Package org.axonframework.common.nullability

Class AnnotationBasedNullabilityResolver

java.lang.Object

org.axonframework.common.nullability.AnnotationBasedNullabilityResolver

All Implemented Interfaces:

NullabilityResolver

@Internal
public class AnnotationBasedNullabilityResolver
extends Object
implements NullabilityResolver

NullabilityResolver reporting a parameter as Nullability.NULLABLE when it carries an annotation whose simple name is Nullable, regardless of which library declares it.

This covers the runtime-visible variants, whichever position they occupy: jspecify's org.jspecify.annotations.Nullable in the type-use position, and jakarta.annotation.Nullable or JSR-305's javax.annotation.Nullable in the declaration position. It cannot cover org.jetbrains.annotations.Nullable, which uses RetentionPolicy.CLASS retention and is therefore absent from the class file at runtime.

Registered through this module's META-INF/services file and left unannotated, so it sits at Priority.NEUTRAL and any resolver that can speak authoritatively for a subset of parameters, such as one backed by a language's own type information, outranks it.

Never reports Nullability.NON_NULL: an unannotated Java parameter says nothing about whether it accepts null, so anything other than an explicit Nullable annotation yields Nullability.UNKNOWN.

Marked Internal as it is registered automatically and not meant to be referenced directly.

Since:

5.3.0

Author:

Mateusz Nowak

See Also:

• NullabilityResolver

Constructor Summary

Constructors

Constructor	Description
AnnotationBasedNullabilityResolver()	Constructs the resolver.

Method Summary

Modifier and Type	Method	Description
Nullability	resolve(Parameter parameter)	Determines the declared Nullability of the given parameter.

Methods inherited from class java.lang.Object

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

Constructor Details

AnnotationBasedNullabilityResolver

public AnnotationBasedNullabilityResolver()

Constructs the resolver. Invoked by the ServiceLoader.

Method Details

resolve

public Nullability resolve(Parameter parameter)

Description copied from interface: NullabilityResolver

Determines the declared Nullability of the given parameter.

Specified by:

resolve in interface NullabilityResolver

Parameters:

parameter - the parameter to determine the nullability of

Returns:

the declared nullability, or Nullability.UNKNOWN when this resolver cannot tell