java.lang.Object
- akka.actor.SupervisorStrategy

Direct Known Subclasses:

AllForOneStrategy, OneForOneStrategy
```
public abstract class SupervisorStrategy
extends java.lang.Object
```
An Akka SupervisorStrategy is the policy to apply for crashing children.
IMPORTANT:
You should not normally need to create new subclasses, instead use the existing OneForOneStrategy or AllForOneStrategy, but if you do, please read the docs of the methods below carefully, as incorrect implementations may lead to “blocked” actor systems (i.e. permanently suspended actors).

Nested Class Summary

Nested Classes
Modifier and Type	Class	Description
`static interface`	`SupervisorStrategy.Directive`
`static class`	`SupervisorStrategy.Escalate$`	Escalates the failure to the supervisor of the supervisor, by rethrowing the cause of the failure, i.e.
`static class`	`SupervisorStrategy.Restart$`	Discards the old Actor instance and replaces it with a new, then resumes message processing.
`static class`	`SupervisorStrategy.Resume$`	Resumes message processing for the failed Actor
`static class`	`SupervisorStrategy.Stop$`	Stops the Actor

Constructor Summary

Constructors
Constructor Description

SupervisorStrategy()

Method Summary

All Methods Static Methods Instance Methods Abstract Methods Concrete Methods
Modifier and Type	Method	Description
`abstract scala.PartialFunction<java.lang.Throwable,SupervisorStrategy.Directive>`	`decider()`	Returns the Decider that is associated with this SupervisorStrategy.
`static scala.PartialFunction<java.lang.Throwable,SupervisorStrategy.Directive>`	`defaultDecider()`	When supervisorStrategy is not specified for an actor this `Decider` is used by default in the supervisor strategy.
`static SupervisorStrategy`	`defaultStrategy()`	When supervisorStrategy is not specified for an actor this is used by default.
`static SupervisorStrategy.Escalate$`	`escalate()`	Java API: Returning this directive escalates the failure to the supervisor of the supervisor, by rethrowing the cause of the failure, i.e.
`abstract void`	`handleChildTerminated(ActorContext context, ActorRef child, scala.collection.Iterable<ActorRef> children)`	This method is called after the child has been removed from the set of children.
`boolean`	`handleFailure(ActorContext context, ActorRef child, java.lang.Throwable cause, ChildRestartStats stats, scala.collection.Iterable<ChildRestartStats> children)`	This is the main entry point: in case of a child’s failure, this method must try to handle the failure by resuming, restarting or stopping the child (and returning `true`), or it returns `false` to escalate the failure, which will lead to this actor re-throwing the exception which caused the failure.
`void`	`logFailure(ActorContext context, ActorRef child, java.lang.Throwable cause, SupervisorStrategy.Directive decision)`	Default logging of actor failures when `loggingEnabled()` is `true`.
`protected boolean`	`loggingEnabled()`	Logging of actor failures is done when this is `true`.
`static scala.PartialFunction<java.lang.Throwable,SupervisorStrategy.Directive>`	`makeDecider(Function<java.lang.Throwable,SupervisorStrategy.Directive> func)`	Converts a Java Decider into a Scala Decider
`static scala.PartialFunction<java.lang.Throwable,SupervisorStrategy.Directive>`	`makeDecider(java.lang.Iterable<java.lang.Class<? extends java.lang.Throwable>> trapExit)`	Decider builder which just checks whether one of the given Throwables matches the cause and restarts, otherwise escalates.
`static scala.PartialFunction<java.lang.Throwable,SupervisorStrategy.Directive>`	`makeDecider(scala.collection.immutable.Seq<java.lang.Class<? extends java.lang.Throwable>> trapExit)`	Decider builder which just checks whether one of the given Throwables matches the cause and restarts, otherwise escalates.
`static scala.PartialFunction<java.lang.Throwable,SupervisorStrategy.Directive>`	`makeDecider(scala.collection.Iterable<scala.Tuple2<java.lang.Class<? extends java.lang.Throwable>,SupervisorStrategy.Directive>> flat)`	Decider builder for Iterables of cause-directive pairs, e.g.
`abstract void`	`processFailure(ActorContext context, boolean restart, ActorRef child, java.lang.Throwable cause, ChildRestartStats stats, scala.collection.Iterable<ChildRestartStats> children)`	This method is called to act on the failure of a child: restart if the flag is true, stop otherwise.
`static SupervisorStrategy.Restart$`	`restart()`	Java API: Returning this directive discards the old Actor instance and replaces it with a new, then resumes message processing.
`static SupervisorStrategy.Directive`	`restart(Logging.LogLevel logLevel)`	Returning this directive discards the old Actor instance and replaces it with a new, then resumes message processing.
`void`	`restartChild(ActorRef child, java.lang.Throwable cause, boolean suspendFirst)`	Restart the given child, possibly suspending it first.
`static SupervisorStrategy.Resume$`	`resume()`	Java API: Returning this directive resumes message processing for the failed Actor
`static SupervisorStrategy.Directive`	`resume(Logging.LogLevel logLevel)`	Returning this directive resumes message processing for the failed Actor.
`void`	`resumeChild(ActorRef child, java.lang.Throwable cause)`	Resume the previously failed child: do never apply this to a child which is not the currently failing child.
`static scala.PartialFunction<java.lang.Throwable,SupervisorStrategy.Directive>`	`seqCauseDirective2Decider(scala.collection.Iterable<scala.Tuple2<java.lang.Class<? extends java.lang.Throwable>,SupervisorStrategy.Directive>> trapExit)`
`static scala.PartialFunction<java.lang.Throwable,SupervisorStrategy.Directive>`	`seqThrowable2Decider(scala.collection.immutable.Seq<java.lang.Class<? extends java.lang.Throwable>> trapExit)`	Implicit conversion from `Seq` of Throwables to a `Decider`.
`static SupervisorStrategy.Stop$`	`stop()`	Java API: Returning this directive stops the Actor
`static SupervisorStrategy.Directive`	`stop(Logging.LogLevel logLevel)`	Returning this directive stops the Actor
`static SupervisorStrategy`	`stoppingStrategy()`	This strategy resembles Erlang in that failing children are always terminated (one-for-one).

Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

- Constructor Detail
  - SupervisorStrategy
```
public SupervisorStrategy()
```
- Method Detail
  - resume
```
public static SupervisorStrategy.Resume$ resume()
```
    Java API: Returning this directive resumes message processing for the failed Actor
  - resume
```
public static SupervisorStrategy.Directive resume(Logging.LogLevel logLevel)
```
    Returning this directive resumes message processing for the failed Actor.
    
    Parameters:
    
    logLevel - Log level which will be used to log the failure
  - restart
```
public static SupervisorStrategy.Restart$ restart()
```
    Java API: Returning this directive discards the old Actor instance and replaces it with a new, then resumes message processing.
  - restart
```
public static SupervisorStrategy.Directive restart(Logging.LogLevel logLevel)
```
    Returning this directive discards the old Actor instance and replaces it with a new, then resumes message processing.
    
    Parameters:
    
    logLevel - Log level which will be used to log the failure
  - stop
```
public static SupervisorStrategy.Stop$ stop()
```
    Java API: Returning this directive stops the Actor
  - stop
```
public static SupervisorStrategy.Directive stop(Logging.LogLevel logLevel)
```
    Returning this directive stops the Actor
    
    Parameters:
    
    logLevel - Log level which will be used to log the failure
  - escalate
```
public static SupervisorStrategy.Escalate$ escalate()
```
    Java API: Returning this directive escalates the failure to the supervisor of the supervisor, by rethrowing the cause of the failure, i.e. the supervisor fails with the same exception as the child.
  - defaultDecider
```
public static final scala.PartialFunction<java.lang.Throwable,SupervisorStrategy.Directive> defaultDecider()
```
    When supervisorStrategy is not specified for an actor this Decider is used by default in the supervisor strategy. The child will be stopped when ActorInitializationException, ActorKilledException, or DeathPactException is thrown. It will be restarted for other Exception types. The error is escalated if it's a Throwable, i.e. Error.
  - defaultStrategy
```
public static final SupervisorStrategy defaultStrategy()
```
    When supervisorStrategy is not specified for an actor this is used by default. OneForOneStrategy with decider defined in defaultDecider().
  - stoppingStrategy
```
public static final SupervisorStrategy stoppingStrategy()
```
    This strategy resembles Erlang in that failing children are always terminated (one-for-one).
  - seqThrowable2Decider
```
public static scala.PartialFunction<java.lang.Throwable,SupervisorStrategy.Directive> seqThrowable2Decider(scala.collection.immutable.Seq<java.lang.Class<? extends java.lang.Throwable>> trapExit)
```
    Implicit conversion from Seq of Throwables to a Decider. This maps the given Throwables to restarts, otherwise escalates.
  - makeDecider
```
public static scala.PartialFunction<java.lang.Throwable,SupervisorStrategy.Directive> makeDecider(scala.collection.immutable.Seq<java.lang.Class<? extends java.lang.Throwable>> trapExit)
```
    Decider builder which just checks whether one of the given Throwables matches the cause and restarts, otherwise escalates.
  - makeDecider
```
public static scala.PartialFunction<java.lang.Throwable,SupervisorStrategy.Directive> makeDecider(java.lang.Iterable<java.lang.Class<? extends java.lang.Throwable>> trapExit)
```
    Decider builder which just checks whether one of the given Throwables matches the cause and restarts, otherwise escalates.
  - makeDecider
```
public static scala.PartialFunction<java.lang.Throwable,SupervisorStrategy.Directive> makeDecider(scala.collection.Iterable<scala.Tuple2<java.lang.Class<? extends java.lang.Throwable>,SupervisorStrategy.Directive>> flat)
```
    Decider builder for Iterables of cause-directive pairs, e.g. a map obtained from configuration; will sort the pairs so that the most specific type is checked before all its subtypes, allowing carving out subtrees of the Throwable hierarchy.
  - makeDecider
```
public static scala.PartialFunction<java.lang.Throwable,SupervisorStrategy.Directive> makeDecider(Function<java.lang.Throwable,SupervisorStrategy.Directive> func)
```
    Converts a Java Decider into a Scala Decider
  - seqCauseDirective2Decider
```
public static scala.PartialFunction<java.lang.Throwable,SupervisorStrategy.Directive> seqCauseDirective2Decider(scala.collection.Iterable<scala.Tuple2<java.lang.Class<? extends java.lang.Throwable>,SupervisorStrategy.Directive>> trapExit)
```
  - decider
```
public abstract scala.PartialFunction<java.lang.Throwable,SupervisorStrategy.Directive> decider()
```
    Returns the Decider that is associated with this SupervisorStrategy. The Decider is invoked by the default implementation of handleFailure to obtain the Directive to be applied.
  - handleChildTerminated
```
public abstract void handleChildTerminated(ActorContext context,
                                           ActorRef child,
                                           scala.collection.Iterable<ActorRef> children)
```
    This method is called after the child has been removed from the set of children. It does not need to do anything special. Exceptions thrown from this method do NOT make the actor fail if this happens during termination.
  - processFailure
```
public abstract void processFailure(ActorContext context,
                                    boolean restart,
                                    ActorRef child,
                                    java.lang.Throwable cause,
                                    ChildRestartStats stats,
                                    scala.collection.Iterable<ChildRestartStats> children)
```
    This method is called to act on the failure of a child: restart if the flag is true, stop otherwise.
  - handleFailure
```
public boolean handleFailure(ActorContext context,
                             ActorRef child,
                             java.lang.Throwable cause,
                             ChildRestartStats stats,
                             scala.collection.Iterable<ChildRestartStats> children)
```
    This is the main entry point: in case of a child’s failure, this method must try to handle the failure by resuming, restarting or stopping the child (and returning true), or it returns false to escalate the failure, which will lead to this actor re-throwing the exception which caused the failure. The exception will not be wrapped.
    This method calls logFailure(akka.actor.ActorContext, akka.actor.ActorRef, java.lang.Throwable, akka.actor.SupervisorStrategy.Directive), which will log the failure unless it is escalated. You can customize the logging by setting loggingEnabled() to false and do the logging inside the decider or override the logFailure method.
    
    Parameters:
    
    children - is a lazy collection (a view)
  - loggingEnabled
```
protected boolean loggingEnabled()
```
    Logging of actor failures is done when this is true.
  - logFailure
```
public void logFailure(ActorContext context,
                       ActorRef child,
                       java.lang.Throwable cause,
                       SupervisorStrategy.Directive decision)
```
    Default logging of actor failures when loggingEnabled() is true. Escalate failures are not logged here, since they are supposed to be handled at a level higher up in the hierarchy. Resume failures are logged at Warning level. Stop and Restart failures are logged at Error level.
  - resumeChild
```
public final void resumeChild(ActorRef child,
                              java.lang.Throwable cause)
```
    Resume the previously failed child: do never apply this to a child which is not the currently failing child. Suspend/resume needs to be done in matching pairs, otherwise actors will wake up too soon or never at all.
  - restartChild
```
public final void restartChild(ActorRef child,
                               java.lang.Throwable cause,
                               boolean suspendFirst)
```
    Restart the given child, possibly suspending it first.
    IMPORTANT:
    If the child is the currently failing one, it will already have been suspended, hence suspendFirst must be false. If the child is not the currently failing one, then it did not request this treatment and is therefore not prepared to be resumed without prior suspend.

Class SupervisorStrategy

Nested Class Summary

Constructor Summary

Method Summary

Methods inherited from class java.lang.Object

Constructor Detail

SupervisorStrategy

Method Detail

resume

resume

restart

restart

stop

stop

escalate

defaultDecider

defaultStrategy

stoppingStrategy

seqThrowable2Decider

makeDecider

makeDecider

makeDecider

makeDecider

seqCauseDirective2Decider

decider

handleChildTerminated

processFailure

handleFailure

loggingEnabled

logFailure

resumeChild

restartChild