org.graylog2.system.shutdown

Class GracefulShutdownService

java.lang.Object

com.google.common.util.concurrent.AbstractIdleService

org.graylog2.system.shutdown.GracefulShutdownService

All Implemented Interfaces:

com.google.common.util.concurrent.Service

@Singleton
public class GracefulShutdownService
extends com.google.common.util.concurrent.AbstractIdleService

A service that participates in the Graylog server graceful shutdown.

Services can implement GracefulShutdownHook and register themselves with this service to make sure they get shut down properly on server shutdown. During shutdown the registered hooks will be called in no particular order.

Make sure to use unregister(GracefulShutdownHook) if a registered service is shutting down before the server shutdown to avoid leaking service instances in the GracefulShutdownService. See GracefulShutdownHook for an example.

Nested Class Summary

Nested classes/interfaces inherited from interface com.google.common.util.concurrent.Service

com.google.common.util.concurrent.Service.Listener, com.google.common.util.concurrent.Service.State

Constructor Summary

Constructors

Constructor and Description
GracefulShutdownService()

Method Summary

Modifier and Type	Method and Description
void	register(GracefulShutdownHook shutdownHook) Register a shutdown hook with the service.
protected void	shutDown()
protected void	startUp()
void	unregister(GracefulShutdownHook shutdownHook) Remove a previously registered shutdown hook from the service.

Methods inherited from class com.google.common.util.concurrent.AbstractIdleService

addListener, awaitRunning, awaitRunning, awaitTerminated, awaitTerminated, executor, failureCause, isRunning, serviceName, startAsync, state, stopAsync, toString

Methods inherited from class java.lang.Object

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

Methods inherited from interface com.google.common.util.concurrent.Service

awaitRunning, awaitTerminated

Constructor Detail

GracefulShutdownService

public GracefulShutdownService()

Method Detail

startUp

protected void startUp()

Specified by:

startUp in class com.google.common.util.concurrent.AbstractIdleService

shutDown

protected void shutDown()

Specified by:

shutDown in class com.google.common.util.concurrent.AbstractIdleService

register

public void register(GracefulShutdownHook shutdownHook)

Register a shutdown hook with the service.

Parameters:

shutdownHook - a class that implements GracefulShutdownHook

Throws:

IllegalStateException - if the server shutdown is already in progress and the hook cannot be registered

NullPointerException - if the shutdown hook argument is null

unregister

public void unregister(GracefulShutdownHook shutdownHook)

Remove a previously registered shutdown hook from the service.

This needs to be called if a registered service will be stopped before the server shuts down.

Parameters:

shutdownHook - a class that implements GracefulShutdownHook

Throws:

IllegalStateException - if the server shutdown is already in progress and the hook cannot be unregistered

NullPointerException - if the shutdown hook argument is null