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java.lang.Object akka.routing.ConsistentHashingRouter
public class ConsistentHashingRouter
A Router that uses consistent hashing to select a connection based on the sent message.
There is 3 ways to define what data to use for the consistent hash key.
1. You can define hashMapping
/ withHashMapper
of the router to map incoming messages to their consistent hash key.
This makes the decision transparent for the sender.
2. The messages may implement ConsistentHashingRouter.ConsistentHashable
.
The key is part of the message and it's convenient to define it together
with the message definition.
3. The messages can be be wrapped in a ConsistentHashingRouter.ConsistentHashableEnvelope
to define what data to use for the consistent hash key. The sender knows
the key to use.
These ways to define the consistent hash key can be use together and at
the same time for one router. The hashMapping
is tried first.
Please note that providing both 'nrOfInstances' and 'routees' does not make logical
sense as this means that the router should both create new actors and use the 'routees'
actor(s). In this case the 'nrOfInstances' will be ignored and the 'routees' will be used.
The configuration parameter trumps the constructor arguments. This means that
if you provide either 'nrOfInstances' or 'routees' during instantiation they will
be ignored if the router is defined in the configuration file for the actor being used.
Any routees that are created by a router will be created as the router's children. The router is therefore also the children's supervisor.
The supervision strategy of the router actor can be configured with
withSupervisorStrategy(akka.actor.SupervisorStrategy)
. If no strategy is provided, routers default to
a strategy of “always escalate”. This means that errors are passed up to the
router's supervisor for handling.
The router's supervisor will treat the error as an error with the router itself. Therefore a directive to stop or restart will cause the router itself to stop or restart. The router, in turn, will cause its children to stop and restart.
Nested Class Summary | |
---|---|
static interface |
ConsistentHashingRouter.ConsistentHashable
If you don't define the hashMapping when
constructing the ConsistentHashingRouter
the messages need to implement this interface to define what
data to use for the consistent hash key. |
static class |
ConsistentHashingRouter.ConsistentHashableEnvelope
If you don't define the hashMapping when
constructing the ConsistentHashingRouter
and messages can't implement ConsistentHashingRouter.ConsistentHashable
themselves they can we wrapped by this envelope instead. |
static class |
ConsistentHashingRouter.ConsistentHashableEnvelope$
|
static interface |
ConsistentHashingRouter.ConsistentHashMapper
JAVA API Mapping from message to the data to use for the consistent hash key. |
static class |
ConsistentHashingRouter.emptyConsistentHashMapping$
|
Constructor Summary | |
---|---|
ConsistentHashingRouter(int nr)
Java API: Constructor that sets nrOfInstances to be created. |
|
ConsistentHashingRouter(int nrOfInstances,
scala.collection.immutable.Iterable<java.lang.String> routees,
scala.Option<Resizer> resizer,
java.lang.String routerDispatcher,
SupervisorStrategy supervisorStrategy,
int virtualNodesFactor,
scala.PartialFunction<java.lang.Object,java.lang.Object> hashMapping)
|
|
ConsistentHashingRouter(java.lang.Iterable<java.lang.String> routeePaths)
Java API: Constructor that sets the routees to be used. |
|
ConsistentHashingRouter(Resizer resizer)
Java API: Constructor that sets the resizer to be used. |
Method Summary | |
---|---|
static ConsistentHashingRouter |
apply(scala.collection.immutable.Iterable<ActorRef> routees)
Creates a new ConsistentHashingRouter, routing to the specified routees |
static ConsistentHashingRouter |
create(java.lang.Iterable<ActorRef> routees)
|
scala.PartialFunction<java.lang.Object,java.lang.Object> |
hashMapping()
|
int |
nrOfInstances()
|
RouterConfig |
overrideUnsetConfig(RouterConfig other)
|
scala.Option<Resizer> |
resizer()
Routers with dynamically resizable number of routees return the Resizer
to use. |
scala.collection.immutable.Iterable<java.lang.String> |
routees()
|
java.lang.String |
routerDispatcher()
Dispatcher ID to use for running the “head” actor, i.e. |
SupervisorStrategy |
supervisorStrategy()
SupervisorStrategy for the created Router actor. |
int |
virtualNodesFactor()
|
ConsistentHashingRouter |
withDispatcher(java.lang.String dispatcherId)
Java API for setting routerDispatcher |
RouterConfig |
withFallback(RouterConfig other)
Uses the resizer and/or the supervisor strategy of the given Routerconfig if this RouterConfig doesn't have one, i.e. |
ConsistentHashingRouter |
withHashMapper(ConsistentHashingRouter.ConsistentHashMapper mapping)
Java API for setting the mapping from message to the data to use for the consistent hash key. |
ConsistentHashingRouter |
withResizer(Resizer resizer)
Java API for setting the resizer to be used. |
ConsistentHashingRouter |
withSupervisorStrategy(SupervisorStrategy strategy)
Java API for setting the supervisor strategy to be used for the “head” Router actor. |
ConsistentHashingRouter |
withVirtualNodesFactor(int vnodes)
Java API for setting the number of virtual nodes per node, used in ConsistentHash |
Methods inherited from class java.lang.Object |
---|
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait |
Methods inherited from interface akka.routing.ConsistentHashingLike |
---|
createRoute |
Methods inherited from interface akka.routing.RouterConfig |
---|
createActor, createRoute, createRouteeProvider, stopRouterWhenAllRouteesRemoved, toAll, verifyConfig |
Methods inherited from interface scala.Product |
---|
productArity, productElement, productIterator, productPrefix |
Methods inherited from interface scala.Equals |
---|
canEqual, equals |
Constructor Detail |
---|
public ConsistentHashingRouter(int nrOfInstances, scala.collection.immutable.Iterable<java.lang.String> routees, scala.Option<Resizer> resizer, java.lang.String routerDispatcher, SupervisorStrategy supervisorStrategy, int virtualNodesFactor, scala.PartialFunction<java.lang.Object,java.lang.Object> hashMapping)
public ConsistentHashingRouter(int nr)
public ConsistentHashingRouter(java.lang.Iterable<java.lang.String> routeePaths)
routeePaths
- string representation of the actor paths of the routees that will be looked up
using actorFor
in ActorRefProvider
public ConsistentHashingRouter(Resizer resizer)
Method Detail |
---|
public static ConsistentHashingRouter apply(scala.collection.immutable.Iterable<ActorRef> routees)
public static ConsistentHashingRouter create(java.lang.Iterable<ActorRef> routees)
public int nrOfInstances()
nrOfInstances
in interface ConsistentHashingLike
public scala.collection.immutable.Iterable<java.lang.String> routees()
routees
in interface ConsistentHashingLike
public scala.Option<Resizer> resizer()
RouterConfig
Resizer
to use. The resizer is invoked once when the router is created, before any messages can
be sent to it. Resize is also triggered when messages are sent to the routees, and the
resizer is invoked asynchronously, i.e. not necessarily before the message has been sent.
resizer
in interface RouterConfig
public java.lang.String routerDispatcher()
RouterConfig
Router
.
routerDispatcher
in interface RouterConfig
public SupervisorStrategy supervisorStrategy()
RouterConfig
supervisorStrategy
in interface RouterConfig
public int virtualNodesFactor()
virtualNodesFactor
in interface ConsistentHashingLike
public scala.PartialFunction<java.lang.Object,java.lang.Object> hashMapping()
hashMapping
in interface ConsistentHashingLike
public ConsistentHashingRouter withDispatcher(java.lang.String dispatcherId)
public ConsistentHashingRouter withSupervisorStrategy(SupervisorStrategy strategy)
public ConsistentHashingRouter withResizer(Resizer resizer)
public ConsistentHashingRouter withVirtualNodesFactor(int vnodes)
ConsistentHash
public ConsistentHashingRouter withHashMapper(ConsistentHashingRouter.ConsistentHashMapper mapping)
public RouterConfig withFallback(RouterConfig other)
hashMapping
defined in code, since that can't be defined in configuration.
withFallback
in interface RouterConfig
public RouterConfig overrideUnsetConfig(RouterConfig other)
|
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