com.lightbend.lagom.javadsl.persistence

Class PersistentEntity.BehaviorBuilder

Object

com.lightbend.lagom.javadsl.persistence.PersistentEntity.BehaviorBuilder

Enclosing class:

PersistentEntity<Command,Event,State>

public abstract class PersistentEntity.BehaviorBuilder
extends Object

Mutable builder that is used for defining the event and command handlers. Use build() to create the immutable PersistentEntity.Behavior.

Constructor Summary

Constructors

Constructor and Description
BehaviorBuilder()

Method Summary

Modifier and Type	Method and Description
abstract PersistentEntity.Behavior	build() Construct the corresponding immutable Behavior.
abstract State	getState()
abstract void	removeCommandHandler(Class<? extends Command> commandClass) Remove a command handler for a given command class.
abstract void	removeEventHandler(Class<? extends Event> eventClass) Remove an event handler for a given event class.
abstract <R,A extends Command> void	setCommandHandler(Class<A> commandClass, BiFunction<A,PersistentEntity.CommandContext<R>,PersistentEntity.Persist<? extends Event>> handler) Register a command handler for a given command class.
abstract <A extends Event> void	setEventHandler(Class<A> eventClass, Function<A,State> handler) Register an event handler for a given event class.
abstract <A extends Event> void	setEventHandlerChangingBehavior(Class<A> eventClass, Function<A,PersistentEntity.Behavior> handler) Register an event handler that is updating the behavior for a given event class.
abstract <R,A extends Command> void	setReadOnlyCommandHandler(Class<A> commandClass, BiConsumer<A,PersistentEntity.ReadOnlyCommandContext<R>> handler) Register a read-only command handler for a given command class.
abstract void	setState(State state)

Methods inherited from class Object

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

Constructor Detail

BehaviorBuilder

public BehaviorBuilder()

Method Detail

build

public abstract PersistentEntity.Behavior build()

Construct the corresponding immutable Behavior.

getState

public abstract State getState()

removeCommandHandler

public abstract void removeCommandHandler(Class<? extends Command> commandClass)

Remove a command handler for a given command class.

removeEventHandler

public abstract void removeEventHandler(Class<? extends Event> eventClass)

Remove an event handler for a given event class.

setCommandHandler

public abstract <R,A extends Command> void setCommandHandler(Class<A> commandClass,
                                                             BiFunction<A,PersistentEntity.CommandContext<R>,PersistentEntity.Persist<? extends Event>> handler)

Register a command handler for a given command class.

The handler function is supposed to return a Persist directive that defines what event or events, if any, to persist. Use the thenPersist, thenPersistAll or done methods of the context that is passed to the handler function to create the Persist directive.

After persisting an event external side effects can be performed in the afterPersist function that can be defined when creating the Persist directive. A typical side effect is to reply to the request to confirm that it was performed successfully. Replies are sent with the reply method of the context that is passed to the command handler function.

The handler function may validate the incoming command and reject it by sending a reply and returning ctx.done().

Invoking this method a second time for the same commandClass will override the existing handler.

setEventHandler

public abstract <A extends Event> void setEventHandler(Class<A> eventClass,
                                                       Function<A,State> handler)

Register an event handler for a given event class. The handler function is supposed to return the new state after applying the event to the current state. Current state can be accessed with the state method of the PersistentEntity.

Invoking this method a second time for the same eventClass will override the existing handler.

setEventHandlerChangingBehavior

public abstract <A extends Event> void setEventHandlerChangingBehavior(Class<A> eventClass,
                                                                       Function<A,PersistentEntity.Behavior> handler)

Register an event handler that is updating the behavior for a given event class. The handler function is supposed to return the new behavior after applying the event to the current state. Current behavior can be accessed with the behavior method of the PersistentEntity.

Invoking this method a second time for the same eventClass will override the existing handler.

setReadOnlyCommandHandler

public abstract <R,A extends Command> void setReadOnlyCommandHandler(Class<A> commandClass,
                                                                     BiConsumer<A,PersistentEntity.ReadOnlyCommandContext<R>> handler)

Register a read-only command handler for a given command class. A read-only command handler does not persist events (i.e. it does not change state) but it may perform side effects, such as replying to the request. Replies are sent with the reply method of the context that is passed to the command handler function.

Invoking this method a second time for the same commandClass will override the existing handler.

setState

public abstract void setState(State state)