org.apache.twill.api

Interface TwillContext

All Superinterfaces:

DiscoveryServiceClient, ServiceAnnouncer

public interface TwillContext
extends ServiceAnnouncer, DiscoveryServiceClient

Represents the runtime context of a TwillRunnable.

Method Summary

Modifier and Type	Method and Description
Lock	createLock(String name) Creates a Lock for performing locking mechanism within the same TwillApplication.
ServiceDiscovered	discover(String name) Discover service with the given name that is announced within the same TwillApplication.
Cancellable	electLeader(String name, ElectionHandler participantHandler) Register to participate in a leader election by instances within the same TwillApplication.
String[]	getApplicationArguments() Returns the runtime arguments that are passed to the TwillApplication.
RunId	getApplicationRunId() Returns the RunId of this running application.
String[]	getArguments() Returns the runtime arguments that are passed to the TwillRunnable.
InetAddress	getHost() Returns the hostname that the runnable is running on.
int	getInstanceCount() Returns the number of running instances assigned for this TwillRunnable.
int	getInstanceId() Returns an integer id from 0 to (instanceCount - 1).
int	getMaxMemoryMB() Returns the amount of memory in MB the runnable is allowed to use.
RunId	getRunId() Returns the RunId of this running instance of TwillRunnable.
TwillRunnableSpecification	getSpecification() Returns the TwillRunnableSpecification that was created by TwillRunnable.configure().
int	getVirtualCores() Returns the number of virtual cores the runnable is allowed to use.

Methods inherited from interface org.apache.twill.api.ServiceAnnouncer

announce, announce

Method Detail

getRunId

RunId getRunId()

Returns the RunId of this running instance of TwillRunnable.

getApplicationRunId

RunId getApplicationRunId()

Returns the RunId of this running application.

getInstanceCount

int getInstanceCount()

Returns the number of running instances assigned for this TwillRunnable.

getHost

InetAddress getHost()

Returns the hostname that the runnable is running on.

getArguments

String[] getArguments()

Returns the runtime arguments that are passed to the TwillRunnable.

getApplicationArguments

String[] getApplicationArguments()

Returns the runtime arguments that are passed to the TwillApplication.

getSpecification

TwillRunnableSpecification getSpecification()

Returns the TwillRunnableSpecification that was created by TwillRunnable.configure().

getInstanceId

int getInstanceId()

Returns an integer id from 0 to (instanceCount - 1).

getVirtualCores

int getVirtualCores()

Returns the number of virtual cores the runnable is allowed to use.

getMaxMemoryMB

int getMaxMemoryMB()

Returns the amount of memory in MB the runnable is allowed to use.

discover

ServiceDiscovered discover(String name)

Discover service with the given name that is announced within the same TwillApplication.

Specified by:

discover in interface DiscoveryServiceClient

Parameters:

name - Name of the service

Returns:

A ServiceDiscovered object representing the result.

electLeader

Cancellable electLeader(String name,
                        ElectionHandler participantHandler)

Register to participate in a leader election by instances within the same TwillApplication.

Parameters:

name - Unique name for the election

Returns:

A Cancellable object representing this candidate's participation.

createLock

Lock createLock(String name)

Creates a Lock for performing locking mechanism within the same TwillApplication. The lock created is a reentrant such that if the lock is owned by the current thread, it will return immediately.

Parameters:

name - Unique name for the lock

Returns:

A Lock object