Package org.axonframework.messaging.eventhandling.processing.streaming.segmenting.annotation

Class SegmentParameterResolverFactory

java.lang.Object

org.axonframework.messaging.eventhandling.processing.streaming.segmenting.annotation.SegmentParameterResolverFactory

All Implemented Interfaces:

ParameterResolverFactory

public class SegmentParameterResolverFactory
extends Object
implements ParameterResolverFactory

Implementation of a ParameterResolverFactory that resolves the Segment from the ProcessingContext whenever it's available.

A streaming event processor places the Segment currently being handled in the context under Segment.RESOURCE_KEY, so a handler method may declare a Segment parameter to learn which segment it is processing -- for example to key segment-scoped state or address a segment-specific collaborator.

The resolver always matches (so a handler declaring a Segment parameter is never silently skipped) and resolves to null when no Segment is present (a processor that is not aware of segments, such as a subscribing processor). A null Segment is harmless to receive, so this resolver does not fail when one is absent.

Since:

5.3.0

Author:

Allard Buijze

Constructor Summary

Constructors

Constructor	Description
SegmentParameterResolverFactory()

Method Summary

Modifier and Type	Method	Description
@Nullable ParameterResolver<Segment>	createInstance(Executable executable, Parameter[] parameters, int parameterIndex)	If available, creates a ParameterResolver instance that can provide a parameter of type parameterType for a given message.

Methods inherited from class java.lang.Object

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

Constructor Details

SegmentParameterResolverFactory

public SegmentParameterResolverFactory()

Method Details

createInstance

public @Nullable ParameterResolver<Segment> createInstance(Executable executable,
 Parameter[] parameters,
 int parameterIndex)

Description copied from interface: ParameterResolverFactory

If available, creates a ParameterResolver instance that can provide a parameter of type parameterType for a given message.

If the ParameterResolverFactory cannot provide a suitable ParameterResolver, returns null.

Specified by:

createInstance in interface ParameterResolverFactory

Parameters:

executable - The executable (constructor or method) to inspect.

parameters - The parameters on the executable to inspect.

parameterIndex - The index of the parameter to return a ParameterResolver for.

Returns:

A suitable ParameterResolver, or null if none is found.