Class LazyAggregateRoot<T>

java.lang.Object

io.fluxzero.sdk.modeling.LazyAggregateRoot<T>

Type Parameters:

T - The type of the aggregate's value.

All Implemented Interfaces:

AggregateRoot<T>, Entity<T>

public class LazyAggregateRoot<T>
extends Object
implements AggregateRoot<T>

A lazily-loaded implementation of AggregateRoot that defers deserialization and event application until the entity value is explicitly accessed.

This implementation is typically used as a historical previous reference in ImmutableAggregateRoot when the aggregate's Aggregate.cachingDepth() has been exceeded. In such cases, only the checkpointed state is retained in memory, and the full entity state is reconstructed by replaying events from the most recent checkpoint.

LazyAggregateRoot is read-only and will throw UnsupportedOperationException for any attempt to apply updates or modify the state. It is solely intended for retrieving past states in an efficient and memory-conscious way.

Event replay occurs on demand via the get() method, which reconstructs the aggregate state by re-applying all events from the last known checkpoint until the desired sequence number or event id is reached.

See Also:

• ImmutableAggregateRoot.asPrevious(long)

Field Summary

Fields inherited from interface Entity

AGGREGATE_ID_METADATA_KEY, AGGREGATE_SN_METADATA_KEY, AGGREGATE_TYPE_METADATA_KEY, applying, loading

Constructor Summary

Constructors

Modifier	Constructor	Description
protected	LazyAggregateRoot(ImmutableAggregateRoot<T> delegate)

Method Summary

Modifier and Type	Method	Description
Collection<?>	aliases()	Retrieves a collection of aliases associated with this entity.
Entity<T>	apply(Message eventMessage)	Applies the given message to the entity.
<E extends Exception> Entity<T>	assertLegal(Object update)	Verifies that the provided update is legal given the current state of the aggregate.
Entity<T>	commit()	Commits the current state of the entity, persisting any changes made to it.
Collection<? extends Entity<?>>	entities()	Retrieves child entities of this entity.
static <T> LazyAggregateRoot<T>	from(ImmutableAggregateRoot<T> delegate)
T	get()	Retrieves the current instance of the entity.
protected Entity<T>	getLastCheckpoint()
Object	id()	Retrieves the unique identifier of the entity.
String	idProperty()	Retrieves the name of the property that serves as the unique identifier for the entity.
String	lastEventId()	Retrieves the identifier of the last event applied to the entity hierarchy.
Long	lastEventIndex()	Retrieves the index of the last event applied to this entity hierarchy.
Entity<T>	previous()	Retrieves the previous version of this entity.
long	sequenceNumber()	Retrieves the sequence number of the current entity.
Instant	timestamp()	Retrieves the timestamp of the entity.
Class<T>	type()	Retrieves the type of the entity.
Entity<T>	update(UnaryOperator<T> function)	Updates the current entity's value using the specified unary operator and returns a new entity containing the updated value.
Entity<T>	withEventIndex(Long index, String messageId)	Updates the event index and message ID of the entity and returns the updated version of the entity.
Entity<T>	withSequenceNumber(long sequenceNumber)	Returns an updated entity based on this with the specified sequence number.
Entity<T>	withType(Class<T> type)	Sets the type of the entity to the specified class and returns the updated entity.

Methods inherited from class Object

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

Methods inherited from interface AggregateRoot

parent

Methods inherited from interface Entity

allEntities, ancestors, ancestorValue, apply, apply, apply, apply, apply, assertAndApply, assertAndApply, assertAndApply, assertAndApply, associations, depth, dissociations, getEntity, highestEventIndex, ifPresent, isEmpty, isPresent, isRoot, mapIfPresent, playBackToCondition, playBackToEvent, possibleTargets, relationships, root, rootAnnotation

Constructor Details

LazyAggregateRoot

protected LazyAggregateRoot(ImmutableAggregateRoot<T> delegate)

Method Details

from

public static <T> LazyAggregateRoot<T> from(ImmutableAggregateRoot<T> delegate)

withEventIndex

public Entity<T> withEventIndex(Long index,
 String messageId)

Description copied from interface: Entity

Updates the event index and message ID of the entity and returns the updated version of the entity.

Specified by:

withEventIndex in interface AggregateRoot<T>

Specified by:

withEventIndex in interface Entity<T>

Parameters:

index - the event index to set for the root entity

messageId - the message ID associated with the event

Returns:

the updated entity corresponding to the current entity's ID and type, or null if no such entity can be found

sequenceNumber

public long sequenceNumber()

Description copied from interface: Entity

Retrieves the sequence number of the current entity.

Specified by:

sequenceNumber in interface AggregateRoot<T>

Specified by:

sequenceNumber in interface Entity<T>

Returns:

the sequence number of the root entity

timestamp

public Instant timestamp()

Description copied from interface: Entity

Retrieves the timestamp of the entity.

Specified by:

timestamp in interface AggregateRoot<T>

Specified by:

timestamp in interface Entity<T>

Returns:

the timestamp as an Instant obtained from the root entity

previous

public Entity<T> previous()

Description copied from interface: Entity

Retrieves the previous version of this entity.

Specified by:

previous in interface AggregateRoot<T>

Specified by:

previous in interface Entity<T>

Returns:

the previous state of the entity, or null if this is the first known version

get

public T get()

Description copied from interface: Entity

Retrieves the current instance of the entity.

Specified by:

get in interface Entity<T>

Returns:

the current instance of the entity or null if not initialized

getLastCheckpoint

protected Entity<T> getLastCheckpoint()

aliases

public Collection<?> aliases()

Description copied from interface: Entity

Retrieves a collection of aliases associated with this entity.

Specified by:

aliases in interface Entity<T>

Returns:

a collection containing aliases of this entity, or an empty collection if no aliases are present

entities

public Collection<? extends Entity<?>> entities()

Description copied from interface: Entity

Retrieves child entities of this entity.

Specified by:

entities in interface Entity<T>

Returns:

a collection containing child entities.

id

public Object id()

Description copied from interface: Entity

Retrieves the unique identifier of the entity.

Specified by:

id in interface Entity<T>

Returns:

the unique identifier of the entity, or null if this entity has not been initialized yet

type

public Class<T> type()

Description copied from interface: Entity

Retrieves the type of the entity.

Specified by:

type in interface Entity<T>

Returns:

the class type of the entity, or null if the type has not been defined

idProperty

public String idProperty()

Description copied from interface: Entity

Retrieves the name of the property that serves as the unique identifier for the entity.

Specified by:

idProperty in interface Entity<T>

Returns:

the name of the identification property as a string

lastEventId

public String lastEventId()

Description copied from interface: Entity

Retrieves the identifier of the last event applied to the entity hierarchy.

Specified by:

lastEventId in interface AggregateRoot<T>

Specified by:

lastEventId in interface Entity<T>

Returns:

the identifier of the last event as a string, or null if no events have been recorded in the entity's aggregate

lastEventIndex

public Long lastEventIndex()

Description copied from interface: Entity

Retrieves the index of the last event applied to this entity hierarchy.

Specified by:

lastEventIndex in interface AggregateRoot<T>

Specified by:

lastEventIndex in interface Entity<T>

Returns:

the index of the last event as a Long, or null if no events have been recorded for the entity's aggregate

update

public Entity<T> update(UnaryOperator<T> function)

Description copied from interface: Entity

Updates the current entity's value using the specified unary operator and returns a new entity containing the updated value.

Specified by:

update in interface Entity<T>

Parameters:

function - the unary operator to apply to the current entity's value

Returns:

a new entity containing the updated value after applying the function

apply

public Entity<T> apply(Message eventMessage)

Description copied from interface: Entity

Applies the given message to the entity.

Specified by:

apply in interface Entity<T>

Parameters:

eventMessage - the message representing the event to be applied

Returns:

the updated or newly created Entity of type T

commit

public Entity<T> commit()

Description copied from interface: Entity

Commits the current state of the entity, persisting any changes made to it. This method ensures that the modifications are saved. Typically, it is unnecessary to invoke this manually as it is automatically invoked after the current handler or consumer batch has completed.

Specified by:

commit in interface Entity<T>

Returns:

The updated entity after the commit operation is successfully completed.

withType

public Entity<T> withType(Class<T> type)

Description copied from interface: Entity

Sets the type of the entity to the specified class and returns the updated entity.

Specified by:

withType in interface Entity<T>

Parameters:

type - the class representing the type to be set for the entity

Returns:

the updated entity with the specified type

withSequenceNumber

public Entity<T> withSequenceNumber(long sequenceNumber)

Description copied from interface: Entity

Returns an updated entity based on this with the specified sequence number.

Specified by:

withSequenceNumber in interface AggregateRoot<T>

Specified by:

withSequenceNumber in interface Entity<T>

Parameters:

sequenceNumber - the sequence number to assign to the entity

Returns:

the updated entity with the specified sequence number, or null if the entity could not be found in the entity hierarchy

assertLegal

public <E extends Exception> Entity<T> assertLegal(Object update)
                                            throws E

Description copied from interface: Entity

Verifies that the provided update is legal given the current state of the aggregate. If so, the entity is returned; otherwise, it throws an appropriate exception.

Specified by:

assertLegal in interface Entity<T>

Type Parameters:

E - the type of exception expected if the update is not legal

Parameters:

update - the update to be validated for compliance with the required rules

Returns:

the entity if the update is legal

Throws:

E - if the update fails to meet legal requirements