Package akka.actor.typed

Class BehaviorInterceptor<Outer,Inner>

java.lang.Object

akka.actor.typed.BehaviorInterceptor<Outer,Inner>

Type Parameters:

Outer - The outer message type – the type of messages the intercepting behavior will accept

Inner - The inner message type - the type of message the wrapped behavior accepts

Direct Known Subclasses:

AbstractSupervisor, BehaviorSignalInterceptor

public abstract class BehaviorInterceptor<Outer,Inner>
extends java.lang.Object

A behavior interceptor allows for intercepting message and signal reception and perform arbitrary logic - transform, filter, send to a side channel etc. It is the core API for decoration of behaviors.

The BehaviorInterceptor API is considered a low level tool for building other features and shouldn't be used for "normal" application logic. Several built-in intercepting behaviors are provided through factories in the respective Behaviors.

If the interceptor does keep mutable state care must be taken to create a new instance from the factory function of Behaviors.intercept so that a new instance is created per spawned actor rather than shared among actor instance.

param: interceptMessageClass Ensures that the interceptor will only receive O message types. If the message is not of this class or a subclass thereof (e.g. a private protocol) will bypass the interceptor and be continue to the inner behavior untouched.

See Also:

BehaviorSignalInterceptor

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
static interface	BehaviorInterceptor.PreStartTarget<T>	Abstraction of passing the on further in the behavior stack in aroundStart(akka.actor.typed.TypedActorContext<Outer>, akka.actor.typed.BehaviorInterceptor.PreStartTarget<Inner>).
static interface	BehaviorInterceptor.ReceiveTarget<T>	Abstraction of passing the message on further in the behavior stack in aroundReceive(akka.actor.typed.TypedActorContext<Outer>, Outer, akka.actor.typed.BehaviorInterceptor.ReceiveTarget<Inner>).
static interface	BehaviorInterceptor.SignalTarget<T>	Abstraction of passing the signal on further in the behavior stack in aroundReceive(akka.actor.typed.TypedActorContext<Outer>, Outer, akka.actor.typed.BehaviorInterceptor.ReceiveTarget<Inner>).

Constructor Summary

Constructors

Constructor	Description
BehaviorInterceptor(java.lang.Class<Outer> interceptMessageClass)
BehaviorInterceptor(scala.reflect.ClassTag<Outer> interceptMessageClassTag)	Scala API: The ClassTag for Outer ensures that only messages of this class or a subclass thereof will be intercepted.

Method Summary

Modifier and Type	Method	Description
abstract Behavior<Inner>	aroundReceive(TypedActorContext<Outer> ctx, Outer msg, BehaviorInterceptor.ReceiveTarget<Inner> target)	Intercept a message sent to the running actor.
Behavior<Inner>	aroundSignal(TypedActorContext<Outer> ctx, Signal signal, BehaviorInterceptor.SignalTarget<Inner> target)	Override to intercept a signal sent to the running actor.
Behavior<Inner>	aroundStart(TypedActorContext<Outer> ctx, BehaviorInterceptor.PreStartTarget<Inner> target)	Override to intercept actor startup.
java.lang.Class<Outer>	interceptMessageClass()
boolean	isSame(BehaviorInterceptor<java.lang.Object,java.lang.Object> other)

Methods inherited from class java.lang.Object

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

Constructor Detail

BehaviorInterceptor

public BehaviorInterceptor(java.lang.Class<Outer> interceptMessageClass)

BehaviorInterceptor

public BehaviorInterceptor(scala.reflect.ClassTag<Outer> interceptMessageClassTag)

Scala API: The ClassTag for Outer ensures that only messages of this class or a subclass thereof will be intercepted. Other message types (e.g. a private protocol) will bypass the interceptor and be continue to the inner behavior untouched.

Method Detail

interceptMessageClass

public java.lang.Class<Outer> interceptMessageClass()

aroundStart

public Behavior<Inner> aroundStart(TypedActorContext<Outer> ctx,
                                   BehaviorInterceptor.PreStartTarget<Inner> target)

Override to intercept actor startup. To trigger startup of the next behavior in the stack, call target.start().

Returns:

The returned behavior will be the "started" behavior of the actor used to accept the next message or signal.

aroundReceive

public abstract Behavior<Inner> aroundReceive(TypedActorContext<Outer> ctx,
                                              Outer msg,
                                              BehaviorInterceptor.ReceiveTarget<Inner> target)

Intercept a message sent to the running actor. Pass the message on to the next behavior in the stack by passing it to target.apply, return Behaviors.same without invoking target to filter out the message.

Returns:

The behavior for next message or signal

aroundSignal

public Behavior<Inner> aroundSignal(TypedActorContext<Outer> ctx,
                                    Signal signal,
                                    BehaviorInterceptor.SignalTarget<Inner> target)

Override to intercept a signal sent to the running actor. Pass the signal on to the next behavior in the stack by passing it to target.apply.

Returns:

The behavior for next message or signal

See Also:

BehaviorSignalInterceptor

isSame

public boolean isSame(BehaviorInterceptor<java.lang.Object,java.lang.Object> other)

Returns:

true if this behavior logically the same as another behavior interceptor and can therefore be eliminated (to avoid building infinitely growing stacks of behaviors)? Default implementation is based on instance equality. Override to provide use case specific logic.