org.axonframework.modelling.command

Class AnnotationCommandTargetResolver

java.lang.Object

org.axonframework.modelling.command.AnnotationCommandTargetResolver

All Implemented Interfaces:

CommandTargetResolver

public class AnnotationCommandTargetResolver
extends Object
implements CommandTargetResolver

CommandTargetResolver that uses annotations on the command to identify the methods that provide the Aggregate Identifier of the targeted Aggregate and optionally the expected version of the aggregate.

This implementation expects at least one method (without parameters) or field in the command to be annotated with TargetAggregateIdentifier. If on a method, the result of the invocation of that method will use as Aggregate Identifier. If on a field, the value held in that field is used.

Similarly, the expected aggregate version may be provided by annotating a method (without parameters) or field with TargetAggregateVersion. The return value of the method or value held in the field is used as the expected version. Note that the method must return a Long value, or a value that may be parsed as a Long.

Since:

1.2

Author:

Allard Buijze

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static class	AnnotationCommandTargetResolver.Builder Builder class to instantiate a AnnotationCommandTargetResolver.

Constructor Summary

Constructors

Modifier	Constructor and Description
	AnnotationCommandTargetResolver() Deprecated. Please use the builder().
protected	AnnotationCommandTargetResolver(AnnotationCommandTargetResolver.Builder builder) Instantiate a AnnotationCommandTargetResolver based on the fields contained in the AnnotationCommandTargetResolver.Builder.

Method Summary

Modifier and Type	Method and Description
static AnnotationCommandTargetResolver.Builder	builder() Instantiate a Builder to be able to create a AnnotationCommandTargetResolver.
VersionedAggregateIdentifier	resolveTarget(CommandMessage<?> command) Returns the Aggregate Identifier and optionally the expected version of the aggregate on which the given command should be executed.
String	toString()

Methods inherited from class java.lang.Object

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

Constructor Detail

AnnotationCommandTargetResolver

@Deprecated
public AnnotationCommandTargetResolver()

Deprecated. Please use the builder().

AnnotationCommandTargetResolver

protected AnnotationCommandTargetResolver(AnnotationCommandTargetResolver.Builder builder)

Instantiate a AnnotationCommandTargetResolver based on the fields contained in the AnnotationCommandTargetResolver.Builder.

Parameters:

builder - the AnnotationCommandTargetResolver.Builder used to instantiate a AnnotationCommandTargetResolver instance

Method Detail

builder

public static AnnotationCommandTargetResolver.Builder builder()

Instantiate a Builder to be able to create a AnnotationCommandTargetResolver.

The TargetAggregateIdentifierAnnotation is defaulted to TargetAggregateIdentifier, TargetAggregateVersionAnnotation to TargetAggregateVersion.

Returns:

a Builder to be able to create aAnnotationCommandTargetResolver

resolveTarget

public VersionedAggregateIdentifier resolveTarget(@Nonnull
                                                  CommandMessage<?> command)

Returns the Aggregate Identifier and optionally the expected version of the aggregate on which the given command should be executed.

The version may be null if no specific version is required. Furthermore, the returned VersionedAggregateIdentifier may be null entirely when the given command is targeted towards a CreationPolicy annotated command handler that (optionally) constructs a new aggregate instance.

Specified by:

resolveTarget in interface CommandTargetResolver

Parameters:

command - The command from which to extract the identifier and version.

Returns:

A VersionedAggregateIdentifier instance reflecting the aggregate to execute the command on, or null when the command is targeted towards a CreationPolicy annotated command handler that constructs a new aggregate instance.

See Also:

AggregateCreationPolicy.ALWAYS, AggregateCreationPolicy.CREATE_IF_MISSING

toString

public String toString()

Overrides:

toString in class Object