org.axonframework.eventhandling

Interface EventHandlerInvoker

All Known Implementing Classes:

AbstractSagaManager, AnnotatedSagaManager, DeadLetteringEventHandlerInvoker, MultiEventHandlerInvoker, SimpleEventHandlerInvoker

public interface EventHandlerInvoker

Interface for an event message handler that defers handling to one or more other handlers.

Since:

3.0

Author:

Rene de Waele

Method Summary

Modifier and Type	Method and Description
boolean	canHandle(EventMessage<?> eventMessage, Segment segment) Check whether or not this invoker has handlers that can handle the given eventMessage for a given segment.
default boolean	canHandleType(Class<?> payloadType) Check whether or not this invoker has handlers that can handle the given payloadType.
void	handle(EventMessage<?> message, Segment segment) Handle the given message for the given segment.
default void	performReset() Performs any activities that are required to reset the state managed by handlers assigned to this invoker.
default <R> void	performReset(R resetContext) Performs any activities that are required to reset the state managed by handlers assigned to this invoker.
default void	segmentReleased(Segment segment) This is a way for an event processor to communicate that a segment which was being processed is released.
default boolean	supportsReset() Indicates whether the handlers managed by this invoker support a reset.

Method Detail

canHandle

boolean canHandle(@Nonnull
                  EventMessage<?> eventMessage,
                  @Nonnull
                  Segment segment)

Check whether or not this invoker has handlers that can handle the given eventMessage for a given segment.

Parameters:

eventMessage - The message to be processed

segment - The segment for which the event handler should be invoked

Returns:

true if the invoker has one or more handlers that can handle the given message, false otherwise

canHandleType

default boolean canHandleType(@Nonnull
                              Class<?> payloadType)

Check whether or not this invoker has handlers that can handle the given payloadType.

Parameters:

payloadType - The payloadType of the message to be processed

Returns:

true if the invoker has one or more handlers that can handle the given message, false otherwise

handle

void handle(@Nonnull
            EventMessage<?> message,
            @Nonnull
            Segment segment)
     throws Exception

Handle the given message for the given segment.

Callers are recommended to invoke canHandle(EventMessage, Segment) prior to invocation, but aren't required to do so. Implementations must ensure to take the given segment into account when processing messages.

Parameters:

message - The message to handle

segment - The segment for which to handle the message

Throws:

Exception - when an exception occurs while handling the message

supportsReset

default boolean supportsReset()

Indicates whether the handlers managed by this invoker support a reset.

Returns:

true if a reset is supported, otherwise false

performReset

default void performReset()

Performs any activities that are required to reset the state managed by handlers assigned to this invoker.

performReset

default <R> void performReset(@Nullable
                              R resetContext)

Performs any activities that are required to reset the state managed by handlers assigned to this invoker.

Type Parameters:

R - the type of the provided resetContext

Parameters:

resetContext - a R used to support the reset operation

segmentReleased

default void segmentReleased(Segment segment)

This is a way for an event processor to communicate that a segment which was being processed is released. This might be needed or required to free resources, are clean up state which is related to the Segment.

Parameters:

segment - the segment which was released.