alluxio.client.job

Class JobContext

java.lang.Object

alluxio.client.job.JobContext

All Implemented Interfaces:

java.io.Closeable, java.lang.AutoCloseable

@ThreadSafe
public final class JobContext
extends java.lang.Object
implements java.io.Closeable

A shared context that isolates all operations within the same JVM. Usually, one user only needs one instance of JobContext for interacting with job service.

NOTE: The context maintains a pool of job master clients that is already thread-safe. Synchronizing JobContext methods could lead to deadlock: thread A attempts to acquire a client when there are no clients left in the pool and blocks holding a lock on the JobContext, when thread B attempts to release a client it owns it is unable to do so, because thread A holds the lock on JobContext.

Method Summary

Modifier and Type	Method and Description
JobMasterClient	acquireMasterClient() Acquires a job master client from the job master client pool.
CloseableResource<JobMasterClient>	acquireMasterClientResource() Acquires a job master client from the job master client pool.
void	close() Closes all the resources associated with the context.
static JobContext	create(AlluxioConfiguration alluxioConf, UserState userState) Creates a job context.
java.net.InetSocketAddress	getJobMasterAddress()
void	releaseMasterClient(JobMasterClient masterClient) Releases a job master client into the job master client pool.

Methods inherited from class java.lang.Object

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

Method Detail

create

public static JobContext create(AlluxioConfiguration alluxioConf,
                                UserState userState)

Creates a job context.

Parameters:

alluxioConf - Alluxio configuration

userState - user state

Returns:

the context

close

public void close()
           throws java.io.IOException

Closes all the resources associated with the context. Make sure all the resources are released back to this context before calling this close. After closing the context, all the resources that acquired from this context might fail.

Specified by:

close in interface java.io.Closeable

Specified by:

close in interface java.lang.AutoCloseable

Throws:

java.io.IOException

getJobMasterAddress

public java.net.InetSocketAddress getJobMasterAddress()
                                               throws UnavailableException

Returns:

the job master address

Throws:

UnavailableException - if the master address cannot be determined

acquireMasterClient

public JobMasterClient acquireMasterClient()

Acquires a job master client from the job master client pool.

Returns:

the acquired job master client

releaseMasterClient

public void releaseMasterClient(JobMasterClient masterClient)

Releases a job master client into the job master client pool.

Parameters:

masterClient - a job master client to release

acquireMasterClientResource

public CloseableResource<JobMasterClient> acquireMasterClientResource()

Acquires a job master client from the job master client pool. The resource is Closeable.

Returns:

the acquired job master client resource