event object
public interface Event<T>

Allows the application to fire events of a particular type.

Beans fire events via an instance of the Event interface, which may be injected: 

 @Inject
 @Any
 Event<LoggedInEvent> loggedInEvent;

The fire() method accepts an event object: 

 public void login() { 
    ...
    loggedInEvent.fire( new LoggedInEvent(user) );
 }

Any combination of qualifiers may be specified at the injection point: 

 @Inject
 @Admin
 Event<LoggedInEvent> adminLoggedInEvent;

Or, the @Any qualifier may be used, allowing the application to specify qualifiers dynamically: 

 @Inject
 @Any
 Event<LoggedInEvent> loggedInEvent;

For an injected Event:

  • the specified type is the type parameter specified at the injection point, and
  • the specified qualifiers are the qualifiers specified at the injection point.

Events may also be fired asynchronously with fireAsync(Object) and fireAsync(Object, NotificationOptions) methods

  • Method Summary

    Modifier and Type
    Method
    Description
    void
    fire(T event)
    Fires an event with the specified qualifiers and notifies observers.
    <U extends T>
    CompletionStage<U>
    fireAsync(U event)
    Fires an event asynchronously with the specified qualifiers and notifies asynchronous observers.
    <U extends T>
    CompletionStage<U>
    fireAsync(U event, NotificationOptions options)
    Fires an event asynchronously with the specified qualifiers and notifies asynchronous observers.
    <U extends T>
    Event<U>
    select(TypeLiteral<U> subtype, Annotation... qualifiers)
    Obtains a child Event for the given required type and additional required qualifiers.
    Event<T>
    select(Annotation... qualifiers)
    Obtains a child Event for the given additional required qualifiers.
    <U extends T>
    Event<U>
    select(Class<U> subtype, Annotation... qualifiers)
    Obtains a child Event for the given required type and additional required qualifiers.

  • Method Details

    • fire

      void fire(T event)

      Fires an event with the specified qualifiers and notifies observers.

      Parameters:
      event - the event object
      Throws:
      IllegalArgumentException - if the runtime type of the event object contains a type variable
      ObserverException - if a notified observer throws a checked exception, it will be wrapped and rethrown as an (unchecked) ObserverException

    • fireAsync

      <U extends T> CompletionStage<U> fireAsync(U event)

      Fires an event asynchronously with the specified qualifiers and notifies asynchronous observers.

      Type Parameters:
      U - event type
      Parameters:
      event - the event object
      Returns:
      a CompletionStage allowing further pipeline composition on the asynchronous operation. Default asynchronous execution facility is container specific. If any observer notified by this event throws an exception then the resulting CompletionStage is completed exceptionally with CompletionException that wraps all the exceptions raised by observers as suppressed exception. If no exception is thrown by observers then the resulting CompletionStage is completed normally with the event payload.
      Throws:
      IllegalArgumentException - if the runtime type of the event object contains a type variable
      Since:
      2.0

    • fireAsync

      <U extends T> CompletionStage<U> fireAsync(U event, NotificationOptions options)

      Fires an event asynchronously with the specified qualifiers and notifies asynchronous observers. A custom Executor will be used to make asynchronous calls

      Type Parameters:
      U - event type
      Parameters:
      event - the event object
      options - the notification options
      Returns:
      a CompletionStage allowing further pipeline composition on the asynchronous operation. Default asynchronous execution facility is container specific. If any observer notified by this event throws an exception then the resulting CompletionStage is completed exceptionally with CompletionException that wraps all the exceptions raised by observers as suppressed exception. If no exception is thrown by observers then the resulting CompletionStage is completed normally with the event payload.
      Throws:
      IllegalArgumentException - if the runtime type of the event object contains a type variable
      Since:
      2.0

    • select

      Event<T> select(Annotation... qualifiers)

      Obtains a child Event for the given additional required qualifiers.

      Parameters:
      qualifiers - the additional specified qualifiers
      Returns:
      the child Event
      Throws:
      IllegalArgumentException - if passed two instances of the same non repeating qualifier type, or an instance of an annotation that is not a qualifier type

    • select

      <U extends T> Event<U> select(Class<U> subtype, Annotation... qualifiers)

      Obtains a child Event for the given required type and additional required qualifiers.

      Type Parameters:
      U - the specified type
      Parameters:
      subtype - a Class representing the specified type
      qualifiers - the additional specified qualifiers
      Returns:
      the child Event
      Throws:
      IllegalArgumentException - if passed two instances of the same non repeating qualifier type, or an instance of an annotation that is not a qualifier type

    • select

      <U extends T> Event<U> select(TypeLiteral<U> subtype, Annotation... qualifiers)

      Obtains a child Event for the given required type and additional required qualifiers.

      Type Parameters:
      U - the specified type
      Parameters:
      subtype - a TypeLiteral representing the specified type
      qualifiers - the additional specified qualifiers
      Returns:
      the child Event
      Throws:
      IllegalArgumentException - if passed two instances of the same non repeating qualifier type, or an instance of an annotation that is not a qualifier type