Package org.hibernate.event.service.spi

Interface EventListenerGroup<T>

public interface EventListenerGroup<T>
Contract for a groups of events listeners for a particular event type.

  • Method Details

    • getEventType

      EventType<T> getEventType()
      Retrieve the event type associated with this groups of listeners.
      Returns:
      The event type.

    • isEmpty

      boolean isEmpty()
      Are there no listeners registered?
      Returns:
      true if no listeners are registered; false otherwise.

    • count

      int count()

    • listeners

      @Deprecated Iterable<T> listeners()
      Deprecated.
      this is not the most efficient way for iterating the event listeners. See fireEventOnEachListener(Object, BiConsumer) and its overloaded variants for better alternatives.
      Returns:
      The Iterable.

    • addDuplicationStrategy

      void addDuplicationStrategy(DuplicationStrategy strategy)
      Mechanism to more finely control the notion of duplicates.

      For example, say you are registering listeners for an extension library. This extension library could define a "marker interface" which indicates listeners related to it and register a strategy that checks against that marker interface.

      Parameters:
      strategy - The duplication strategy

    • appendListener

      void appendListener(T listener)

    • appendListeners

      void appendListeners(T... listeners)

    • prependListener

      void prependListener(T listener)

    • prependListeners

      void prependListeners(T... listeners)

    • clear

      @Deprecated void clear()
      Deprecated.
      Use clearListeners() instead, which doesn't also reset the registered DuplicationStrategys.
      Clears both the list of event listeners and every DuplicationStrategy, including the default duplication strategy.

    • clearListeners

      void clearListeners()
      Removes all registered listeners

    • fireLazyEventOnEachListener

      @Incubating <U> void fireLazyEventOnEachListener(Supplier<U> eventSupplier, BiConsumer<T,U> actionOnEvent)
      Fires an event on each registered event listener of this group.
      Type Parameters:
      U - the kind of event
      Implementation Note:
      The first argument is a supplier so that events can avoid being created when no listener is registered; The second argument is specifically designed to avoid needing a capturing lambda.

    • fireEventOnEachListener

      @Incubating <U> void fireEventOnEachListener(U event, BiConsumer<T,U> actionOnEvent)
      Similar as fireLazyEventOnEachListener(Supplier, BiConsumer) except it doesn't use a {Supplier}. Useful when there is no need to lazily initialize the event.
      Type Parameters:
      U - the kind of event

    • fireEventOnEachListener

      @Incubating <U, X> void fireEventOnEachListener(U event, X param, EventActionWithParameter<T,U,X> actionOnEvent)
      Similar to fireEventOnEachListener(Object, BiConsumer), but allows passing a third parameter to the consumer; our code based occasionally needs a third parameter: having this additional variant allows using the optimal iteration more extensively and reduce allocations.

    • fireEventOnEachListener

      @Incubating <R, U, RL> CompletionStage<R> fireEventOnEachListener(U event, Function<RL,Function<U,CompletionStage<R>>> fun)
      Similar to fireEventOnEachListener(Object, BiConsumer), but Reactive friendly: it chains processing of the same event on each Reactive Listener, and returns a CompletionStage of type R. The various generic types allow using this for each concrete event type and flexible return types.

      Used by Hibernate Reactive

      Type Parameters:
      R - the return type of the returned CompletionStage
      U - the type of the event being fired on each listener
      RL - the type of ReactiveListener: each listener of type T will be cast to this type
      Parameters:
      event - The event being fired
      fun - The function combining each event listener with the event
      Returns:
      the composite completion stage of invoking fun(event) on each listener.

    • fireEventOnEachListener

      @Incubating <R, U, RL, X> CompletionStage<R> fireEventOnEachListener(U event, X param, Function<RL,BiFunction<U,X,CompletionStage<R>>> fun)
      Similar to fireEventOnEachListener(Object, Object, EventActionWithParameter), but Reactive friendly: it chains processing of the same event on each Reactive Listener, and returns a CompletionStage of type R. The various generic types allow using this for each concrete event type and flexible return types.

      Used by Hibernate Reactive

      Type Parameters:
      R - the return type of the returned CompletionStage
      U - the type of the event being fired on each listener
      RL - the type of ReactiveListener: each listener of type T will be cast to this type
      X - an additional parameter to be passed to the function fun
      Parameters:
      event - The event being fired
      fun - The function combining each event listener with the event
      Returns:
      the composite completion stage of invoking fun(event) on each listener.

    • fireLazyEventOnEachListener

      @Incubating <R, U, RL> CompletionStage<R> fireLazyEventOnEachListener(Supplier<U> eventSupplier, Function<RL,Function<U,CompletionStage<R>>> fun)
      Similar to fireLazyEventOnEachListener(Supplier, BiConsumer), but Reactive friendly: it chains processing of the same event on each Reactive Listener, and returns a CompletionStage of type R. The various generic types allow using this for each concrete event type and flexible return types.

      This variant expects a Supplier of the event, rather than the event directly; this is useful for the event types which are commonly configured with no listeners at all, so to allow skipping creating the event; use only for event types which are known to be expensive while the listeners are commonly empty.

      Used by Hibernate Reactive

      Type Parameters:
      R - the return type of the returned CompletionStage
      U - the type of the event being fired on each listener
      RL - the type of ReactiveListener: each listener of type T will be to this type
      Parameters:
      eventSupplier - A supplier able to produce the actual event
      fun - The function combining each event listener with the event
      Returns:
      the composite completion stage of invoking fun(event) on each listener.