Package org.axonframework.deadline

Class AggregateDeadlineCommandTranslator

java.lang.Object

org.axonframework.deadline.AggregateDeadlineCommandTranslator

All Implemented Interfaces:

ScopeAware

@Internal
public class AggregateDeadlineCommandTranslator
extends Object
implements ScopeAware

Translates a fired DeadlineMessage scoped to an AggregateScopeDescriptor into a command, dispatched through a CommandGateway.

Implements ScopeAware so it can be reached through a ScopeAwareProvider the same way a Saga manager is. Its send(Message, ProcessingContext, ScopeDescriptor) dispatches the deadline's payload and metadata as a command, and writes the AggregateScopeDescriptor's identifier into the dispatched command's metadata under "scope-descriptor-based-entity-identifier". AggregateDeadlineEntityIdResolverConfigurationEnhancer registers the resolver that reads this metadata entry as the application-wide default, used whenever the command's payload carries no @TargetEntityId.

A deadline scheduled without a payload carries null as its Message.payload(). Since a null payload cannot name the command to dispatch, this translator falls back to the deadline's DeadlineMessage.getDeadlineName() in that case, dispatched as both the command's name and its payload, so the migrated handler becomes @CommandHandler(commandName = "<deadlineName>") void handle(String command, ...).

Constructed and registered by the AggregateDeadlineCommandTranslatorConfigurationEnhancer.

Since:

5.4.0

Author:

Steven van Beelen

See Also:

• AggregateDeadlineCommandTranslatorConfigurationEnhancer
• AggregateDeadlineEntityIdResolverConfigurationEnhancer
• AggregateDeadlineEntityIdResolverDefinition

Constructor Summary

Constructors

Constructor	Description
AggregateDeadlineCommandTranslator(CommandGateway commandGateway)	Initializes an AggregateDeadlineCommandTranslator, dispatching translated commands through the given commandGateway.

Method Summary

Modifier and Type	Method	Description
boolean	canResolve(ScopeDescriptor scopeDescription)	Check whether this implementation can resolve a Scope object based on the provided scopeDescription.
void	send(Message message, ProcessingContext context, ScopeDescriptor scopeDescription)	Send a Message to a Scope which is described by the given scopeDescription.

Methods inherited from class java.lang.Object

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

Constructor Details

AggregateDeadlineCommandTranslator

public AggregateDeadlineCommandTranslator(CommandGateway commandGateway)

Initializes an AggregateDeadlineCommandTranslator, dispatching translated commands through the given commandGateway.

Parameters:

commandGateway - the CommandGateway to dispatch a fired aggregate deadline's command through

Method Details

canResolve

public boolean canResolve(ScopeDescriptor scopeDescription)

Check whether this implementation can resolve a Scope object based on the provided scopeDescription. Will return true in case it should be able to resolve the Scope and false if it cannot.

Returns true for every AggregateScopeDescriptor, regardless of the aggregate type it describes, since routing to the right entity is delegated to the dispatched command's @TargetEntityId, not resolved here.

Specified by:

canResolve in interface ScopeAware

Parameters:

scopeDescription - a ScopeDescriptor describing the Scope to be resolved

Returns:

true in case it should be able to resolve the Scope and false if it cannot

send

public void send(Message message,
 ProcessingContext context,
 ScopeDescriptor scopeDescription)
          throws Exception

Send a Message to a Scope which is described by the given scopeDescription.

Dispatches the message's payload and metadata as a command through the configured CommandGateway, passing the given context along so the command runs within the deadline's firing unit of work. Waits for the command's result with FutureUtils.joinAndUnwrap(java.util.concurrent.CompletableFuture), rethrowing a failure so the caller applies its own failure handling.

A message whose payload is an UnknownDeadlinePayload (its stored type could not be resolved) is not dispatched: this method logs a warning naming the deadline, the stored type and the aggregate scope, and returns.

A message whose payload is null is dispatched as a GenericCommandMessage named after, and carrying as its payload, DeadlineMessage.getDeadlineName(), since a null payload carries no type to derive a command name from.

The dispatched command's metadata always carries the scopeDescription's identifier under "scope-descriptor-based-entity-identifier", so the target entity can be resolved from it instead of from the payload.

Specified by:

send in interface ScopeAware

Parameters:

message - The Message to be sent to a Scope.

context - The ProcessingContext in which the message is being processed.

scopeDescription - A D extending ScopeDescriptor, describing the Scope to send the given message to.

Throws:

IllegalArgumentException - if the given message is not a DeadlineMessage, or if the given scopeDescription is not an AggregateScopeDescriptor

Exception - if sending the message failed. Might occur if the message handling process throws an exception.