org.apache.hadoop.lib.server

Interface Service

All Known Implementing Classes:

BaseService, FileSystemAccessService, GroupsService, InstrumentationService, SchedulerService

@InterfaceAudience.Private
public interface Service

Service interface for components to be managed by the Server class.

Method Summary

Modifier and Type	Method and Description
void	destroy() Destroy the services.
Class	getInterface() Returns the interface implemented by this service.
Class[]	getServiceDependencies() Returns the service dependencies of this service.
void	init(Server server) Initializes the service.
void	postInit() Post initializes the service.
void	serverStatusChange(Server.Status oldStatus, Server.Status newStatus) Notification callback when the server changes its status.

Method Detail

init

void init(Server server)
   throws ServiceException

Initializes the service. This method is called once, when the Server owning the service is being initialized.

Parameters:

server - the server initializing the service, give access to the server context.

Throws:

ServiceException - thrown if the service could not be initialized.

postInit

void postInit()
       throws ServiceException

Post initializes the service. This method is called by the Server after all services of the server have been initialized.

Throws:

ServiceException - thrown if the service could not be post-initialized.

destroy

void destroy()

Destroy the services. This method is called once, when the Server owning the service is being destroyed.

getServiceDependencies

Class[] getServiceDependencies()

Returns the service dependencies of this service. The service will be instantiated only if all the service dependencies are already initialized.

Returns:

the service dependencies.

getInterface

Class getInterface()

Returns the interface implemented by this service. This interface is used the Server when the Server.get(Class) method is used to retrieve a service.

Returns:

the interface that identifies the service.

serverStatusChange

void serverStatusChange(Server.Status oldStatus,
                        Server.Status newStatus)
                 throws ServiceException

Notification callback when the server changes its status.

Parameters:

oldStatus - old server status.

newStatus - new server status.

Throws:

ServiceException - thrown if the service could not process the status change.