Module dk.cloudcreate.essentials.components.eventsourced.aggregates

Package dk.cloudcreate.essentials.components.eventsourced.aggregates.stateful.classic.state

Class AggregateRootWithState<ID,EVENT_TYPE extends Event<ID>,STATE extends AggregateState<ID,EVENT_TYPE>,AGGREGATE_TYPE extends AggregateRootWithState<ID,EVENT_TYPE,STATE,AGGREGATE_TYPE>>

java.lang.Object

dk.cloudcreate.essentials.components.eventsourced.aggregates.stateful.classic.AggregateRoot<ID,EVENT_TYPE,AGGREGATE_TYPE>

dk.cloudcreate.essentials.components.eventsourced.aggregates.stateful.classic.state.AggregateRootWithState<ID,EVENT_TYPE,STATE,AGGREGATE_TYPE>

Type Parameters:

ID - the aggregate id type

EVENT_TYPE - the type of event

AGGREGATE_TYPE - the aggregate self type (i.e. your concrete aggregate type)

STATE - the aggregate state type (i.e. your concrete aggregate state)

All Implemented Interfaces:

Aggregate<ID,AGGREGATE_TYPE>, StatefulAggregate<ID,EVENT_TYPE,AGGREGATE_TYPE>

public abstract class AggregateRootWithState<ID,EVENT_TYPE extends Event<ID>,STATE extends AggregateState<ID,EVENT_TYPE>,AGGREGATE_TYPE extends AggregateRootWithState<ID,EVENT_TYPE,STATE,AGGREGATE_TYPE>>
extends AggregateRoot<ID,EVENT_TYPE,AGGREGATE_TYPE>

Variant of the AggregateRoot pattern where the aggregate's state and all EventHandler annotated methods are placed within the concrete AggregateState object.
When the AggregateRootWithState is combined with AggregateState, then the AggregateRootWithState will contain the command methods and the AggregateState contains the state fields and the EventHandler annotated methods.

Field Summary

Fields

Modifier and Type	Field	Description
protected STATE	state

Constructor Summary

Constructors

Constructor	Description
AggregateRootWithState()

Method Summary

Modifier and Type	Method	Description
ID	aggregateId()	The id of the aggregate (aka.
protected void	apply(EVENT_TYPE event)	Apply a new non persisted/uncommitted Event to this aggregate instance. If it is the very FIRST Event that is being applied then Event.aggregateId() MUST return the ID of the aggregate the event relates to Every consecutive Event applied will have its Event.aggregateId(Object) method called IF it doesn't already have a value.
dk.cloudcreate.essentials.components.eventsourced.eventstore.postgresql.types.EventOrder	eventOrderOfLastAppliedEvent()	Get the of the last {}@link Event that was applied to the AggregateRoot (either using AggregateRoot.rehydrate(AggregateEventStream)/AggregateRoot.rehydrate(Stream) or using AggregateRoot.apply(Event)
dk.cloudcreate.essentials.components.eventsourced.eventstore.postgresql.types.EventOrder	eventOrderOfLastRehydratedEvent()	Get the eventOrder of the last event during aggregate hydration (using the Aggregate.rehydrate(AggregateEventStream) method)
EventsToPersist<ID,EVENT_TYPE>	getUncommittedChanges()	The the events that have been applied to this aggregate instance but not yet persisted to the underlying EventStore
protected void	initialize()	Override this method to initialize the state variable in case the resolveStateImplementationClass() doesn't fit the requirements
void	markChangesAsCommitted()	Resets the AggregateRoot.getUncommittedChanges() - effectively marking them as having been persisted and committed to the underlying EventStore
AGGREGATE_TYPE	rehydrate(Stream<EVENT_TYPE> previousEvents)	Effectively performs a leftFold over all the previous events related to this aggregate instance
protected Class<AggregateState>	resolveStateImplementationClass()	Override this method to provide a non reflection based look up of the Type Argument provided to the AggregateRootWithState class

Methods inherited from class dk.cloudcreate.essentials.components.eventsourced.aggregates.stateful.classic.AggregateRoot

applyEventToTheAggregateState, hasBeenRehydrated, isRehydrating, rehydrate

Methods inherited from class java.lang.Object

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

Field Details

state

protected STATE extends AggregateState<ID,EVENT_TYPE> state

Constructor Details

AggregateRootWithState

public AggregateRootWithState()

Method Details

initialize

protected void initialize()

Override this method to initialize the state variable in case the resolveStateImplementationClass() doesn't fit the requirements

Overrides:

initialize in class AggregateRoot<ID,EVENT_TYPE extends Event<ID>,AGGREGATE_TYPE extends AggregateRootWithState<ID,EVENT_TYPE,STATE,AGGREGATE_TYPE>>

rehydrate

public AGGREGATE_TYPE rehydrate(Stream<EVENT_TYPE> previousEvents)

Description copied from class: AggregateRoot

Effectively performs a leftFold over all the previous events related to this aggregate instance

Overrides:

rehydrate in class AggregateRoot<ID,EVENT_TYPE extends Event<ID>,AGGREGATE_TYPE extends AggregateRootWithState<ID,EVENT_TYPE,STATE,AGGREGATE_TYPE>>

Parameters:

previousEvents - the previous events related to this aggregate instance, aka. the aggregates history

Returns:

the same aggregate instance (self)

eventOrderOfLastRehydratedEvent

public dk.cloudcreate.essentials.components.eventsourced.eventstore.postgresql.types.EventOrder eventOrderOfLastRehydratedEvent()

Description copied from interface: Aggregate

Get the eventOrder of the last event during aggregate hydration (using the Aggregate.rehydrate(AggregateEventStream) method)

Specified by:

eventOrderOfLastRehydratedEvent in interface Aggregate<ID,EVENT_TYPE extends Event<ID>>

Overrides:

eventOrderOfLastRehydratedEvent in class AggregateRoot<ID,EVENT_TYPE extends Event<ID>,AGGREGATE_TYPE extends AggregateRootWithState<ID,EVENT_TYPE,STATE,AGGREGATE_TYPE>>

Returns:

the event order of the last applied Event or EventOrder.NO_EVENTS_PREVIOUSLY_PERSISTED in case no events has ever been applied to the aggregate

apply

protected void apply(EVENT_TYPE event)

Description copied from class: AggregateRoot

Apply a new non persisted/uncommitted Event to this aggregate instance.
If it is the very FIRST Event that is being applied then Event.aggregateId() MUST return the ID of the aggregate the event relates to
Every consecutive Event applied will have its Event.aggregateId(Object) method called IF it doesn't already have a value. I.e. you can be lazy and skip setting the aggregate id on the Event if you don't want to.

The AggregateRoot automatically keeps track of the Event.eventOrder() value and will set it for you and ensure that it's growing consecutively.

Overrides:

apply in class AggregateRoot<ID,EVENT_TYPE extends Event<ID>,AGGREGATE_TYPE extends AggregateRootWithState<ID,EVENT_TYPE,STATE,AGGREGATE_TYPE>>

Parameters:

event - the event to apply

aggregateId

public ID aggregateId()

Description copied from interface: Aggregate

The id of the aggregate (aka. the stream-id)

Specified by:

aggregateId in interface Aggregate<ID,EVENT_TYPE extends Event<ID>>

Overrides:

aggregateId in class AggregateRoot<ID,EVENT_TYPE extends Event<ID>,AGGREGATE_TYPE extends AggregateRootWithState<ID,EVENT_TYPE,STATE,AGGREGATE_TYPE>>

eventOrderOfLastAppliedEvent

public dk.cloudcreate.essentials.components.eventsourced.eventstore.postgresql.types.EventOrder eventOrderOfLastAppliedEvent()

Description copied from class: AggregateRoot

Get the of the last {}@link Event that was applied to the AggregateRoot (either using AggregateRoot.rehydrate(AggregateEventStream)/AggregateRoot.rehydrate(Stream) or using AggregateRoot.apply(Event)

Overrides:

eventOrderOfLastAppliedEvent in class AggregateRoot<ID,EVENT_TYPE extends Event<ID>,AGGREGATE_TYPE extends AggregateRootWithState<ID,EVENT_TYPE,STATE,AGGREGATE_TYPE>>

Returns:

the event order of the last applied Event or EventOrder.NO_EVENTS_PREVIOUSLY_PERSISTED in case no events has ever been applied to the aggregate

getUncommittedChanges

public EventsToPersist<ID,EVENT_TYPE> getUncommittedChanges()

Description copied from class: AggregateRoot

The the events that have been applied to this aggregate instance but not yet persisted to the underlying EventStore

Specified by:

getUncommittedChanges in interface StatefulAggregate<ID,EVENT_TYPE extends Event<ID>,STATE extends AggregateState<ID,EVENT_TYPE>>

Overrides:

getUncommittedChanges in class AggregateRoot<ID,EVENT_TYPE extends Event<ID>,AGGREGATE_TYPE extends AggregateRootWithState<ID,EVENT_TYPE,STATE,AGGREGATE_TYPE>>

Returns:

the changes to the aggregate

markChangesAsCommitted

public void markChangesAsCommitted()

Description copied from class: AggregateRoot

Resets the AggregateRoot.getUncommittedChanges() - effectively marking them as having been persisted and committed to the underlying EventStore

Specified by:

markChangesAsCommitted in interface StatefulAggregate<ID,EVENT_TYPE extends Event<ID>,STATE extends AggregateState<ID,EVENT_TYPE>>

Overrides:

markChangesAsCommitted in class AggregateRoot<ID,EVENT_TYPE extends Event<ID>,AGGREGATE_TYPE extends AggregateRootWithState<ID,EVENT_TYPE,STATE,AGGREGATE_TYPE>>

resolveStateImplementationClass

protected Class<AggregateState> resolveStateImplementationClass()

Override this method to provide a non reflection based look up of the Type Argument provided to the AggregateRootWithState class

Returns:

the AggregateState implementation to use for the state instance