javax.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.

Author:

Gavin King, Pete Muir, David Allen

Method Summary

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

Method Detail

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

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 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 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 qualifier type, or an instance of an annotation that is not a qualifier type