org.apache.hadoop.yarn.util
Class AbstractLivelinessMonitor<O>

java.lang.Object
  org.apache.hadoop.service.AbstractService
      org.apache.hadoop.yarn.util.AbstractLivelinessMonitor<O>

All Implemented Interfaces:

Closeable, Service

@InterfaceAudience.Public
@InterfaceStability.Evolving
public abstract class AbstractLivelinessMonitor<O>
extends AbstractService

A simple liveliness monitor with which clients can register, trust the component to monitor liveliness, get a call-back on expiry and then finally unregister.

Field Summary

static int

DEFAULT_EXPIRE

Constructor Summary

AbstractLivelinessMonitor(String name, Clock clock)

Method Summary

protected abstract void	expire(O ob)
void	receivedPing(O ob)
void	register(O ob)
protected void	serviceStart() Actions called during the INITED to STARTED transition.
protected void	serviceStop() Actions called during the transition to the STOPPED state.
protected void	setExpireInterval(int expireInterval)
protected void	setMonitorInterval(int monitorInterval)
void	unregister(O ob)

Methods inherited from class org.apache.hadoop.service.AbstractService

close, getBlockers, getConfig, getFailureCause, getFailureState, getLifecycleHistory, getName, getServiceState, getStartTime, init, isInState, noteFailure, putBlocker, registerGlobalListener, registerServiceListener, removeBlocker, serviceInit, setConfig, start, stop, toString, unregisterGlobalListener, unregisterServiceListener, waitForServiceToStop

Methods inherited from class java.lang.Object

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

Field Detail

DEFAULT_EXPIRE

public static final int DEFAULT_EXPIRE

See Also:

Constant Field Values

Constructor Detail

AbstractLivelinessMonitor

public AbstractLivelinessMonitor(String name,
                                 Clock clock)

Method Detail

serviceStart

protected void serviceStart()
                     throws Exception

Description copied from class: AbstractService

Actions called during the INITED to STARTED transition. This method will only ever be called once during the lifecycle of a specific service instance. Implementations do not need to be synchronized as the logic in AbstractService.start() prevents re-entrancy.

Overrides:

serviceStart in class AbstractService

Throws:

Exception - if needed -these will be caught, wrapped, and trigger a service stop

serviceStop

protected void serviceStop()
                    throws Exception

Description copied from class: AbstractService

Actions called during the transition to the STOPPED state. This method will only ever be called once during the lifecycle of a specific service instance. Implementations do not need to be synchronized as the logic in AbstractService.stop() prevents re-entrancy. Implementations MUST write this to be robust against failures, including checks for null references -and for the first failure to not stop other attempts to shut down parts of the service.

Overrides:

serviceStop in class AbstractService

Throws:

Exception - if needed -these will be caught and logged.

expire

protected abstract void expire(O ob)

setExpireInterval

protected void setExpireInterval(int expireInterval)

setMonitorInterval

protected void setMonitorInterval(int monitorInterval)

receivedPing

public void receivedPing(O ob)

register

public void register(O ob)

unregister

public void unregister(O ob)