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

java.lang.Object
  extended by org.apache.hadoop.service.AbstractService
      extended by 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)


Copyright © 2013 Apache Software Foundation. All Rights Reserved.