io.spine.server.aggregate

Class AggregatePart<I,S extends io.spine.base.EntityState,B extends io.spine.protobuf.ValidatingBuilder<S>,R extends AggregateRoot<I>>

java.lang.Object

io.spine.server.entity.AbstractEntity<I,S>

io.spine.server.entity.TransactionalEntity<I,S,B>

io.spine.server.command.CommandHandlingEntity<I,S,B>

io.spine.server.aggregate.Aggregate<I,S,B>

io.spine.server.aggregate.AggregatePart<I,S,B,R>

Type Parameters:

I - the type for IDs of this class of aggregates

S - the type of the state held by the aggregate part

B - the type of the aggregate part state builder

R - the type of the aggregate root

All Implemented Interfaces:

CommandHandler, CommandReceiver, Entity<I,S>, WithLifecycle, EventReactor, EventReceiver, EventProducer, HandlerLifecycle

@Experimental
public abstract class AggregatePart<I,S extends io.spine.base.EntityState,B extends io.spine.protobuf.ValidatingBuilder<S>,R extends AggregateRoot<I>>
extends Aggregate<I,S,B>

A part of a larger aggregate.

Some business logic objects may be big enough. If not all parts of such a business object need to be preserved at the same time as business logic invariants, such an object can be split into several parts.

Each such part would:

• be a class derived from AggregatePart
• have the same aggregate ID as other parts belonging to the same business object
• have own state defined as a Protobuf message
• managed by a separate repository class derived from AggregateRepository

To access parts of the aggregate, AggregateRoot should be used.

If your business logic cannot be split into parts, it can be modified separately. Consider extending Aggregate instead of several AggregateParts.

See Also:

Aggregate

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static class	AggregatePart.GenericParameter Enumeration of generic type parameters of this class.

Constructor Summary

Constructors

Modifier	Constructor and Description
protected	AggregatePart(R root) Creates a new instance of the aggregate part.

Method Summary

Modifier and Type	Method and Description
protected <P extends io.spine.base.EntityState> P	partState(java.lang.Class<P> partStateClass) Obtains a state of another AggregatePart by its class.
protected AggregatePartClass<?>	thisClass() Obtains model class for this aggregate part.

Methods inherited from class io.spine.server.aggregate.Aggregate

builder, clearRecentHistory, dispatchCommand, historyBackward, historyContains, missingTxMessage, play, recentHistory, versionNumber

Methods inherited from class io.spine.server.command.CommandHandlingEntity

expectedDefault, expectedEmpty, expectedNotDefault, expectedNotDefault, expectedNotEmpty, producerId, unexpectedValue, unexpectedValue

Methods inherited from class io.spine.server.entity.TransactionalEntity

getLifecycleFlags, remember, setArchived, setDeleted, setInitialState, tx

Methods inherited from class io.spine.server.entity.AbstractEntity

afterInvoke, at, beforeInvoke, checkEntityState, checkNotArchived, checkNotDeleted, defaultState, equals, hashCode, id, idAsString, isArchived, isDeleted, lifecycleFlagsChanged, state, toString, version, whenModified

Methods inherited from class java.lang.Object

clone, finalize, getClass, notify, notifyAll, wait, wait, wait

Methods inherited from interface io.spine.server.EventProducer

nothing, producerId, version

Methods inherited from interface io.spine.server.entity.WithLifecycle

isActive, lifecycleFlags

Constructor Detail

AggregatePart

protected AggregatePart(R root)

Creates a new instance of the aggregate part.

Parameters:

root - a root of the aggregate to which this part belongs

Method Detail

thisClass

protected AggregatePartClass<?> thisClass()

Obtains model class for this aggregate part.

Overrides:

thisClass in class Aggregate<I,S extends io.spine.base.EntityState,B extends io.spine.protobuf.ValidatingBuilder<S>>

partState

protected <P extends io.spine.base.EntityState> P partState(java.lang.Class<P> partStateClass)

Obtains a state of another AggregatePart by its class.

Type Parameters:

P - the type of the part state

Parameters:

partStateClass - the class of the state of the part

Returns:

the state of the part or a default state if the state was not found

Throws:

java.lang.IllegalStateException - if a repository was not found, or the ID type of the part state does not match the ID type of the root