Process an incoming message and return the next behavior.

The returned behavior can in addition to normal behaviors be one of the canned special objects:

* returning stopped will terminate this Behavior * returning same designates to reuse the current Behavior * returning unhandled keeps the same Behavior and signals that the message was not yet handled

Code calling this method should use Behavior$ canonicalize to replace the special objects with real Behaviors.

Process an incoming Signal and return the next behavior. This means that all lifecycle hooks, ReceiveTimeout, Terminated and Failed messages can initiate a behavior change.

The returned behavior can in addition to normal behaviors be one of the canned special objects:

* returning stopped will terminate this Behavior * returning same designates to reuse the current Behavior * returning unhandled keeps the same Behavior and signals that the message was not yet handled

Code calling this method should use Behavior$ canonicalize to replace the special objects with real Behaviors.

Narrow the type of this Behavior, which is always a safe operation. This method is necessary to implement the contravariant nature of Behavior (which cannot be expressed directly due to type inference problems).

Transform the incoming messages by placing a funnel in front of the wrapped Behavior: the supplied PartialFunction decides which message to pull in (those that it is defined at) and may transform the incoming message to place them into the wrapped Behavior’s type hierarchy. Signals are not transformed.

Example:

val b: Behavior[Number] =
  Behaviors
    .receive[String] { (ctx, msg) =>
      println(msg)
      Behaviors.same
    }
    .transformMessages[Number] {
      case b: BigDecimal => s"BigDecimal($b)"
      case i: BigInt     => s"BigInteger($i)"
      // all other kinds of Number will be `unhandled`
    }

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.