Class Throttler

  extended by akka.contrib.throttle.Throttler

public class Throttler
extends java.lang.Object

== Throttling == A throttler is an actor that is defined through a target actor and a rate (of type Throttler.Rate). You set or change the target and rate at any time through the SetTarget(target) and SetRate(rate) messages, respectively. When you send the throttler any other message msg, it will put the message msg into an internal queue and eventually send all queued messages to the target, at a speed that respects the given rate. If no target is currently defined then the messages will be queued and will be delivered as soon as a target gets set.

A throttler understands actor messages of type Throttler.SetTarget, Throttler.SetRate, in addition to any other messages, which the throttler will consider as messages to be sent to the target.

== Transparency == Notice that the throttler forwards messages, i.e., the target will see the original message sender (and not the throttler) as the sender of the message.

== Persistence == Throttlers usually use an internal queue to keep the messages that need to be sent to the target. You therefore cannot rely on the throttler's inbox size in order to learn how much messages are outstanding.

It is left to the implementation whether the internal queue is persisted over application restarts or actor failure.

== Processing messages == The target should process messages as fast as possible. If the target requires substantial time to process messages, it should distribute its work to other actors (using for example something like a BalancingDispatcher), otherwise the resulting system will always work below the threshold rate.

Example: Suppose the throttler has a rate of 3msg/s and the target requires 1s to process a message. This system will only process messages at a rate of 1msg/s: the target will receive messages at at most 3msg/s but as it handles them synchronously and each of them takes 1s, its inbox will grow and grow. In such a situation, the target should distribute its messages to a set of worker actors so that individual messages can be handled in parallel.

See Also:
TimerBasedThrottler, Throttler.Rate

Nested Class Summary
static class Throttler.Rate
          A rate used for throttling.
static class Throttler.Rate$
static class Throttler.RateInt
          Helper for some syntactic sugar.
static class Throttler.RateInt$
static class Throttler.SetRate
          Set the rate of a throttler.
static class Throttler.SetRate$
static class Throttler.SetTarget
          Set the target of a throttler.
static class Throttler.SetTarget$
Constructor Summary
Method Summary
Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail


public Throttler()