org.jboss.weld.event

Class ObserverNotifier

java.lang.Object

org.jboss.weld.event.ObserverNotifier

public class ObserverNotifier
extends Object

Provides event-related operations such as observer method resolution and event delivery. An ObserverNotifier may be created with strict checks enabled. In such case event type checks are performed. Otherwise, the ObserverNotifier is called lenient. The lenient version should be used for internal dispatching of events only.

Author:

Jozef Hartinger, David Allen

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
protected static interface	ObserverNotifier.ObserverExceptionHandler There are two different strategies of exception handling for observer methods.

Field Summary

Fields

Modifier and Type	Field and Description
protected CurrentEventMetadata	currentEventMetadata

Constructor Summary

Constructors

Modifier	Constructor and Description
protected	ObserverNotifier(String contextId, TypeSafeObserverResolver resolver, ServiceRegistry services, boolean strict)

Method Summary

Modifier and Type	Method and Description
protected Resolvable	buildEventResolvable(Type eventType, Annotation... qualifiers)
protected Resolvable	buildEventResolvable(Type eventType, Set<Annotation> qualifiers)
void	clear() Clears cached observer method resolutions and event type checks.
void	fireEvent(Object event, EventMetadata metadata, Annotation... qualifiers) Delivers the given event object to observer methods resolved based on the runtime type of the event object and given event qualifiers.
void	fireEvent(Object event, Resolvable resolvable) Delivers the given event object to observer methods resolved based on the given resolvable.
void	fireEvent(Type eventType, Object event, Annotation... qualifiers) Delivers the given event object to observer methods resolved based on the given event type and qualifiers.
void	fireEvent(Type eventType, Object event, EventMetadata metadata, Annotation... qualifiers)
protected void	checkEventObjectType(Object event)
void	checkEventObjectType(Type eventType) If strict checks are enabled this method performs event type checks on the given type.
<T> void	notify(ResolvedObservers<T> observers, T event, EventMetadata metadata) Delivers the given synchronous event object to synchronous and transactional observer methods.
<T,U extends T> CompletionStage<U>	notifyAsync(ResolvedObservers<T> observers, U event, EventMetadata metadata, Executor executor) Delivers the given asynchronous event object to given observer synchronous, transactional and asynchronous observer methods.
protected <T,U extends T> CompletionStage<U>	notifyAsyncObservers(List<ObserverMethod<? super T>> observers, U event, EventMetadata metadata, Executor executor, ObserverNotifier.ObserverExceptionHandler handler)
protected <T> void	notifySyncObservers(List<ObserverMethod<? super T>> observers, T event, EventMetadata metadata, ObserverNotifier.ObserverExceptionHandler handler)
protected <T> void	notifyTransactionObservers(List<ObserverMethod<? super T>> observers, T event, EventMetadata metadata, ObserverNotifier.ObserverExceptionHandler handler)
<T> ResolvedObservers<T>	resolveObserverMethods(Resolvable resolvable) Resolves observer methods using the given resolvable.
<T> ResolvedObservers<T>	resolveObserverMethods(Type eventType, Annotation... qualifiers) Resolves observer methods based on the given event type and qualifiers.
<T> ResolvedObservers<T>	resolveObserverMethods(Type eventType, Set<Annotation> qualifiers) Resolves observer methods based on the given event type and qualifiers.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

currentEventMetadata

protected final CurrentEventMetadata currentEventMetadata

Constructor Detail

ObserverNotifier

protected ObserverNotifier(String contextId,
                           TypeSafeObserverResolver resolver,
                           ServiceRegistry services,
                           boolean strict)

Method Detail

resolveObserverMethods

public <T> ResolvedObservers<T> resolveObserverMethods(Type eventType,
                                                       Annotation... qualifiers)

Resolves observer methods based on the given event type and qualifiers. If strict checks are enabled the given type is verified.

Parameters:

event - the event object

qualifiers - given event qualifiers

Returns:

resolved observer methods

resolveObserverMethods

public <T> ResolvedObservers<T> resolveObserverMethods(Type eventType,
                                                       Set<Annotation> qualifiers)

Resolves observer methods based on the given event type and qualifiers. If strict checks are enabled the given type is verified.

Parameters:

event - the event object

qualifiers - given event qualifiers

Returns:

resolved observer methods

resolveObserverMethods

public <T> ResolvedObservers<T> resolveObserverMethods(Resolvable resolvable)

Resolves observer methods using the given resolvable.

Parameters:

resolvable - the given resolvable

Returns:

resolved observer methods

fireEvent

public void fireEvent(Object event,
                      EventMetadata metadata,
                      Annotation... qualifiers)

Delivers the given event object to observer methods resolved based on the runtime type of the event object and given event qualifiers. If strict checks are enabled the event object type is verified.

Parameters:

event - the event object

metadata - event metadata

qualifiers - event qualifiers

fireEvent

public void fireEvent(Type eventType,
                      Object event,
                      Annotation... qualifiers)

Delivers the given event object to observer methods resolved based on the given event type and qualifiers. If strict checks are enabled the given type is verified.

Parameters:

eventType - the given event type

event - the given event object

qualifiers - event qualifiers

fireEvent

public void fireEvent(Type eventType,
                      Object event,
                      EventMetadata metadata,
                      Annotation... qualifiers)

fireEvent

public void fireEvent(Object event,
                      Resolvable resolvable)

Delivers the given event object to observer methods resolved based on the given resolvable. If strict checks are enabled the event object type is verified.

Parameters:

event - the given event object

resolvable -

buildEventResolvable

protected Resolvable buildEventResolvable(Type eventType,
                                          Set<Annotation> qualifiers)

buildEventResolvable

protected Resolvable buildEventResolvable(Type eventType,
                                          Annotation... qualifiers)

clear

public void clear()

Clears cached observer method resolutions and event type checks.

checkEventObjectType

protected void checkEventObjectType(Object event)

checkEventObjectType

public void checkEventObjectType(Type eventType)

If strict checks are enabled this method performs event type checks on the given type. More specifically it verifies that no type variables nor wildcards are present within the event type. In addition, this method verifies, that the event type is not assignable to a container lifecycle event type. If strict checks are not enabled then this method does not perform any action.

Parameters:

eventType - the given event type

Throws:

IllegalArgumentException - if the strict mode is enabled and the event type contains a type variable, wildcard or is assignable to a container lifecycle event type

notify

public <T> void notify(ResolvedObservers<T> observers,
                       T event,
                       EventMetadata metadata)

Delivers the given synchronous event object to synchronous and transactional observer methods. Event metadata is made available for injection into observer methods, if needed. Asynchronous observer methods are ignored.

Parameters:

observers - the given observer methods

event - the given event object

metadata - event metadata

notifySyncObservers

protected <T> void notifySyncObservers(List<ObserverMethod<? super T>> observers,
                                       T event,
                                       EventMetadata metadata,
                                       ObserverNotifier.ObserverExceptionHandler handler)

notifyTransactionObservers

protected <T> void notifyTransactionObservers(List<ObserverMethod<? super T>> observers,
                                              T event,
                                              EventMetadata metadata,
                                              ObserverNotifier.ObserverExceptionHandler handler)

notifyAsync

public <T,U extends T> CompletionStage<U> notifyAsync(ResolvedObservers<T> observers,
                                                      U event,
                                                      EventMetadata metadata,
                                                      Executor executor)

Delivers the given asynchronous event object to given observer synchronous, transactional and asynchronous observer methods. Transactional observer methods are scheduled to be executed in the corresponding transaction phase. Then, synchronous observer methods with TransactionPhase.IN_PROGRESS are called synchronously in the current thread. Next, asynchronous observer methods are scheduled to be notified in a separate thread. Note that this method exits just after event delivery to asynchronous observer methods is scheduled. EventMetadata is made available for injection into observer methods, if needed. Note that if any of the observer methods throws an exception, it is never thrown out of this method. Instead, all the exceptions are grouped together using FireAsyncException and the returned CompletionStage fails with this compound exception. If an executor is provided then observer methods are notified using this executor. Otherwise, Weld's task executor is used.

Parameters:

observers - the given observer methods

event - the given event object

metadata - event metadata

executor - the executor to be used for asynchronous delivery - may be null

notifyAsyncObservers

protected <T,U extends T> CompletionStage<U> notifyAsyncObservers(List<ObserverMethod<? super T>> observers,
                                                                  U event,
                                                                  EventMetadata metadata,
                                                                  Executor executor,
                                                                  ObserverNotifier.ObserverExceptionHandler handler)