Package org.apache.hadoop.service

Class ServiceOperations.ServiceListeners

java.lang.Object

org.apache.hadoop.service.ServiceOperations.ServiceListeners

Enclosing class:

ServiceOperations

public static class ServiceOperations.ServiceListeners
extends Object

Class to manage a list of ServiceStateChangeListener instances, including a notification loop that is robust against changes to the list during the notification process.

Constructor Summary

Constructors

Constructor	Description
ServiceListeners()

Method Summary

Modifier and Type	Method	Description
void	add(ServiceStateChangeListener l)	Thread-safe addition of a new listener to the end of a list.
void	notifyListeners(Service service)	Change to a new state and notify all listeners.
boolean	remove(ServiceStateChangeListener l)	Remove any registration of a listener from the listener list.
void	reset()	Reset the listener list

Methods inherited from class java.lang.Object

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

Constructor Details

ServiceListeners

public ServiceListeners()

Method Details

add

public void add(ServiceStateChangeListener l)

Thread-safe addition of a new listener to the end of a list. Attempts to re-register a listener that is already registered will be ignored.

Parameters:

l - listener

remove

public boolean remove(ServiceStateChangeListener l)

Remove any registration of a listener from the listener list.

Parameters:

l - listener

Returns:

true if the listener was found (and then removed)

reset

public void reset()

Reset the listener list

notifyListeners

public void notifyListeners(Service service)

Change to a new state and notify all listeners. This method will block until all notifications have been issued. It caches the list of listeners before the notification begins, so additions or removal of listeners will not be visible.

Parameters:

service - the service that has changed state